Frequently Asked Questions

Authors Note:

Because this page got so big, I decided to split it in two.  This FAQ's page deals with questions and answers about the birds themselves, therefore, if you have a question about the martins directly, then you'll find it here.

However, if you have a question about martin housing, then you'll find it here.  I broke that material into a separate category to make it easier to find answers to specific housing questions.

As for generic questions, you'll also find them here.

Also, the answers on this page are using the latest information gleaned, not only from my own experience, but from research that has been done on purple martins in recent years.  The answer to your question may differ from other answers that you may have heard, but I strive to stay with the latest technology in this hobby and therefore, my answers might be a little different.  Where possible, I will state what the 'old' answer may have been and why the 'new' answer is given.

I would like to start a Purple Martin colony.  Is there anything special I should know?

Yes, I'm afraid there is.  Keeping purple martins can be a very gratifying and enjoyable hobby, however it's a lot more complicated than just putting a house on top of a pole and letting them come.  There are requirements that martins have to settle in a new site and if the rules for these requirements aren't followed, martins may never come and the house is then taken over by either English House Sparrows or European Starlings, the martins worst nesting competitors.  In today's instant society, many people just buy one of those 'cute' little store bought houses, stick it up on a pole and then wait for the martins to come and that's about the worst thing one could do.

The first thing you have to do is educate yourself.  Read, read and read some more.  Find out everything you possibly can about them BEFORE you spend money and put up any housing.  Read and understand the Requirements For Attracting them and why people lose them.  Once you begin to understand them, you'll have a much better understanding of how to set up housing for them.

How big should the entrance hole be for martins?

Depending on where you get your information from, many outdated specification sheets available on this subject say the entrance hole for purple martins can be anywhere from 1 3/4" to 2 1/4" in diameter, with 2" being common. However, that is old school.  In recent years, much has been learned about the purple martin and their interactions with the European Starling and, because of that, new methods are being devised to keep starlings out of martin housing.  Although some commercial houses are still sold with the old round holes in them, the more responsible housing manufacturers are making the change to some form of SREH (Starling Resistant Entrance Hole) to protect martins.  There are a number of different styles available that have been tested and work very well.  If you want to build your own, then do a little investigation on them and see which ones you can most easily make or which ones you like best.  Then the decision for the entrance hole size and style is yours.  I use both the original Crescent and a spin-off of it called the Clinger in my own colony and both work very well.

There are still many areas of the country where round 2" holes are still being used, but because so many other areas of the country are becoming infested with European Starlings, it is now highly recommended that round hole designs be changed to some form of SREH.  A lot of testing has gone into many different shapes to create an entrance hole that will keep starlings out of martin housing, and because of the starling invasion, one of them should be used.  The two designs mentioned have proven to be very effective as a deterrent for starlings.  SREH's are quickly becoming the newest standard for entrance holes for purple martins.  My entire site has SREH's and is now starling free.  In fact, many other sites in my immediate area have also changed over and they too, are no longer bothered by starlings entering the martin housing.

Also, it has been discovered that the material that the SREH's are cut into should be no thicker than 1/8".  Anything thicker, such as a 3/4" thick front door to a martin house, just won't let the martins get in.  The thick material doesn't allow the martins to pull their legs in to get a grip thus, they can't negotiate them.

But I'm just starting out. Wouldn't it be better to start with round holes and then switch over to SREH's after the birds are established?

The answer to this has two considerations:

If you live where there are NO starlings and they do not bother your housing, then yes, it's OK to start with round 2" diameter holes.  This means that NO starlings visit your site, period.  as mentioned above, there are still some places in the country that are still starling free at their martin sites, but those places are quickly becoming few and far between.

However, if ANY starlings come to your site at all, then the answer is NO. Starlings will be in your housing before you can get back in the house.

It was once thought that a new site should start with the round holes and then change to the crescents after the birds settle in, but that theory is now 'old school' when it comes to European Starlings in a martin colony. Martins will readily accept the new SREH shaped holes and, where starlings are present, the round holes are being eliminated.  Martins do not look at the geometry of a hole, they only see a black opening and once they look in, know that there's an empty cavity behind it that is suitable for nesting.  However, if the compartment behind the crescent is not to the martins liking, they may not even try to enter.  Just like any other cavity nesting bird, they like nice, large and 'horizontally deep' cavities.  If the cavity is at least 9" or 10" deep, they'll make every effort to enter when they are ready.  If not, then they may look elsewhere.

A few other notes:

If you start out with Crescent SREH's, it will eliminate any problems you have with starlings right from the get go.  In fact, you'll actually enjoy watching the starlings as they are bewildered at these holes they can't get into.

Crescents are not starling PROOF, but are starling RESISTANT.  This means that sooner or later, a starling that is small enough is going to break your SREH code and enter a cavity.  In this case, that starling will have to be dealt with by other means such as trapping or shooting.  

I tried the SREH holes, but my martins couldn't make it through them, so I changed back to the round holes.

This feeling that landlords get when they see their martins first struggling to get in SREH holes is known as SREH Anxiety.  When martins that have never seen some sort of SREH first encounter these type holes, they will 'seem' apprehensive and balk at going thru them.  What happens is the martins feel the pressure on their backs and breasts and they need time to overcome this apprehension.  For some, this may take a day or two for them to get used to the pressure, for others, only an hour or even less, but once they accept the feeling of the pressures on their bodies, and with that cavity behind that hole being so inviting, within a very short time, they will all be negotiating them without any problem at all.

ALL of my housing has SREH entrances of some sort (crescent and clinger) and I can assure you your martins will learn to use them just as mine do.  I know it's hard to watch them struggle that first time they try to enter, but believe it or not, the best thing a landlord can do is not watch.  We as humans have emotions that sometimes get in the way, but martins on the other hand live by instincts and they see that hole and the drive to breed and produce young is very strong and before you know it, they'll overcome the apprehension and figure out the holes. There is a learning curve to everything new, so give them a chance to learn to use them and then both you and they will be much better for it.  

And one more point.  So many landlords are changing over to SREH entrances, the martins that come to visit your site might already know all about these holes and zip right in.

One thing I was wondering is, once they get big enough, can the fledging martins get out of crescents?

Absolutely.  Young martins have no problems negotiating SREH's at all.  In fact, since they grew up 'inside' them and then learned to come out of them on their first flight, getting back in is a snap.

However, learning to land is another story.  Young martins have to learn to fly and land regardless of what kind of hole you use and watching that is a treat in itself.  The antics they go through to learn the timing of landing and holding on is sometimes hilarious.  Now, to us it may be humorous, but to them it's a matter of life and death that they quickly learn to fly and land.  Many a predator is lurking, looking for just such an opportunity to snatch one of them away for lunch.

According to all reports, the scouts are already through my area. Is it too late for me to get martins this year?

No, just because the scouts are through your area doesn't mean you've missed your chance to get a colony. In fact, the scouts are only the very FIRST birds to reach your area (or go thru it), so you still have considerable more time left.  All new colonies have to start somewhere and, although it does happen occasionally, it's usually not done with 'Scouts'.

