I’m not conducting junco-focused field work anymore, but that doesn’t mean I’ve lost my fondness for the little guys. I was delighted this spring to find a junco nest not five meters from my front door, well-hidden in the crotch of an ornamental tree.
(Juncos usually nest on the ground, but they will occasionally nest higher.)
Since I was not studying these particular juncos For Science, I was free to interfere, so I began putting out some healthy snacks for the parents to feed their chicks. Neighbors share food, right?
With few exceptions, baby birds eat bugs. Bugs are high in fat and protein and easier to digest than seeds. When the junco chicks grow up, they will live primarily on seeds, but as chicks they need bugs; so that is what I provided.
The female junco was happy to take them, and she had a system. First, she would grab them one-by-one and take them away from the source to inspect them. She would bite each one along its length, and keep doing this until it stopped moving. (Mealworms have substantial little jaws, so killing them before feeding them to your soft babies is a good idea.) Only then would she take all of them into her bill, look around to be sure no one was watching, and fly to the nest.
It took a few days for the male junco to notice the new food source, but when he finally showed up, it was impressive.
I have spent a lot of time watching juncos, and I’ve never seen another as consistently round as this daddy junco.
He was happy to eat the insects himself, but as far as I could tell, he rarely fed the chicks. I got the impression that the female junco, whizzing back and forth with beakfuls of mealworms, did not appreciate this.
Sometime she cheeped at him, which would make him come to her, but didn’t seem to result in his feeding the chicks.
The junco chicks fledged. I was hoping to see them come get insects themselves, but being young, they hid in the vegetation—what little vegetation there is around my apartment complex—and waited for their parents to feed them.
Around this time, we started feeding a new insect to the baby birds at the wildlife rehabilitation hospital where I volunteer. I decided to offer the juncos this new creature, waxworms, for variety along with the mealworms. Waxworms are soft, unlike mealworms, and fat; they look like a treat.
The juncos liked them. A lot. They would take all the waxworms before they even looked at the mealworms.
Not long after this, I had to go out of state for some field work, so the insect supplementation perforce ceased. By the time I got back, the baby juncos would have been big enough to disperse. I never saw them again.
I thought that would be the end of my knowledge of my junco neighbors. I didn’t find a second nest, although they often do have second broods; I didn’t spy the parents hopping around searching for food for new chicks.
Then, more than a month later, I heard cheeping.
Not junco cheeping. I’ve chased juncos for too many years not to recognize a junco voice, and this wasn’t it. But it was definitely a baby bird, and definitely loud.
It was a brown-headed cowbird, the species that lays eggs in others’ nests and tricks those birds into raising cowbird babies. Juncos are a favorite target of cowbirds, and sure enough, here came my old friend the female junco.
The male junco was hanging around too, although I never saw him feed the chick. I imagine he was proud of his big, noisy baby though.
Apparently my junco neighbors had raised one brood of juncos, then a second brood of cowbird. It’s possible that there were junco chicks in that second brood, too, but I never saw one.
Cowbirds get a lot of heat for being “tricky” and “lazy,” but they’re fascinating birds with unique adaptations that allow them to pursue their odd child-rearing strategy (or lack thereof). The adults are extremely social, with complex hierarchies and courtship dances. The females are possibly the closest the bird world gets to an avian ornithologist: they have to keep track of all the nests near them and how far along their occupants are in their laying, so that the cowbird can add her own egg to the nest at exactly the right time. Essentially they are nest monitoring, just like I did, except their goal is offspring rather than a PhD.
And of course, baby cowbirds have no control over where they were laid. All they know is that they’re here now and hungry.
This particular cowbird was getting close to the age when his junco parents would stop feeding him and he would have to fend for himself. He made an effort, in between screaming for mom, to pick things up off the ground and see if they were edible.