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Snakes Raid Nest Boxes Too

Dear Bird Folks,

I hope you can solve a mystery for me. Yesterday we had a nest of day-old baby chickadees in one of our birdhouses, and now they are gone. I don’t think some predator took them because the nest is undisturbed. Do adult chickadees sometimes move their babies to another nest? Could I have caused them to abandon their nest by looking into their box so often?

– Pam, Syracuse, NY


I don’t know you, Pam,

I’ve only been to Syracuse once in my life and I don’t recall ever meeting anyone named “Pam.” However, I can’t imagine that you have a face that would cause newly hatched chickadees to “abandon their nest,” especially since they are born naked, blind and flightless. There must be another explanation. You weren’t wearing that new cat-scented perfume by any chance, were you? Birds really hate that.

Each year we hear from tons of people inquiring about missing nestlings. That’s always a difficult question for us to answer because baby birds are a popular menu item for many creatures. Everything – from mammals to reptiles to other birds – enjoys the quick energy provided by pink, chubby nestlings. With such a long list of possible nest robbers, it is very difficult to pinpoint the guilty creature. Back in the 80s, there was some discussion about fitting all baby birds with LoJack,in order to track them, but that plan ended when no one wanted to reach into the predator to recover either the bird or the device.

Although difficult, it’s a bit easier to figure out who raided a birdhouse because the list of possible subjects is much shorter. Only a few creatures have the size or skills required to reach into the tiny entrance hole. And the fact that you claimed the nest was “undisturbed” makes the list even shorter.

The first suspect on the list is the dreaded, uncontrolled, domestic house cat. Cats are excellent climbers and have the dexterity needed to reach into tight nesting cavities and snatch up its contents with their deadly claws. Cats are so skillful that often they are able to drag out the little birds without disturbing the nest. If you or your neighbors have cats that roam loose, that may be your culprit.

Another creature to point a finger at is a fellow bird – the imported House Sparrow. House Sparrows aggressively compete with native birds for birdhouses. If they find an occupied box, they don’t look for another one. They simply remove the occupants. House Sparrows don’t eat the birds, they just want them gone. When a sparrow is involved it’s not unusual to find dead bird bodies scattered about nearby. Isn’t that a pleasant image? Just wait, it’s about to get creepier. The last on our list of suspects is a creature that many people don’t think of as a birdhouse robber. It is a deceptively good climber that comes and goes without a trace. And when it exits, it doesn’t leave so much as a fingerprint because it has no fingers. It never leaves dead babies lying around or disturbs the nest. It only disturbs me. I’m talking about snakes. (Cue the spooky music.)

Some species of snakes are excellent climbers and are nearly impossible to keep out of a birdhouse. Last week I was talking with a lady from Pittsburgh who constantly has Black Rat Snakes getting into her nest boxes. She says they are able to crawl up any pole, get around most baffles and will even climb up the side of her house to get to the nests. The lady asked me for a suggestion. I told her to move out of Pittsburgh.

While we are on the topic of mysterious bird disappearances, here a few other creatures that steal baby birds, but will often leave telltale signs. If you wake up one morning to find nesting material hanging out of the entrance hole to your birdhouse then you have been visited by our old pal the raccoon. If you find eggs on the ground below the entrance hole or if the eggs are still in the nest but have holes poked in them, you have an aggressive House Wren living in your neighborhood. Finally, if your baby birds are gone, the pole is knocked over, and the birdhouse is destroyed, then you have been victimized by either a bear or my wife’s driving.

No, Pam, you didn’t cause the disappearance of the baby birds by looking into your birdhouse. Birdhouses are raided all the time. You’ll probably never know what took those chicks, but there is a good chance it was a snake. As upsetting as it may be for us, baby birds are an important part of the food chain. We shouldn’t be mad at the snakes. Although, even I have to admit the thought of having a snake eating out of my birdhouse makes me a bit uncomfortable. But not nearly as uncomfortable as I’ll be if my wife finds out what I wrote about her driving.