I had some 'scouts' come check out my site and then left.  Did they go back to get the rest of the flock?

NO, scouts do not return south for the rest of the flock, that is a Myth passed down thru the ages by folks that don't fully understand their martins

What normally happens is, the most mature birds return north first.  As martins get older, they learn that the sooner they get to a site, the better chance they have of getting the best nesting cavity since that's how females select a mate.  These first birds to return are usually called scouts. 

Once arriving at their home site, they will often disappear for a couple of days, giving the impression that they went back to get the flock, but instead, they are just still being wild birds and are still staying in trees or on power lines for the night.  Sometimes, they'll spend the night in the housing, but not always.  Remember, the 'only' time they normally stay in housing is during the nesting cycle.

I've read where I should wait 4 weeks after I see the first scouts to put my housing up.  Why is that?

It was originally thought that the only way a 'new' colony would get established was with the returning SY birds.  Supposedly they were the ones that colonized new sites.  Plus, it was thought that if you put your housing up too early, the pest birds would inhabit it long before the martins got back.  However that way of thinking has now changed.  It's now 'suggested' that you put your housing up when the scouts arrive because some of the older birds just might find your site more attractive than their old one and move.  Martins have a very strong site fidelity for their home sites, but if for whatever reason it becomes run down or infested with pest birds, it is now recognized that they will move to another site.  Therefore, don't wait.  Put your housing up when you see or hear news of the scouts.  You can check out the approximate arrival dates for your particular area with the Map on this page.  And make sure you use SREH's and sparrow control.

What in the world is meant by HY, SY and ASY?

These are nothing more than acronyms or, shortened terms, for a quick way of expressing the age of the birds you're dealing with and is usually determined by the plumage.  

HY, (Hatching Year) birds born [hatched] this year. 

SY, (Second Year) birds born last year, are returning from migration for the first time and still have adolescent plumage . 

ASY, (After Second Year) birds born at least two years ago and have now attained their adult plumage.

SREH.  (Starling Resistant Entrance Hole).  This has to do with the new types of entrance holes used to help keep starlings out of housing.

S&S (Starlings & Sparrows).  A short way to describe two of the martins worst enemies.

So, when do martins get their 'all black' look.

All birds molt every year and replace their old feathers with new ones.  Martins molt during the winter months while in their southern hangouts, even the young.  The females will look pretty much the same from year to year with maybe just a little color change as they get older, but it's the males where the change is most noticeable.  Second year males will get their darker back, neck and cap plumage along with a few black feathers on their breasts and thus the term, SY.  Only after molting from their second trip south will they achieve their full cloak of all black plumage, thus the term, ASY.  This transition of plumage change over two or more seasons is known as Delayed Plumage Maturation.

Do the martins nest while in South America?

No!  Purple martins nest exclusively here in North America during our summer.  They then fly to South America during the winter months where they molt and acquire a new set of feathers.  All birds do it at sometime during the year.  With the martins, it's while they are in their southern range.

Martins spent the night in my house. Will they stay?

To be honest, I can’t answer that question, nor can anyone else. We are dealing with wild creatures and I have no clue whether they will stay or not. They might be just passing through or they may actually be looking for a place to set up housekeeping. If the former is the case, then they will be moving on to the site where they nested last year. If the latter is the case, then they've found your site to be interesting enough to investigate. This is why, as potential landlords, we should do all we can to insure that our houses are as good and safe as can be. If the birds think the same thing, then there is a good chance that they will stay.

I have old bird nests in my housing.  Should I remove them?  What kind of soap should I use to clean out the compartments?

If you had martins, or any other bird for that matter, nest in your housing, then all you have to do is remove the nesting materials.  No, you do not need to go into any kind of detail such as washing it all out or using soap or anything like that.  All that precaution is not necessary.

However, there are those folks that like to keep their housing clean and many remove the old nesting materials and then use a garden hose and spray the compartments to wash out any residue.  Many even take all their housing down each year.  It's just a matter of how much work you want to go to.

One more thing:  If you had nest mites during the previous season, then yes, those nests need to be removed and you might want to take some alcohol and wipe down the compartments.  Alcohol kills the mites and the vapors from it dissipate very quickly.  The house is usually ready to use by the time you put it back up.

One other thing that can be done is to give a very light sprinkling of 5% Sevin dust to the compartment.  That will also eliminate any mites.

I've read that martins like eggshells.  Will this help attract them?

No, not really.  Yes, it's true that martins like eggshells, but this is usually only during the nesting periods.  The females use them for grit and a source of calcium which they need to make their own eggshells stronger.  They also use them for grit for the young during brood rearing.  Putting eggshells out before martins arrive may also attract other birds in your yard however; that's not all that bad either.  If they are native birds, then they too will need and use them for the very same reasons.

If you have an established colony and want to offer eggshells, then simply make a small platform feeder (similar to the one shown here) and fill it with crushed eggshells.  They are easy to prepare and your birds will love them.  Wash your eggshells with plain water to remove the inner membrane.  Then, set them out in the sun to dry.  After they dry, crush them to about the size of your small finger nail and put them in the feeder.  That's all there is to it. 

We don't eat that many eggs at our home.  Is there another way to get some.

There sure is.  One way is to have some of your friends keep eggs shells for you following the cleaning procedures described above.  You pick them up every now and then and add them to your stash. 

Or...

You could go down to your local restaurant and have them save you some.  This could be a Waffle House or Corner Cafe, what ever your local restaurant might be.  When you explain what you want the eggshells for, most are happy to help out.  However, if you plan to acquire some this way, remember to make it easy on them.  Bring them a plastic 5 gallon bucket, lined with a large plastic garbage bag that they can just drop the eggshells into without too much trouble.  Remember, it's a business for them and they need to make money so their time is important.  Then, when the breakfast period is over, go pick up your bucket of eggshells, thank them and then take your eggshells home. 

Now, you've got a mess, right!  Well, yes and no.  First, dump the bag into the bucket and then fill it with 'plain' water, covering the eggshells.  Now, slosh the eggshells around with your hand or a sturdy stick for a few minutes.  (If you use your hands, use rubber gloves to protect your hands from the sharp edges of the eggshells).  This will remove most of the membranes from the shells.  Slowly pour out the water along with the membrane.  Now, you will need some form of cloth bag or pillow case that zips closed or you can simply tie the end closed with a string.  Pour the eggshells into the pillow case and zip it shut.  Hang it somewhere and the excess water will simply drain out.  Leave it until the dripping stops.  Now, toss it into the family dryer and let it run on hot for about 30 minutes to an hour or until they are dry.  Viola, you now have a large amount of eggshells for your eggshell feeder and most are already crushed from the rolling around in the dryer.  It's as simple as that.  This usually ends up being a lot of eggshells.  You may need to divide them up into smaller zip lock plastic bags and sticking them on a shelf somewhere until the birds use them.  Or, you could share them with other martin enthusiasts in your area.

What about the oyster shells?  I've heard they like them too.

