Purple Martins and Mosquitoes
Purple Martin Myths
Throughout the years, there have been many myths and misunderstandings about purple martins that have been passed down from generation to generation. Many times these myths have been detrimental to the health and welfare of the martins. In this section, I'd like to address a few of them and give explanations as to how they were developed and the truth about them.
Martins eat 2000 mosquitoes a day:
Probably one of the biggest misconceptions that people have about purple martins is that they eat thousands of mosquitoes every day. In order for the aluminum house manufacturer's to sell their products, they came up with the statement, "Purple Martins can eat 2000 mosquitoes a day". Well, I hate to say it, but they are correct. Purple Martins CAN eat 2000 mosquitoes a day. Unfortunately, the truth is,they don't. In fact, the statement is very carefully worded so that the uneducated public believes that if they buy one of their houses and attract purple martins, then their mosquito woes are over.
Just like any other creature of nature, martins are opportunistic eaters and will take the largest and most readily available food at the time, and according to the
studies done by James R Hill III, Founder of the Purple Martin Conservation Association, mosquitoes are no where near the top of that list. Studies
done by the PMCA (and other organizations) showed that mosquitoes were less than 2% of the martins' diet.
Now let's look at some other factors
First, let's put our heads together and stop to think about something. When is it that mosquitoes become the worst? After dark! And, when do all daytime birds go to sleep? At dark! So, there's one reason the statement is false.
Second, mosquitoes like to stay close to the ground, where there's bushes to hide in and it's damp. Martins like to eat high in the air, sometimes as high as 300 feet. Another reason they don't cross paths.
Third, the favorite prey for a martin is a dragonfly, the mosquitoes' worst nightmare. Dragonflies prey on mosquito larva, therefore, the martin is actually helping the mosquito out by killing it's aggressor.
And forth, the mosquitoes hang out in your back yard, in your bushes and near your house. Martins are known to feed a rather large distance away from their home site so as not to attract the attention of predators. Again, they do nothing for your own personal welfare as far as mosquitoes are concerned.
Now this is not intended to dissuade your beliefs about martins. I'm simply presenting the facts taken from studies done on the subject. This in no way detracts from the fact that these birds are still a joy to have around. If they weren't, I wouldn't be here trying to persuade you to try and attract them.
And, if you really have a mosquito problem I highly suggest you look into some other form of control. Purple Martins are not the answer. I have a fairly good colony of martins and I also have a fairly good population of mosquitoes.
Scouts come, check out the area and then go back and get the rest of the flock:
This myth come about because people would see the first scouts return for the year and then disappear for a couple of days and then suddenly show up with more birds. However, they didn't go back to get the rest of the flock. The first martins are simply here because they are usually the most mature birds and are the first to return. Then, since they are wild birds, they are simply being wild and flying around and still roosting in trees somewhere. Once more birds start returning, (on their own), they begin congregating at their home sites and begin staying at the houses and gourds. Thus, it looks like the first scout went back to get them.
Aluminum houses are good because the aluminum doesn't harbor insect pests like wood does.
Absolutely false. True, the insects can not burrow into the aluminum to hide, but insect pests hide in the nesting materials, not in the housing materials and since ALL houses have nesting materials, then ALL houses contains insect pests, mainly mites, blowflies and fleas. Another sales gimmick directed at the un-informed public.
Just put a house or gourds up and they will come.
Unfortunately, this is no longer true. Martins have many predators and two of the worst are the European Starling and English House Sparrow. These two introduced species are very aggressive and will not only usurp the martin's cavity, but will often kill the martins in doing it. A lot of work has to go into protecting a martin colony and some of the old ways are no longer viable for keeping these birds. Today, if a potential landlord wants a colony of martins, they have to educate themselves with all the new findings and discoveries in the hobby and then follow them so that the martins will be able to raise their young without too much aggression from outside forces.
Martins can take care of themselves when other birds nest in their houses.
Again, this is false. At one time in history, this might have been true, but in recent years, European Starlings and English House Sparrows have become such strong competitors for housing that the martins are now having to constantly fight them off. Both the Starlings and Sparrow have very strong beaks and in one on one battles, the martin will lose every time. In fact, the starlings will not only destroy the eggs and kill the young, but if they are able to trap the adult in the compartment, then they will kill the adult birds also. As for the Sparrow, they will "pin" (peck small hole) in the eggs and that renders them infertile.
These two reasons alone should be enough to insure that no other birds nest in your martin housing, regardless of what anyone else tells you.
The proper size for a purple martin compartment is 6" x 6" x 6" with an entrance hole of 2".
Old school and incorrect. Once again, let's stop to think. An adult purple martin is approximately 8" long and about 2" wide. It takes two adults to make and raise a brood of young birds. If we do the numbers;
First, the adult birds can't fit properly into a 6" space (very comfortably). 8 just doesn't go into 6.
Second, if both parents are in the compartment at the same time, then that's 4" used up of the 6" width that's available. That leaves only enough room for 'one' more bird. But the average clutch for a pair of martins is approx 4 young. (Numbers taken from houses with larger compartments). Therefore; where are all the other young birds going to stay. One baby per adult pair isn't even enough to sustain the species from natural attrition. Recent research has shown that martins will double their clutch size when compartments are enlarged. Today, it's highly recommended that the small compartments in the aluminum houses be enlarged to 6" x 6" x 12" by removing the middle panel and turning two compartments into one. (Some aluminum house manufacturers will not make the change because retooling would cost money and would affect their bottom line profits).
Third, the round entrance hole is no longer the recommended type of hole to use for purple martins. Again, recent research has shown that the major majority of European Starlings cannot access the new crescent shaped entrance holes. This one discovery alone has changed the entire purple martin hobby from being a pain to being enjoyable again. No longer does the landlord have to fight off all the starlings that are constantly trying to take over his housing. With this one species held at bay, the landlord can now concentrate on the other pest species, the English House Sparrow.
And fourth, the deeper compartments allow for the martins to back out of the way when danger comes calling. With the smaller compartment sizes, the martins are in easy reach of predators and were easy meals. But with the 12" deep compartments, the martins can hide in the back and are well out of harms way. One more reason to make the change to larger compartments.
European Starlings don't like to nest in gourds because they swing.
Pure and total BUNK. The only reason starlings won't nest in gourds is if they are TOO SMALL. Starlings like a lot of room for their nests and in fact, will fill an entire five gallon bucket with nesting material just to make a nice roomy nest.
Now, if you don't believe me, a simple little test can be done. Under your martin housing, hang a small 6 or 7 inch gourd. Then, right next to it, hang a nice 10 or 11 inch gourd. Paint them both white so that there is no difference in them other than the size. Now, sit back and watch what happens. If there are starlings in the area, they'll find those gourds and 100% of the time, they'll pick that large gourd. In fact, the test can be even expanded. Add a proper sized crescent shaped SREH hole to the large gourd only and watch what happens. Even though the smaller gourd has a 2 inch entrance hole, the starlings will literally struggle to enter the larger one with the SREH.
This is also why starlings don't like the smaller compartments in many of the aluminum houses that are on the market. Small compartments keeps them out, NOT the swinging action.
So now you know the truths about a few of the myths about purple martins. Next time you talk to someone that passes on these myths, you'll know that they are probably un-informed about the subject and should be corrected. However, be forewarned. Some people hold onto these myths pretty hard because, "that's the way the old folks believed" and just simply refuse to change their thinking to modern research findings. If you like, print out this page and hand it to them if you want to reinforce your statements.
Information gathered from Woodside Gardens, The Registry of Nature Habitats, copyright 1999 -2001