I’m not sure where the term “bird brain” originated but it certainly came from someone who knew nothing about our feathered friends. Think about hummingbirds flying 400 miles over open ocean to get to Mexico, their hearts beating 600 times/minute, wings invisible as a propjet propeller and a GPS the size of a pinhead. That’s pretty amazing.
Closer to home, studying the nesting habits of birds shows construction skills we could never match. The hummingbird nest is a little grass hammock hanging thirty feet off the ground, rocking with every breeze to say nothing of the gale-force winds we have seen this summer.
Easier to observe are bluebirds and we have been at that for years. The Petersen box is the best venue and the nest is easy to identify; a handsome little grass affair with a few feathers from under their wings in bottom, quite different from the sloppy contraption of sparrows. Over the last few years, we have fostered dozens of nests with countless fledglings. The birds are very polite in allowing you to check on the eggs and the chicks. The female lays an egg early each morning and doesn’t start brooding until the last egg is laid. One morning, I caught the mother in the act. She didn’t fly out and when I checked later, the single egg was resting peacefully.
But there can be problems. The box is also attractive to tree swallows, house wrens, and sparrows. I routinely clean out those nests before eggs are laid, but frequently the interloper returns the same day to start over.
I have not had that scenario in my yard, but Beloved, for several years, was unsuccessful in getting bluebirds to nest in her box. After a lot of online research and talking to the Bluebird Society, we were told that hanging a weighted fishing line in front of the hole would keep everyone out but the bluebirds. That may be true but all we accomplished was catching a crow by the leg.
Not to be discouraged, the next year we hung colored plastic leis from a Polynesian restaurant from the roof and it worked; two nestings of four each for two years running. Then the invaders started ignoring our warning, so we added an American flag to the pole and had another good year.
This year we saw trouble coming, hung up suspended aluminum pie plates, little plastic windmills, and the piece de resistance, a green tennis visor obscuring the hole. We are told that wrens and the like will not enter a hole they cannot see. Success again! The second nesting has been completed and I think they have fledged.
While I have never had trouble in my yard getting nests established, this year on my second nesting I checked on the chicks the day I expected the hatching, and there they were. The activity around the box obviously increases because of the feedings. When there are four chicks, not potty trained, one would think the nest would be a horrendous mess in the two weeks or so before they fledge. Not so. The parents secrete a little mucous in which they enclose all the dropping, it hardens into a tiny white garbage bag which you can watch the parents carry away from the nest . . . many times each day.
After the chicks leave the nest, they do not return and there is rarely any residue in the bottom. The nest is removed because if there is a second nesting, it will be on top of the old nest, right at the hole where the chicks might fall out and are easy prey for sparrows and house wrens. Carolina wrens are no danger.
About a week after hatching, I noticed a marked decrease in parental attention. I thought I was not being observant enough and when I opened the box I could see a little movement in the nest, but not as much as I would have thought. Then I saw the house wren, sitting atop the box singing his tuneful, but murderous, song and I knew it wasn’t celebrating the birth of the chicks. Sure enough, they had all been killed, usually by pecking out their eyes.
Lessons to be learned: You can fool some of the birds some of the time, but you can’t fool all the birds all of the time. Second, nature has given birds brains that are extremely clever but violence sometimes still rules.
The next time you see an eastern bluebird, give a little respect to bird brains and hope they will continue to thrive, even against odds. After all, birds have been around a lot longer than humans so they must be doing something right.
– Hayden Hollingsworth