I've tried them and unfortunately, my birds do not like them as well as they do the eggshells and in fact, I've ended up dumping them out at the end of the season.  However, I have heard from other landlords that they do use them, so try a few of them.  If your martins like them, then use them.  They work just as well as the eggshells if you can get your martins to use them.

What about perches?  If I add them to my gourds will it help me attract martins?

Actually, this is now a recent discovery.  PORCHES, not 'perches' are now considered a must for housing using the new Starling Resistant Entrance Holes.  Testing has now proven that both external and internal porches set between flush and 1/8" under the bottom of the SREH entrance hole enhances the compartment or gourd and also allows for much easier access into them.  Pest birds such as Sparrows and Starlings will also use these porches, but if the SREH works, then the starlings can't get in anyway.  Also, if the sparrows sit long enough on the porches, they make easy targets for pellet guns or guns of other sorts. 

Martins LOVE roosting perches and these are usually placed somewhere convenient to the gourds or housing and they will be used quite extensively by the martins to do their sunning and preening and just general socializing.  These can be long rods in starburst patterns or crossed bars or what ever you decide to make yours look like.  It gives the birds something to land on when they fly into the site.

We have some birds staying in our house, but we're not sure if they are martins.  How can we tell for sure?

The two birds shown here are purple martins.  The female on the left just happens to be an SY, while the male on the right is an ASY.  If the birds in your house don't look like them, then you don't have martins.  (For more detailed descriptions of all ages of martins, check out the Purple Martin Bio Page).  The first thing you have to do is determine what the birds are.  If they are martins, then all is fine.  If not, and they are friendly 'native' birds, then they should be persuaded to move on, mainly because most native nesting birds are not communal in nature and will chase off other birds that try to nest near them.  Usually removing the nesting material a few times will do it.  If not, then close up the house for a day or two until they move.  If they are another cavity nesting species such as Bluebirds or Tree Swallows, find out what type of housing they require and then put some out for them.  The only reason they're in your martin house is because they can't find housing of their own liking and requirements, elsewhere.  Usually supplying a house made for them about 100 feet away from your colony site will make them move right in once they find it

However, if they turn out to be either European Starlings or English House Sparrows,  then I strongly suggest you eliminate them, period.  Trapping, shooting, whatever it takes.  These two species of birds are mortal enemies of martins and will prevent any martins from nesting in your housing if given the chance.

We have martins that come by during the day, but then disappear at night.  Why won't they stay?

There could be a number of reasons for this.  The birds visiting might be from another site and are enjoying your site a little more than their home site and just might be looking yours over, but for whatever bird reason, (usually site tenacity) are returning to their home site for the night.  If they continue to spend days at your site and like it more, then there is a good chance that they will make the switch and stay.

Or, it could be birds from other colonies visiting your site looking for mates.  If it's males, then they'll try and draw the females away to their site.  If it's females, then they'll be looking to stay at your site in the near future if they find a mate and a compartment they like.

Also, if it's early in the year, they may not be ready to settle down just yet.  Remember, these are wild birds and are used to sleeping in trees or on power lines and radio antennas and aren't ready to settle in just yet.  They just need some time.

We had some martins come by and stay a couple of days, but now they're gone.  Where did they go?

To be honest, I don't know, but here are a couple of possible answers.

One, they could very well be just passing through and found your site to rest for a few days.  This often happens with older birds since they are headed back to the site where they successfully nested last year.  Martins sometimes take a day or two during their migration and stay at any available house that's along the way to rest a little.

Two, it could be very early in the season and they just aren't ready to settle in a house yet.

Three, if these are young SY birds, then there could be any number of reasons.  They are the hardest to predict.  Younger birds just don't seem to be in a hurry to nest and even when they do, their hearts sometimes aren't fully in it.  However, once a nest is completed and eggs are laid, then they will start putting more effort to the task at hand and most of the time, they will succeed in fledging young.

My neighbor has a colony of martins and I would like to attract some of my own, too.  Will I have any problems if I try?

Assuming you put up housing with the new and proper standards and you follow all the rules for attracting martins, then I see no reason why not.  Remember, purple martins are communal nesters and are a very social bird species.  This means they like to have a lot of their kind around when nesting.  If your site is as favorable as your neighbor's, then you should have no problem attracting a colony of your own.  In fact, his having martins just might help.  Start by reading all the information you can about them.  Educate yourself on the do's and don'ts of keeping purple martins.  Then, following those rules you just learned, offer good, quality housing with deep compartments and I'm willing to bet that you'll have a couple of pairs your very first year.  Keep any pest species out of the house and read all about doing nest checks and take care of them.  You'd be surprised at how quick they'll come.

We have martins staying at our new house but they aren't nesting.  What's wrong?

Nothing!  One thing that new martin enthusiasts run into is impatience (myself included when I started).  Remember, these birds are just returning to their northern home and it's been a long flight for them.  They're in no hurry to start nest building upon arrival.  Give them some time.  They need to rest a little, get to know the neighborhood and to also get to know each other.  We as humans want them to stay and nest, but we want it to all happen NOW and that just isn't going to happen.  There are things we humans just don't understand about wild creatures and when they, the weather and the time are right, they'll begin nesting.  In the meantime, just relax and enjoy their antics.  Watch them and learn as much as you can about them.  Little by little, you'll begin to understand and also become a little less impatient and before you know it, they and their young will be gone.

We finally have some martins that are staying in our housing, but they disappear during the afternoon and then come back in just before dark.  Where do they go?

They went to eat.  Remember, martins eat flying insects and have to go in search of them.  (No, they do not eat seeds from bird feeders nor do they drink from bird baths).  They will often eat a little early in the morning and then return and hang around the site for the rest of the morning chattering and socializing and then they are off into the air to eat around noon.  Sometimes, they may travel many miles in search of food and of course, that takes them well away from their home site.  Martins love to fly and they may go as far as 5 or 10 miles in search of their prey, but not to worry, they will always find their way back to your site before dark.

Is it good to put nesting materials in the housing before the martins get back?

Yes...especially if you are using any housing that is 'slick'.  Any of the aluminum and plastic housing is pretty slick under a martin's foot and they can't really get a good foot hold and could get a condition called leg splay.  Adding a couple of inches of nesting materials really gives them a good foundation to stand on and it also helps keep them warm on those first cool days.

Plus, since the advent of the SREH and the internal porches, this added material helps the short legged martin to hop up on the internal porch thus making it easier to exit and enter the compartment or gourd.  I usually add enough to be level with the internal porch because the materials will pack down a little after a the martins walk on it.  The female will usually then add whatever more she wants to 'customize' it to her liking.

I've read where it helps to put nesting material out for the birds.  Does this really help?

Absolutely.  I do and the majority of other landlords I know also do it.  There are a number of different materials that can be used.  Two that I highly recommend are Pine Straw  (dried pine needles) and Wheat Straw.  Both are usually available just about anywhere.  Others are available, but make sure that whatever you use doesn't get wet and stay wet.  The parent birds won't stay in a nest that stays wet.  The two I mentioned will quickly drain off any moisture if they get wet.  You may have heard of using cedar shavings for nesting materials, but I don't like them because they get wet and soak up the water and thus, stay wet.  Plus, in the new plastic and metal housing, these are very slippery for the matins to walk on.  The first two I mentioned give very good footing and plus the female can move them around to make her nest the way she wants it.

