Every day, I get all kinds of questions about gourds. "Where do I get them?" "How do I dry them?" "How do I prepare them for martins?" But, probably the most asked question I receive about gourds
is...
"Why do I say the gourds should be 10" in diameter for Purple Martins?"
Well, the following is my reasoning.
Gourds have been around for eons. There is also historical proof that they
were used as housing for purple martins for thousands of
years, and they still make great bird houses today. In fact, if the time is taken to properly prepare
and take care of them, gourds will literally last for many generations of
martins. It is not uncommon for gourds to last up to 20 and even 30 years if properly cared for.
For part of that question, let's look at why I believe that gourds should be at least 10" in diameter.
It's often been said that I look at things a little differently, so with that in
mind, let's stop for a minute and analyze our situation. No, no special
insight or anything like that, just a little common sense.
If we look at the bird we are trying to attract, AKA, The Purple Martin, we see it's a member of the Swallow family. However, it's not just any member of the Swallow family, it happens to be the 'largest' member of the Swallow family, averaging 8" long when an adult. Assuming an adult martin is approximately 1.4" wide and 8" long, so to house one bird, I need an area 1.4" x 8". (11.2 square inches). OK, for talking purposes, let's round that number to 11 square inches needed for one bird. Now let's carry our analysis a little further. We don't usually have only one bird in a nest, there are usually 2, a male and a female. Now my area is at 2.8" x 8". (22 square inches). But, let's go a little further, still. The whole reason for supplying nesting for the martins is so they will raise young to propagate and carry on the species. Therefore; they will need even more room. Depending on available room, a pair of martins can lay as many as 7 eggs. So how much room can 7 eggs take up? Probably not much at all. But...those eggs won't always be eggs. Hopefully, within a short time those eggs will become 7 beautiful young birds who, when at the fledgling stage, will be about the same size as their parents. Well, have you done the math yet? It comes out to 99 square inches. You have a rather large mass of birds when there is a total of 9 of them. According to many books and literature out today, compartment sizes should only be 6" wide x 6" tall x 6" deep. That's according to the folks that build aluminum houses for purple martins plus, that's what you'll find in all outdated drawings and recommendations for the compartment size for purple martins. Now, a compartment that only has 6 inch sides only has 36 square inches. You just can't fit 99 sq. in. of birds in a compartment that is only 36 sq. in. in size. This is also considered to be the reason small compartments have much smaller clutch sizes. A 10 inch gourd has 78.5 sq. in., more than twice the size of the 6" compartment.
No, it still isn't the required 99 square inches that the numbers show, but it's
far better than the 36 sq. in. from the smaller compartment. But, stop to think about it. If I have a bird that is 8" long, the last thing I would want to do is use any kind of housing
were the compartment dimensions are smaller than the base bird? Let's say for talking purposes a 6" compartment. That would be, (for
analyzation purposes), about the same as an 8 foot tall man trying to sleep in a 6 foot long box. He would never be able to stretch out.
In our case, if the bird goes into the gourd head first, it has to turn around, and in order for the bird to do that freely, it would take an area that is a minimum of 8" in diameter.
Yes, I know a martin can prop it's tail up, effectively making it shorter, but
why not give it the room it needs to stretch out. Now you know why I have problems with aluminum houses that only have 6" x 6"
compartment floors. And why do martins always choose the deeper compartments if
they are available in their housing?
I also have problems with statements made by the manufacturers of these houses stating that tests done by them show that purple martins only need compartments that are 6" x 6" x 6" to nest.
Yes, they do nest in them, but studies also show that the broods are much
smaller from these smaller compartments. It's advertising hype and is a way of using less material in the manufacture of their houses, thus saving themselves money, but at the
birds' expense. Plus, the general public, not knowing any better, takes
their word for it and thus, the smaller compartment houses persist. And, if
these manufacturer's did do testing, then they need to redo it, because it's outdated. (And I would like to see the data and the results. I bet me and my calculator would have a field day with it). That is one reason why I would never use any kind of housing that does not have the minimum space requirements of at least
8", at least in depth.
And for those that want to know, an 8" gourd has 50 sq. in. inside of it. You probably won't get the larger broods, but being circular in nature, the birds
that are there will still have enough room to be able to spread out a little.
