Bird Watcher's General Store

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Grackles Aim for the Pool

Dear Bird Folks,

For some strange reason, the grackles in my area have been flying over and attacking my birdbath with their droppings. The grackles seem to go out of their way to dump their waste into my birdbath. My friend says they do the same thing to her swimming pool. Why do grackles keep dropping their droppings into water?

Marcy, Marstons Mills


Why Marcy,

Why do grackles keep dropping their droppings into water? Doesn’t everybody? That does not sound so odd to me. That’s what the generous people of Boston do, only they call it the Outfall Pipe.

You might be surprised to hear this, but we get a lot of questions about grackle bombing attacks. Pools, tennis courts and big cars seem to be their favorite targets. It seems that the grackles have the same issues with opulence that many of us do. However, while most of us just complain about rich people, the grackles actually do something about it. And yes, the grackles are going out of their way to attack your friend’s pool.

Here is the odd part, the grackles aren’t hitting your birdbath with their own droppings. As strange as it may sound, they are most likely dropping another bird’s poop into your bath. Most of you are now thinking that the summer heat and traffic has finally gotten to me, but it is true. The gross stuff in your birdbath may not belong to the bird that dropped it. How is that possible, you ask? It’s a housekeeping thing. In order to keep their nests clean, most baby songbirds give off their waste in what is called a “fecal sack.” These little pouches of poop are mostly white and are encased in a tough mucous membrane. After being fed, the baby bird will turn its back to the parent and “hand” it this sack. The parent bird will then fly away with the sack and drop it a short distance away from the nest. (And I thought dealing with diapers was gross.)

It you think that is disgusting, this next bit of info will curl your toes. Instead of flying away with the waste, many birds, including bluebirds, will often eat the fecal sacks. Now there’s a pleasant thought. Perhaps that will explain why bluebirds always carry a pak of Tic-Tacs.

Most birds drop these sacks randomly as they fly, but often times grackles will target a specific dumping ground. One theory is that hundreds of years ago, before so much land was cleared, grackles only nested along the edges of lakes and rivers. Grackles, which often nest in colonies, wanted to hide their nesting sites from predators, so they would drop fecal sacks in the nearby water. Perhaps the attacks on our birdbaths and pools are a remnant of this behavior. Green tennis courts could indeed fool the birds into thinking they are small algae-filled ponds. However, I’m convinced that their attacks on big fancy cars are done purely for fun, and who can blame them for that.

Grackles are one of those birds that many people love to hate. But like so many things that we complain about, we only have ourselves to blame. The rather large grackle population is a direct result of settlers clearing land and creating perfect grackle nesting habitat. I should also point out that the much maligned grackle eats tons of nasty insects each year. And they also eat lots and lots of expensive bird seed, which is always nice.

The good news, Marcy, is that soon the nesting season will be over and these bombing attacks on your birdbath and your friend’s pool should stop. In the meantime, just keep cleaning out your birdbath water. And when you visit your friend’s pool, wear a plastic hat.