One side note:

I once tried wood shavings and the martins threw them all out and replaced them with pine straw that they picked from the pines around my own home, thus, that tells me that they do not prefer shavings in their nest but instead, a more stable material under foot.

So, how do I use it?

I use both the pine straw and wheat straw.  Both are very abundant in my area simply for the raking and bagging.  However, both can also be obtained at just about any garden shop in bales.  You may not need that much for the martins, but the remainder makes great mulch for plants.  I start the year out with pine straw by putting a good base of it in all my cavities before the birds return.  What I do is place enough material in the compartments to come up to the bottom of the entrance hole, or in my case, internal porches.  Martins are short legged birds and are not able to jump very well, so I make it easier on them by placing enough material so that they can simply step up on the edge of the porch.  Then, when they return each spring, they have something to rest and sit on for those first few cool nights. 

Then, around the beginning of nest building time, (you can tell this by watching the martins looking for more nesting materials) I place a raised platform near their racks.  I then cut wheat straw into about 3" or 4" long pieces using a set of pruning shears and add a good quantity to the platform.  My martins know what this is and readily grab it up and use it to 'finish off' their nests to their likings.  Martins are quick learners and it doesn't take them long to learn that this is theirs to use and it takes them no time at all to use it all up.  As your colony grows, you'll find yourself refilling the platform quite often, even daily. 

As a side note, during heavy nest building, I've actually had martins land on the platform and take material while I was filling it.  (Pretty brassy if you ask me).

One more point to elaborate on about adding nesting materials to housing:

Early in the year, those first birds to return may still encounter some very cold nights.  In fact, some of those nights may be well below freezing and if the housing contains a fair amount of dry nesting materials, then the birds will make it thru the night just fine.  No, you do not need to add any kind of warming devices, (as advocated by some), those things are not necessary.  Feathers have very good insulating properties and, as can be seen throughout any winter just about anywhere, those birds do just fine out in the cold.

As long as the birds (any birds) are able to obtain enough food to allow them to generate body heat, then the birds do fine in cold weather.  The problem arises when they are not able to find food.  This goes for any bird, not just martins.  But in the case of martins, they are insectivores and get their food from flying insects and if the insects are not flying, then the martins don't get to eat and thus are not able to maintain that body heat.  After 3 days, a martin's stores are depleted and then they will begin to get in trouble from the cold.  Would it help if the birds are kept warm?  No, the birds are still using their body stores and are in the same trouble. 

Here's one thing that can be done for 'extended' inclement weather situations.  Supplemental Feeding

You said not to use shavings, but I've heard that they help with preventing nest mites?

Sorry, but that is incorrect.  Cedar shavings will do nothing to prevent nest mites.  It was originally believed that the natural resins in cedar prevented nest mites, but it has since been proven, time and again, that this doesn't happen.  The adult birds themselves pick up the mites in their travels and then bring them into the nest where they propagate and become a dangerous pest to the young.

Here are my reasons for not using cedar shavings, nor any other kinds of wood shavings.

...Cedar does have natural resins in it to protect the wood however; these resins are caustic and, although not proven, could harm the young.

...Wood of any kind will absorb water and the nest will not drain well and thus, will stay wet.

...Shavings make for very unsure footing and the martins feel very unsure when they try to walk on them, especially if the housing has slippery floors.

...And, back when I was starting, I tried the cedar shavings and the martins thru them all out and replaced them with pine straw.  I've since learned the reasons why and no longer use them.

We did a nest check and found nesting material in some compartments, but no eggs. Is this normal?

Although not always, when you find a nest that doesn't contain any eggs, it is probably the work of a lone male. Many times single males (called floaters) are known to build a partial nest in the hopes of attracting a female. If they end up not pairing with a female, then the result is a 'partially complete' nest, but no eggs. Pay attention to the nest. If you see only one bird hanging out there, then more than likely the empty nest is the work of a floater.

We found a nest in our house but we're not sure if it's a martin nest or not.  How can we tell?

This is a question that's hard to answer.  Depending on where you live, the materials they use to build their nests may be different.  The picture below is of a martin nest with 5 eggs in it from Florida, but your nests may look different because of where you live.  For instance, in my area, they use a lot of pine straw and green leaves.  The Martin Bio Page will show a couple of different nests to compare with.

In general, martin nests are very low profile, often consisting of sticks and twigs and many leaves.  In some of the smaller compartments, the nests may even contain a mud damn in the front of it.  As the nest nears completion, many of the leaves are fresh and green when they are placed in the nest but after time, will dry out.  Or, they start out with brown leaves as shown and then add the green leaves later.  They will constantly replace these green leaves throughout the egg brooding period.  When pine needles are available they will often make the entire nest out of them.  In this case, the nest will be very flat and compact.  A shallow bowl will be at the back of the nest such as shown here.  Often, the eggs will be buried under the leaves.

If the nest you have is full of material and goes up around the sides of the compartment, then it is more than likely a starling nest.  If it totally fills the compartment with only a small hole to get into and material hanging out the entrance hole, then it belongs to a sparrow.  If you want to see what the nests of these pest birds look like,  Look Here

All we have are females with the white bellies at our house. How do we attract any males that are all black?

Actually, what you probably have are both females and SY males. Both Second Year males and females look very similar in coloration and are sometimes very difficult to tell apart, even for the veteran landlord. Pictures located on my, Martin Bio Page show the difference in the colorations of the different aged birds. Next year, those SY males will return as ASY males and will be all black, then you'll have your all black males at your site.

Here is a picture of a female, (on left) and an immature male, (on right).  Notice the difference in the breasts.  The male has the spots of adolescence on his.  This one is easy to tell, but some will have hardly any black feathers at all and then you'll have to use other descriptors to tell the difference such as a darker throat, black shiny cap.

We have a pair that has 4 eggs in their nest. How long will it take before the babies can fly?

It normally takes 15 or 16 days from the time the 'next to the last egg' (pippin egg) is laid till they hatch. The female starts sitting on the eggs full time when that pippin egg is laid. Then, 15 or 16 days later, the eggs will hatch, and then approx 28 to 32 days after the eggs hatch, the young should take flight or 'fledge'. That can fluctuate a day or two depending on conditions in and around the site.  This is another reason that nest checks should be done on martins.  You can keep accurate tabs on your colony and it's well being.

My birds are diving at me when I go around them. Why are they doing this?

This 'diving' or 'buzzing' is also called "strafing". The word is taken from a World War II action when planes would dive at the ground spraying opposing ground troops with bullets trying to prevent them from advancing. Your birds are doing approximately the same thing. They are seeing you as a potential predator and are diving at you while squawking at the same time. This is very common and will usually happen more as brood rearing and fledging time approaches. There really isn't anything to worry about. Usually, newer birds in the colony will do it about the time of fledging, but I've never been struck by any martin. One thing you can do is spend a little more time under the housing, and even so, you'll still have one or two birds that will do it.  It's just instinctive in them.