It has been proven in recent studies that the larger the housing compartments, the larger and healthier the broods are. And here's a little different analogy. If you take a goldfish and put it in a small bowl, it will never get any bigger. But if you take that same goldfish and put it in a larger tank, then it will grow to accommodate the tank. So wouldn't it stand to reason that if I tried to fit two adult birds in a compartment that is too small
to begin with, that they will only raise as many young as will fit in the compartment.
Plus, I also feel this way. The whole purpose of my supplying housing for them is so that my birds can raise as many young as possible. After all, isn't that the way to get my colony size to increase? I want them to be comfortable with lots of room to move around, hence my feelings for 10" gourds.
Scientific testing....No! Common sense....Yes.
OK, I know that not all gourds are 10" in diameter. So, if you only have 8" gourds,
they may not meet the minimum requirements, but they do have more room
than the 6" x 6" compartment, so use them. It's just that the extra 2"
in a 10" gourd will give the birds that much extra room to move around, stretch out and relax. And, if you do happen to have an assault by a flying predator, the birds will at least have a chance to back out of the way of flailing claws.
They can't do that with the smaller compartments.
Now, one other point. I believe that 4" access ports are a must for doing nest checks in gourds. The ones
I have on my gourds make it very easy to get into the gourds to check the young, change any nesting if required and to do just about any maintenance that is required inside the gourd. I strongly suggest that these be added to your gourds. It may take you some time and effort to add them, but believe me, it's worth every minute spent doing them. When it comes time to do your nest checks or maintenance, it is so easy to just unscrew the lid and you have full access to the insides of the gourds.
Now for part two of the question, "Why Gourds?"
This is where nest occupation comes into play. It's a known fact that gourds,
offered on some form of gourd rack, have up to 100% occupancy where houses rarely have more than
50% to 70%. That's due to nest site domination by the males. Male martins will occupy and defend as many house compartments as possible in the hopes of attracting more than one female. This usually results in less occupation of the compartments, especially those with porches, thus again, less young are raised.
With gourds, this doesn't happen. The gourds are independent compartments and the male cannot usually successfully defend more than one at a time. This will mean that more birds can nest and as a result, more young can be raised. So that means if I have a 16 gourd system, then there is a very good chance that all 16 gourds will be occupied. That means I will get the most out of my nesting martins as far as the number of young are concerned. Show me an aluminum house
with the old compartment size that can make that claim. And, there is plenty of tests and data that is available to back it up.
And, are my natural gourds a lot of work? The answer is... yes, initially. But remember, this is my hobby. This is something I do to keep myself busy just like any one else that has a hobby. So, it's not really work. The birds are only here during the spring and summer. So, what do I do with myself while they are gone? If I had just an aluminum house, after I cleaned it out, nothing. But, I have
natural gourds. So I grow and harvest and dry and
clean and preserve and paint and prepare. Something I can do all year long while the birds are gone.
This way I can extend my hobby so that it lasts all year
rather than just for a few months of the year. And when the birds return in the spring, I am ready for them with nice, clean, freshly prepared gourds, ready for them to fill with lots of baby martins.
And, do I have to do this every year to every gourd? No! Once the gourds are properly prepared, all I have to do each year is clean them out, and if there is some little scratch or ding that removed the paint, all I have to do is touch up. And if I prepare a couple of gourds each year, say
10 or 20, then I can keep myself busy and enjoy my hobby throughout the year. And if I take my time and do it right, they should last me for years.
So what if someone
doesn't want to use 'natural' gourd? Then to those I say, "Go get
some plastic gourds"! There are many different versions of plastic
gourds available on the market today. However, make sure that they are at
least 9 or 10 inches in diameter. Those little 6 inch gourds that some
manufacturer's sell put you right back in the same class as the houses with only
6 inch compartments. And yes, I have many different versions of plastic
gourds at my site. But I can assure you, all are to the larger size
requirements.
Now, with naturals, if you are just starting out, then you will have to do a little more work than normal, because you have to get them ALL cleaned and prepared.
But once established, you will only need to do a few each year to continue the growth of your colony. And you too can spread out your hobby for more than just a few months out of the year.
So now, hopefully you will understand why I not only like gourds, but why I say that they should be at least 10" in diameter.
Chuck Abare
Athens, Al.