In Great Numbers

Last week I shared a video of our Austin Purple Martin Roost, where many thousands of Purple Martins soar together through the July sky before settling in for the night. These large flocks are called roosts, and eventually the birds will migrate together group by group to South America, where they will fatten up on insects during the winter before heading back to North America next year to nest once again. I went back a few days ago, this time with a functioning battery in my regular camera, to capture a series of images of the birds.

When we first arrived, the birds were still mostly in the sky.

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But as the sky darkened, the birds began to come in to land. They had only a few trees, maybe three in all, that were the choice resting spot. Other trees nearby remained empty.

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The sheer numbers of Purple Martins continue to astonish me, and the very loud zzzhhhhh sound of the birds in the trees could rival the worst summer cicada population.

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It can be tricky to find for the birds to find a place to perch as they join their companions.

roostc07-17-11.jpgJust look at how many birds eventually gather together on each branch! It amazes me the trees manage to stay upright under all that weight.

This time, there was a crowd of bird watchers gathered in the nearby mall parking lot for the occasion. They oohed and aahed, too. Most of them stayed farther back, while a few brave souls joined me by the trees. For the sake of these pictures, I got pooped on three times — thank goodness for my giant floppy hat!

Purple Martin Party

Last night I piled my family into the car to partake in the social event of the summer season — the annual mass congregation of Purple Martins. The birds gather in numbers from tens of thousands to hundreds of thousands in such roosts all over the eastern half of North America. The groups are so large that they actually can be monitored with Doppler radar. Austin is lucky enough to have a large roosting spot right here.

In a typical summer, the Purple Martins will start gathering in our area around mid-July, with birds migrating toward South America group by group, until by August they are gone, off to their winter home. However, with the extended drought we’ve been having, this is no typical summer. The birds are roosting earlier than usual, and I suspect they’ll leave earlier than usual, as well. Only the birds know how long they intend to stick around.

Most roosts can be found near water sources, as the numbers of insects are far greater there. I’m not sure why our Purple Martins roost near Highland Mall in the middle of urban central, but they’ve been going there for years. Of course, their roosting locale is also a favorite grackle and starling spot, contributing to many a person’s confusion about what kinds of birds they are seeing, especially because Austinites are used to the familiar gatherings of grackles and starlings each evening at dusk. However, the tell-tale graceful swoops and dives of the Purple Martins as they soar in the sky to find insects make them easy to distinguish from the clumsier flights of the larger dark birds, which instead forage on the ground for food.

If you watch the video above, you’ll get a sample of how utterly incredible the Austin roost is. Purple Martins, by the way, are North America’s largest swallow. And if you want to see some absolutely adorable baby Purple Martins, check out my previous Purple Martin post.