Do some morning walk-unders or just slowly walk under the housing and stand there and watch them, and although this may sound silly, actually talk to them. They will quickly get used to you and the sound of your voice, and the strafing will back off considerably, if not entirely. One thing I do is ignore them. They soon start ignoring me back. The whole thing depends on how much time you spend with them. If you're out and amongst them a lot, they begin to see you as part of the site and will soon go about their daily activities just as if you weren't even there.  In fact, your birds will become comfortable enough with having you around that they won't even get off the nest when you do your nest checks.  I actually have to move some of my females so I can count my eggs or see what's going on in the nest.

I've read on your page where you state that I should do nest checks.  Why?

In recent years, it has been proven that nest checks have become a very important part of keeping martins and are a very good way of keeping track of the health of your colony.  The 'old' ways of keeping purple martins are slowly, but surely, dying and educated landlords are slowly replacing these old time landlords.  Recently, many tests and studies have been done on martins and it's been proven time and again that regular site maintenance and nest checks considerably enhances the overall health and well being of your colony.  From nest checks, you can tell when nest building starts and how the progress is going, keep track of the number of eggs laid and the number of young that hatched from those eggs. 

Nest checks also help you as a landlord keep tabs on the health of the young such as, are they being fed properly, are there any problems with any of them, are they being bothered by pests like mites and/or blowflies, etc.  Predators and pests are other things you want to keep a close eye on and by doing next checks you can tell whether or not they've been there.  Also, you can keep very good tabs on how many young made it through and fledged.  These numbers are good to know and can be given to organizations that keep track of this sort of thing and they in turn can get an overall view of how martins are doing as a species.  A nest check done every 4 or 5 days can do all this and more.  And besides, they're fun to do to...ever see the eyes of a youngster light up when they look into a bird's nest and see a clutch of real live young baby birds...

And while you're at it, get yourself a Purple Martin Prognosticator from the PMCA...  It's easy to use and it'll take a lot of guess work out of the dating of your colony.  An inexpensive tool that is invaluable in hosting martins.

The 'old ways' of keeping purple martins are slowly, but surely, subsiding and as landlords become more and more educated, they realize that they have to keep their hands into their colony in order to tell what is going on.  The old adage of 'just put a house up and they will come' no longer holds true.  Too many pests, predators and problems can take hold of a colony and quickly rid it of martins.

My Nest Check Page will tell you how to do them and what to look for in more detail.

...but won't I scare my birds away by disturbing them?

No, not at all!  Yes, the birds may fly away momentarily, but they won't go far.  In fact, if you take notice, while you're doing the checks, the birds will either be flying right over head or may land on a favorite nearby perching place and watch what you're doing.  Then, as soon as you complete your checks and put the housing back up, they'll return to their duties as if nothing had ever happened.   Many landlords have never done a nest check simply because they are either afraid of scaring the birds away or because they feel the birds can take care of themselves.  I can assure you that this thinking is false and archaic and all landlords need to realize that the only way to tell the health of the colony is to do nest checks.  Don't be afraid to check your birds at least once a week, it will help both you and the birds.  (I check mine every 4 days).  They'll get to know you up close and personal and you'll get to know your birds as well.  You'll find out very quickly that purple martins aren't just your normal bird species.  They actually need and have learned to interact with humans, and in time, will get to know you and will soon start accepting you as part of the everyday happenings around their homes.  In fact, I have a lot of females that won't even get off their nests when I lower the racks and I actually have to push them aside to count the eggs.

One note here;  Although it is not necessary, it's a good idea to keep good records.  When you have young that are within a week to 10 days of fledging, (flying from the nest), then internal nest checks should be stopped.  Even though the parent birds are use to you, a sudden jerk of the housing could scare the young into jumping prematurely so if they are 22 or 24 days old, then you should stop the direct nest checks, but continue to monitor your site from a distance.  This means doing daily walk-unders and watching things from the ground.  If you have good records, you will know and be able to watch which young will fledge first, and when they finally do go, it's really fun to watch.  They in turn will get use to you and they'll peak out of their hole to watch you.

...but what about the smell from my hands?  When I do nest checks, won't the parents smell where I touched?

No!  Birds in general have very poor smell and in fact, it's terrible.  Other than specialized birds such as carrion eaters like Vultures and Condors, regular birds (Passerines) do not live by smell any more, thus their sense of smell has all but disappeared.  They now live by using their sense of site and hearing.  Regardless of what you've heard about adding any kinds of smells such as vanilla or onions to help attract martins, forget it.  You're wasting your time, and good vanilla and onions.  And as for smelling any kind of predator and the birds leaving, that is also false.  The birds left because of the predator got at them, not because of its' smell.

We have a dog that is penned in our back yard.  Will he bother the martins?

Normally, martins will pay no attention to dogs around their site, even if they are noisy.  In fact, they soon find them as a deterrent to predators and accept them as part of their site. 

However; if your dog jumps at the pole, hitting and bumping it in an attempt to try and get at them, then the martins will definitely have a problem with that.  If necessary to prevent this, make a small fence that keeps the dog away from the pole.  A little gate will allow you to get in and out easily while keeping the problem dog at bay.

Cats on the other hand are a different story.  NO birds of any kind, not even martins, will allow cats around their site or nests.

What about cutting my grass.  Won't this scare them away?

No, not at all!  Yes, they'll initially fly away when you walk or ride directly under them, but they soon return to their house.  After enough times of your mowing under them, they'll realize you aren't any threat and will actually begin to just sit there and watch you.  It's kind of funny to watch them when they sit on the house to first watch you coming and then pivot to watch you going.  And then, before too long, you'll be totally ignored, just like I am. 

But my mower is pretty loud...

No matter!  The noise doesn't bother them.  Martins are not a bit afraid of man's modern tools and toys.  In fact, I have a friend that has a son that has a motorbike and he rides all over the place and the martins don't even pay him any attention at all.  However, bumping or banging on the pole does, so try and be careful with that part of it.  

When I did a nest check, I found a female still sitting on the eggs.  What was wrong with her?

Nothing!  She has simply gotten to know and trust you enough to stay put while you're doing the nest checks.  Consider yourself lucky that your birds trust you as a non-predator enough to stay put when you are around.  That's what it's all about.  It happens to me all the time and I've actually showed many other people visiting for martin talks what it's like to have a wild bird trust you enough to stay put.  Many times during heavy brooding times the females will simply refuse to get off the nest and because I keep records, I already knew how many eggs were there from the previous nest check and will often just move on without disturbing her.  I can always catch up on the numbers with the next nest check if she isn't around.

  ...So how do I count the eggs when she's sitting on them?

