Monday, August 7, 2017

Purple Martin Roosts

Purple Martins. Photo from Wikimedia Commons
I haven't been here in a while--it's been one thing after another, so I have barely watched birds since my last post. The most recent sideliner has been a back injury--down for 3 weeks. I am finally near caught up at work, so I am planning a birding day for my birthday next Saturday.

In the meantime, I saw a Facebook post by a friend indicating the purple martins were beginning to form one of their large pre-migration roosts over in Lakeside City, so my husband was nice enough to swing by the location of our annual roost off location off Fairway Blvd to check the status there on our way home last night. Sure enough, the lines were covered with purple martins. Usually, these are very noisy birds, but it seems when they start preparing to migrate, they get much quieter. I was watching a couple of thousand birds, but didn't hear any of them calling while they were catching bugs just before sunset.

Purple martins are one of the first of our summer birds to arrive in our area and one of the first to head south. They winter in South America, primarily in Bolivia, but also in parts of Brazil and Argentina. Although popular folklore has them as the scourge of the mosquito population, they eat few, if any, mosquitoes. If you want to control those insects, think bats. Purple martins are active high in the air during the day; mosquitoes stay low to the ground, primarily at  night. However, martins eat large numbers of insects and bugs: beetles, flies, dragonflies, spiders, grasshoppers and crickets, among others. Think about this before spraying your yard with a lot of poisons to control the insects in your yard. In Texas they have even been seen with cicadas, although they are tough to swallow.

Many people in our area put up martin houses in hopes of attracting martins to their yards. I was reading an interesting section of the Birds of North America online species account on martins about the relative merits of various houses. Martins favor wooden boxes over aluminum (probably because of the tendency of the aluminum houses to get much hotter.) However, both seem to be equally good in terms of nesting success. They also prefer houses that are larger and deeper (distance from opening to floor of the nesting area) than most commercially available houses--the deeper houses also seem to provide for better nesting success. Gourd houses provide a deeper nesting site and are well-liked by the birds. They seem to prefer nest sites 3 - 5 m from the ground (approximately 10 - 16 ft.) We think of purple martins as being dependent upon the houses we put up, but they use natural cavities and single unit bird boxes as well as the "apartment complexes" we put up.

If you decide to put up a martin house, be sure to have it up by February and keep evicting the house sparrows and starlings that will attempt to move in before the martins arrive. Then enjoy their antics over the summer.

Good birding!

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