Easy!  In the south, we have what they call "Corn Dogs"  They come on a long pointed stick.  I cleaned one of these up (after eating the corn dog of course) and use it to gently poke around the nest and leaves and yes, I sometimes even gently move the female so that I can look under her to make sure all things are good.  If you don't like corn dogs or can't get those sticks, then get a 1/4" diameter wooden dowel and sand one end somewhat to a point like a pencil.  Make it about 15" to 18" long.  Then you can use that to "poke around".  Martins have a tendency to bury their eggs in the leaves and nesting materials when they leave the nest and this long pointed stick makes it very easy to move things so you can see what's there.  This also helps greatly to keep big hands out of the way when doing the nest checks. 

When I did my nest checks, I found the martins had built mud dams in the front of their nests.  What's the reason for these?

There are a number of different theories on this.  Some say they're to keep the weather out and are found on westward facing gourds or compartments more so than on eastward facing ones, but when I've found them in gourds and houses, it doesn't seem to have a directional intent.  Others say it's to form a uniform bowl in the back of the nest for the eggs to set in.

However, I do have my own thoughts on the subject, and I can't prove any of this, but here they are. 

I feel they are there for a couple of different reasons:

-If you notice, they are mainly found in the 'smaller' sized house compartments and gourds more so than in the larger ones.  I use nothing but large 10" gourds and 9" minimum deep house compartments and have only found 1 or 2 mud damns in my gourds.

-Although not always, when you do find them, notice that they are usually so close to the entrance hole that they actually cut down on the size of the hole.  I feel this is their way of making it more difficult for pests and predators to either see into or enter the compartment or gourd, sort of making their very own crescent shaped entrance hole, so to speak.  If a predator can't see into the nest, then they can't see what they are trying to catch.  If the access hole size is reduced by their adding a mud dam, then some pests will have a problem getting into the nest.

Yes, they would help keep the weather out and yes, they would help keep the young in, but my own personal observations make me feel there are more reasons than just that.

When I did a nest check, I found a whole bunch of little black bugs crawling all over the nest and the baby birds.  What are these?

These are Chicken Mites and if left unattended, quite often become a major problem in martin colonies.  Mite explosions, called blooms, happen practically overnight, so it's important to not allow too much time from nest check to nest check and are another good reason for doing next checks.  Nests that are infested with these mites should be taken care of promptly or they could result in early fledging of the young or worse, their death.  Mites feed on the blood of the young and it's not a pleasant thing for a baby bird that has nowhere to go to get away from them.  Chicken mites are one reason you see so many baby Robins prematurely jump to the ground before they can fly properly.

Is there anything that can be done about them?

The control of mites and the methods used in their control is a very controversial subject and you'll get many different answers depending on who you speak with.  Here are two methods that do work to keep them under control.

One.  Nest changes.

Requirement:  Housing that is fully accessible.

This is done by removing the young and placing them in a softly lined bucket or shoe box.  Then, totally remove the nesting material from the compartment, wipe the compartment down with alcohol and then refill with new nesting material, forming a small bowl in the material where the original nest bowl was.  Some folks even replace a few green leaves back in the nest bowl.  The alcohol evaporates very quickly and the fumes are usually gone before you've finished replacing the nest material.  Then, replace the young in the bowl.  The alcohol is said to remove not only the mites in the nest box, but also any eggs that the mites may have laid there.  One suggestion here is to wrap your wrists with those little sweat bands that tennis players use and then soak them with alcohol.  This prevents the mites from crawling up your own arms and getting you.

Two. Apply 5% Sevin dust. 

As stated, the use of a poison in a wild birds nest is a very controversial subject.  However, because nest mites are such a big problem and it's been proven that 5% Sevin dust is an effective solution, testing and research is presently being done by the PMCA to see what the long term effects are on wild birds.  Depending on where and who's page you read, you're going to hear both sides of the story, so you'll have to educate yourself and then make your own decisions on whether to use it or not.

However... if you're interested and want to know "what I do", then this is it.  Being in the south, mites can become a big problem and because I have so many nests, I just don't have the time to do nest changes all day long.  So, what I do is apply a SMALL amount of 5% Sevin dust to any infected nests.  I use less than a half teaspoon of 5% Sevin dust powder and sprinkle it just inside the entrance hole on the nesting material.  When the mites travel out of the gourd to sit in the sun, they pass through the Sevin dust going in and out of the gourd and of course, get it on themselves and it will usually eliminate them within 24 hours.  Usually only one application is required per nesting season.  Sevin dust is a pesticide so please, let's not overdo it.  A little will do just as good as a lot.  Again, this is what "I Do" because I have too many nests to change out.  It works and no second treatments are ever required and the quantity I use is very controlled.

One Note Here:

DO NOT use any kind of 'off the shelf' pesticides in SPRAY CANS.  These are 'not controllable' and when used, infiltrate the entire cavity and the fumes can be lethal to young martins.  None of these spray pesticides should be used in the treatment of mites, or any other insect pest for that matter, inside "ANY" wild birds nest..

When I did my nest checks, I found an egg near the entrance hole.  All the rest of the eggs were still in the nest.  What going on?

The female martin has deemed that egg to be infertile and has removed it from the nest.  Unlike us humans, wild birds and animals do not live by emotions but instead, live by instincts, and will not waste energy on either crippled young or infertile eggs.  They will dispose of them, thus saving energy.  Although it's hard for us to understand, in the wild it can sometimes mean the difference between life and death for them.  However, not having hands to pick the egg up, the best she could do was remove it from the bowl and roll it to the front of the nest.  DO NOT replace these eggs in the nest.  They should be removed and discarded.  We think we are doing a good thing by replacing these eggs back in the nest, but in reality, we are hindering the females from doing their jobs.  They know best about what they are doing, let them do it.

Some of my young have fledged and now it seems as though there's all kinds of fighting. What's going on?

There are a couple of reasons for all this 'squabbling'. 

One, when young return to a site, they don't always make it back to their own cavity and often try to get into other nests that were not their own and the owners of that nest don't want them there, thus will try to drive them away from their compartment.

Another reason is, in just about all colonies, there are extra males that were not able to pair up with a female. These birds, known as 'floaters", often harass the young fledglings and try to drive them away from the colony. The main reason is that they don't want the young to return next spring and become competition for nesting. This is a very common occurrence around a martin colony and is part of their everyday life, so just enjoy all the noise and commotion since there isn't anything that can be done about it.

How can I insure that my fledglings are cared for once they leave the nest?

You can't.  Some things just simply have to be left up to the parent birds.  We are only able to see to it that they make it through nesting and then fledge.  From that point on, they are being taught to be wild and self sufficient by the adult birds.

My birds have all fledged and are now gone. Where did they go?

Nesting and fledging time is the most dangerous time in a martins' life. They have to nest and raise young to continue the species just like any other wildlife species and have become used to using our housing to do so. While they are in the houses, sitting on eggs and feeding and raising young, they are at the mercy of many predators and pests. There are innumerable ground and flying predators and pests that attempt to get at them at this time, so when the young are able to fly and take care of themselves, they quickly vacate the site for the safety of the air, using open power lines or radio antennas and such so they can see these predators coming from a long distance off. Remember, they are wild birds and live like this the entire rest of the year, so it's only natural that they get back to 'living' as soon as possible. A sad time for us for sure, but then isn't that why we put up the housing, to have them make more martins.

Now that the young have fledged, will the parents lay eggs again and raise a second brood of babies?

No, martins usually raise only one brood of young per year. However, should a pair lose their first clutch of eggs for some reason, some times they will lay a second clutch if it's early enough in the year, but this is only under unusual circumstances.

We had a total of 10 young fledge. How many can we expect to return next year?

According to studies done by banding young, only about 1 in 5 or 6 young will return to the same site. The main reason for this is that nature has intended the young to disperse to other sites to prevent inbreeding.  Returning young from the previous year will settle as far away as 50 to 100 miles or even further to find a new home. But don't feel too bad about this. Your birds may be populating other purple martin sites, but birds from other sites are coming to yours, thus, all sites benefit and grow.

We've got problems with Starlings/Sparrows building nests in our housing.  No matter how many times we tear them out, they rebuild.  What can we do?

One of the major problems that landlords run into is the infestation of unwanted birds in their martin housing.  Since the introduction of the European Starling and the English House Sparrow into the U.S., martin landlords are becoming more and more plagued by these pests.  Once established in your house, they will immediately build a nest in one of the compartments and then will not give it up, and no matter how many times the nest is removed, the pests simply rebuild.  This is an ongoing problem and we as landlords simply have to get a mindset that we are going to eliminate them at all costs.  If not, then they will prevent your martins from nesting and then you will lose heart and the pests will win, not only over your martins, but over you as well.

Here are a couple of things that can be done.

One, if you live in an area where you can shoot them, get yourself a good pellet rifle with a scope, (I'm out in the country and use a .410) site it in and then shoot them. 

Two, if shooting is not an option, then you will have to trap them.  There are a number of traps on the market that are made just for capturing these pests.  Check around the internet.  (Search for 'Starling and Sparrow Traps').  A number of different sources are available.  Once captured, DO NOT just drive them somewhere else and let them go.  They will often beat you back to the house.  Birds have very good homing instincts.  They must be destroyed.  Yes, it is taking a life, but sometimes we just have to take the bitter in order to enjoy the sweet.

Three, Starling Resistant Entrance Holes can be added to your houses and gourds.  They are 99% effective at preventing starlings from even entering your housing since the majority of starlings are larger than the martins.  Both of these links tell how to add them to gourds and houses.  SREH's for Gourds   SREH's on Houses

I find it very hard to kill anything and no matter how many times we remove the nest, they just rebuild it.  Wouldn't it be alright to just let them be?

Bluntly, "NO"!  If you let starlings or sparrows nest, they soon move from nest to nest destroying the martin eggs and even the young if they find them.  I will not let any bird other than martins get a foothold in any of my martin housing, 'especially starlings or sparrows'.  If they are a friendly native species, then I provide housing designed for them and then encourage them to move on.  This can be done by properly placing housing made for them and then plugging up the hole of the gourd or compartment they are using and usually they find the new housing and that problem is solved.  However, if they are either starlings or sparrows, I will do whatever I have to, to eliminate them...period.  Both of these bird species are mortal enemies of martins and will destroy eggs, kill the young and in some cases, even kill the adults.  I hate to be so blunt, but I trap and shoot these birds constantly to keep them out of my martin housing and out of my area.  I know that, in some peoples' minds they are just a 'cute little bird', but wait until you see what those cute little birds can do to a martin nest and young.  You'll quickly change your mind.  In fact, if you think they aren't much of a threat, wait until you find a starling nest that has been built right on top of hatched young martins that have been pecked to death.  If you want more details I have an entire page devoted to this problem.  Martin Pests.

What is meant by the term "Anthropomorphism".

This is a term used to describe the ascribing of human characteristics to non human things.  In this case, we tend to attach our emotional feelings to wild birds, forgetting that these are wild creatures and do not have human emotions as we might think.  They instead live primarily by instincts.  This is a study that can get very in-depth and I don't want to get into it here, but just remember, wild creatures don't show emotions as we humans do.  For some of us humans, this is very hard to understand, but it's best if we try not to get too emotionally involved about our charges.

The only place we have to put our house is near our night light.  Will this bother the martins?

No, not at all.  In fact, martins aren't the least bit afraid of man's modern technologies and innovations.  (A term I like to call technovations)  I have a night light within 20 feet of my colony and they pay it no attention at all and in fact, as can be seen here, it's one of their favorite gathering places.  Don't worry about it and put the house up.

We have martins nesting under the eaves of our porch so we bought a house for them. How do we get them to move to the house?

You don't! The birds that are nesting under the eaves of your porch are not martins but are more than likely Barn Swallows, (if it's a mud nest) a close cousin of martins. Martins are the largest member of the swallow family and nest only in man made housing east of the Rockies. Here are a few birds that are often mistaken for martins.

The Barn Swallow. These birds are smaller than the martins, have a copper colored breast and sharp "V" in their tail and usually nest in open barns, sheds and even under the eaves of porches for a lucky few. These birds will not nest in houses used for purple martins.  "Barnies" usually can be seen flying very close to the ground when feeding.  They may get a little feisty during brood rearing, but they are only trying to protect their young.  Like martins, if you spend enough time near or around their nest, they will get used to your being around and the strafing will become minimal. 

(It is often considered lucky to have barn swallows nesting around your property, especially under your porch or eaves).

Here's a link that shows a lot of details on Barn Swallows.  Barn Swallows

The Tree Swallow. Another cousin about the same size of the barn swallow that will use man made housing to nest in. These birds have pure white breasts, starting just under their beaks and covering their entire bellies. They don't nest in close knit colonies like the martins, but one pair will take over a small martin house if allowed to, defending it from all martins that want to nest there.  Housing such as Bluebird housing should be placed about 5 feet off the ground for them out of the way of your main martin house. 

Here's a link that shows a lot of details on Tree Swallows.  Tree Swallows

The Chimney Swift. This bird species is actually a member of the hummingbird family and usually nests in open topped chimneys. (Some folks call them 'Chimney Sweeps'). These little birds are all dark gray and look like little flying cigars when on the wing.  They have a very high pitched chirp when flying and feeding and will usually fly and feed in family groups.  We've had swifts in our chimney ever since we bought our home in '85.  Every year, we have to replace fallen young back on the ledge of our fireplace.

All of these birds eat insects, either from the ground, or while on the wing and are a pleasure to have around. There are more cousins around, but these are the ones most people run across. If you have them, supply proper housing for them and then enjoy them, they are all very friendly birds and a joy to watch in the summertime.

We have a pair of Tree Swallows starting to nest in our martin house.  We don't want to hurt them, what do we have to do to get them to move so we can have martins, also?

This usually happens when a new colony site is being started.  More established sites are not usually a problem because there are enough martins to fend the TS off.  But believe it or not, it's rather easy to move Tree Swallows.  There are two scenarios here, and here's how it's done:

Gourd Racks:  What you will have to do is acquire a stand-alone Shepard's hook (or pole if that's the case) that can easily be stuck in the ground.  I know for a fact that Tree Swallows love horizontally deep compartments.  I use a few Troyer Horizontal Gourds for my martins and I space them around my racks, intermixed with the other gourds.  When the Tree Swallows return, invariably they will take one of these first over all the other gourds up there.  If you have a 'new' site you are trying to get established with martins, let the TS get a nest started.  Tree Swallows love feathers and will find and begin lining their nest with them.  Once this happens and you know the nest is established, simply lower the gourd rack where they are and let them find their nest and stay in it for one night.  Next, stick a Shepard's hook in the ground in front of and as close to their nest as possible.  Take their actual nest (the whole gourd) and place it on the Shepard's hook.  Don't replace the gourd on the rack just yet.  Let them find and spend the night in the new location on the Shepard's hook.  They don't like giving up all the work they put into building their nest, so they will find it and begin using it.  A few feathers on the ground and in the entrance are great bait to get them to investigate.

The next day, raise the rack back up.  Again, let them spend the night in the gourd that has now been moved to the Shepard's hook.

The next day, simply move the Shepard's hook at least 25 feet from the rack towards the direction you ultimately want them to be and insure that it points in the same direction as it was originally on the rack.  Again, sprinkle 4 or 5 soft white feathers on the ground in front of it.  Again, they will find it and spend the night.

Finally, move the hook another 25 feet, sprinkle a couple more feathers and let them find and spend the night.

Now, lower the rack, replace the gourd (you should keep extras around just for this reason) and re-raise the rack.  

All done.  Now you can now have your TS while at the same time, having martins.

If their gourd is put in the same place the following year, many times they will return right to it and will not give you any trouble.  However, if they do decide to move into another gourd on the rack, the same procedure can be followed each time and you can have both species nesting in your yard.  Once one pair of TS takes up nesting, they will keep all other TS out of the immediate area, so you only have to deal with one pair around your racks.  No, they will not let another pair settle in your racks or house, they will drive them away.

Housing: Now, if you have housing other than gourds, the same thing can be done.  Just lower the house and close up the hole to the compartment they are using.  Put the gourd (or BB house) on the Shepard's hook, remove the actual nest from the house and place it in the gourd (or house), sprinkle a few feathers, and go from there.  Since they can't get in the closed up house, they will quickly select the new housing and, once they've spent the night in it, will follow it anywhere.  It's as simple as that.  Just make sure it is facing the same direction so they won't get disoriented.

Every summer when I cut the grass, I have martins flying all around me catching insects that my mower kicks up.  Should I put a house up for them?

No, because more than likely they're Barn Swallows.  Martins 'normally' do not feed near the ground and instead, feed high in the air.  One of the reasons "Barnies" and martins get along so well is that, not only are they cousins, but their nesting habits are different and plus, they usually feed at different altitudes, thus cutting down on competition for food.  Although I have heard 'experienced' landlords tell me of this occurrence, it is not a normal action for purple martins to follow a lawn mower.  However, if they do prove to be martins, then by all means, put up a house

When I bought my martin house, the advertising with it said things like "Control insect pests in your back yard by attracting Purple Martins" and "Purple Martins can eat 2000 mosquitoes a day".  However, I've read where other statements say that martins don't eat mosquitoes.  What's the real story?

According to J. L. Wade of Griggsville, IL., back in the 1920's, a man by the name of Joseph H. Dodson of Kankakee, Ill, supposedly had a dead martin's stomach contents analyzed by a state university.  The results were that it contained 2000 mosquitoes thus, the myth began.  However, what wasn't mentioned was that they were Salt Water Marsh Mosquitoes, a much larger variety than the ones that are pests to us.  When further investigation on the subject was done, much was found on Dodson, but nothing was found of his research.  Still to this day, that claim is boasted and this now long time myth is still used today by some house manufacturers and retailers to sell their houses and the ploy is used to attract the uneducated public to purchase their housing.  The key word in the statement is CAN.  However, recent studies have proven that they DON'T.  The statement is still used today to dupe the uneducated public into believing that, if they put a martin house up and attract martins, all their bothersome insect troubles will go away.  Not true at all.

Here are some more 'common sense' facts on the subject:

Although it is true that martins are fully capable of eating 2000 mosquitoes a day, the truth is, they simply just don't.  Studies done in the last decade on stomach contents of martins showed that less than 2% of the martins diet contained mosquitoes. Martins prefer much larger prey.  It's the same all throughout nature, the larger the prey, the more reward for the effort and energy spent catching it.  A mosquito is so small that the nutritional value of one wouldn't be worth the energy spent to catch it. 

Now, let's stop to think for a minute.

If mosquitoes hang out in heavy weeds and bushes, fly within 10 to 15 feet of the ground and if martins dislike bushes and feed anywhere from 100 to 1000 feet in the air, then the two don't cross paths, therefore, how would the martins eat the mosquitoes in your back yard?  It's very unlikely if they don't even share the same air space.  And besides that, the martins disappear in the afternoon, often not being seen until dusk, therefore; if they were eating mosquitoes, then they're eating 'someone else's mosquitoes', and not yours.

If you watch your martins sitting on your housing preening, at times you can actually see the mosquitoes pestering them just as they do us and the martins are not snapping them up for a snack.

Also, think about when the mosquitoes become the worst... just about dark when it's damp.  (Mosquitoes are primarily nocturnal).  And when do most of the bird species, including martins go to bed... just about dark.  (Purple martins are diurnal).  So, again, they don't cross paths.  As was said earlier, it was an advertising ploy to sell martin houses and it's still in use today, and since it got you to buy their house, apparently it still works...  

One more... OK.  Spring time is a very wet and damp part of the year in most regions.  This makes for many small and stagnant pools of water where mosquitoes can breed and lay eggs.  However, just about the same time martins return, these small pools often dry up and much less breeding and egg laying takes place thus, much fewer mosquitoes.  Many folks attribute this to the return of the martins when in actuality, it had nothing to do with it at all.

...and, here's one more thought.  About the same time martins return in good numbers, so do 'bats' and some species are a mosquitoes' worst nightmare.  They can often be seen flying around just about dusk and they just might be one of the reasons your mosquito population might have declined.  Bats feed at night, just when the mosquitoes are at their worst.

Now I'm not saying that they 'won't' eat mosquitoes, but I am saying that they won't go looking specifically for them.

When can we expect our martins to leave for the winter?

Parents and young will hang around the site for about a week or two after fledging.  During this time, the parents will teach the young to feed on the wing and of course, the young learn to handle flying.  Since they are wild birds, then all will revert back to living in the wild.  All will move to a local communal roost in some area with other birds and congregate before the migration. This could be a power line, a small stand of trees on an island or even a large radio antenna. Usually this area will be around a small body of fresh water. Then, one day, some small time clock rings and off they all go for points south.

One more thing.  The following link will take you to a page that will describe the everyday happenings around a martin colony.  Take a minute and read it.  See if some of the things that are described there are happening at your site too. 

The Daily Habits of Martins