Cowbird Round-Up

My backyard bird feeders had been out perhaps a week when I saw a bird I'd never seen caught my eye. Similar in size to a red-winged blackbird but a glossy black with a chocolate-brown head, this bird hopped along the top of our deck rail, ignoring and being ignored by the goldfinches and house finches feasting there. Upon encountering a safflower seed or oil sunflower seed, the bird would swiftly snatch up this little goodie in its long, sharp beak, then quickly flap away before any of the other birds could challenge it for the treat. I watched in amusement, wondering how the tiny finches and sparrows could possibly be perceived as a threat to a bird more than twice their size.

That was my introduction to the brown-headed cowbird. A member of the blackbird family, the brown-headed cowbird is considered a parasitic species. Its females do not nest like most other birds do, nor do the cowbirds raise their own young. Instead, the female cowbird will lay her egg in the nest of another bird, usually a small bird. The host bird occasionally recognizes that the egg in her nest is not her own and may dump it out, build another layer of nest over it, or abandon the nest for a new one. More often, however, the host bird will incubate the cowbird egg along with her own and, once hatched, feed and raise the baby cowbird as if it were her own, too.

The female host bird comes across like the world's best adoptive mother, but the truth is that she's being set up as an unwitting participant in a clear case of survival of the fittest. Cowbird nestlings hatch days earlier than most bird eggs do, giving the baby cowbird a head start on growing, taking up room in the nest, and making demands on the adoptive parent birds for food. When the host bird eggs hatch, chances are that the littlest nestlings -- or, in some instances, all the nestlings -- will be ignored as weak and puny compared to the cowbird nestling. In other words, the parents will not feed the tiny hatchlings or may even toss their own babies out of the nest in order to concentrate on the bigger, hungrier cowbird baby. This way, the survival of the cowbird species is secured without the cowbird female having to do a lick of work.

Not that cowbird females are particularly bright. Although much prettier than their male brown-headed counterparts -- they are a soft, dove-grey color -- the females are oblivious of their surroundings. I've had a female cowbird fly into our sliding glass kitchen door twice, and I've seen one perform amazing calisthenics in an attempt to feed from a hummingbird feeder. Every week, I have invariably had to release a half-dozen cowbird females from our repeating sparrow trap... one particular female three times! I lost my respect for cowbirds after that.

They are, however, federally protected by the Migratory Bird Act, although it's my understanding that in some states, they are viewed as badly as the Canada goose and rock pigeon. Still, this means that a cowbird cannot be hunted, its feathers collected, or its eggs or babies touched.

This never came into consideration until two days ago, when I was monitoring my bluebird trail and I heard a strange cheeping. Looking up at a nearby blue spruce, I noticed a small brown bird perched on the very tip, an insect held in its beak... and cheeping coming from somewhere within the tree. I watched the bird hop into the tree, then fly away to search for more insects to feed the hatchlings, wherever they were in the tree.

Curious, I walked around the spruce, only to find a little hatchling in the grass about a foot away from the tree, dead. The little bird could not have been longer than my thumb, and it certainly did not have much besides down and feather sheaths. It was too young to have fledged -- flown out of the nest -- early; by my estimates, it had a good week or so more to spend in the nest. What had happened?

Circling around the tree in search of the nest, I found another little hatchling head-down in the grass. I carefully extricated it from where it was tangled, noting that one of its legs was twisted terribly beneath it. As I lifted the little bird in my gloved hand, it feebly opened its beak as if to gape for food -- it undoubtedly heard its fellow nestlings cheeping -- then closed its eyes, its head lolling slightly to the right. It died right in my hand.

I was stunned. Two perfectly healthy-looking nestlings dead in one afternoon, on a trail I monitored daily. Had some predator gotten into the nest and scared the two babies into jumping out before they were ready to leave? After burying the little duo, I returned to the blue spruce and searched the crotch of every branch, seeking the nest out of which the babies had tumbled. J brought me a ladder so I could check the higher limbs, but no luck. Still, there were two adult birds perched in the next tree, cheeping regularly and eyeing my actions. The nest had to be somewhere.

When a few more minutes of searching proved equally fruitless, I gave up and leaned down to unlock the stepladder and fold it up. As I leaned, I caught a glimpse of fluttery movement within the spruce. I froze, then very quietly, I lifted a low branch. There, about 30 inches above the ground and perched on the exterior end of a branch, was a dainty little cup nest woven of dried grasses. It could have fit on the palm of my hand, it was so small. And nestled inside were two little baby birds.

I immediately realized what the problem was. One baby bird matched the ones I'd found on the ground: tiny, with fuzzy feathers shaded brown, grey, and blue and a soft grey-streaked white belly. The other baby bird looked like a plucked chicken, or a miniature turkey vulture, with a practically bare pink head and wings with actual feathers. It dwarfed the other bird, its wings and legs barely having enough space to fold in.

It was a cowbird baby.

It would appear that, in an effort to make itself comfortable in the cramped little nest, the cowbird baby accidentally knocked one, then two of its fellow hatchlings out of the nest. As I stood by, the adult birds zipped in, feeding both of the remaining babies repeatedly, the cowbird baby receiving more than its smaller nestmate.

At this rate, the last remaining host baby would be knocked out of the nest in a day or so. I resolved to include the nest -- which I identified through the photos J took as belonging to a chipping sparrow -- in my daily trail monitoring so that, should I find the baby chipping sparrow on the ground, I could put it back in the nest right away.

Sure enough, as I approached the nest yesterday, I witnessed the baby cowbird flutter and stretch, sending the baby chipping sparrow plummeting to the ground. I dove after the baby bird, catching him in my gloved hands and holding him close. I called for M, who came running to assist, having been forewarned about the bird-nest situation. M was in a panic -- he was sure that the little bird would only get knocked out again, and was quite against my returning it to the nest. He insisted I call the local Bird Center to let them know we were coming in with a baby bird. Experience, however, told me that if the parents were nearby -- which they were, cheeping away from the next tree -- the Bird Center would do nothing except counsel us to return the baby to its nest.

The baby chipping sparrow had other ideas.

As I slowly reached towards the nest to return the baby sparrow, the baby cowbird became agitated and hopped out of the nest and further into the tree. At the same time, the baby sparrow escaped from my hands and followed the cowbird in. M was beside himself, scrambling through the grass and reaching into the tree trying to catch the escapees, all the while reminding me that he'd told me not to return the sparrow to its nest.

I came to the front of the tree and spotted the bald little cowbird peeping out from beneath. In a blink of an eye, I had him safely in my birding bucket. The cowbird cheeped plaintively, hopping around inside the bucket, as M and I continued to search for the little sparrow. It was hopeless -- his feathers camouflaged him well, and he could not be found. Of course, I had to leave then in order to get to work on time; M volunteered to stay behind, searching for the missing baby. I recommended stepping away for a half-hour or so, allowing the little sparrow to calm down, then begin the search in a less frenzied manner. With the adult chipping sparrows nearby, surely the baby wouldn't have gone too far. I asked M to return the baby cowbird to the nest as well, despite the crampd condition, and to call me to keep me informed.

I returned home several hours later to find M still combing the tall grasses around the spruce for the baby sparrow. After checking to make sure the cowbird baby was still in the nest, I began the search as well, but called it off as the evening mosquitoes came out in full force. I promised M I'd start looking again in the morning.

This morning, much to my exasperation, the cowbird baby was gone. All there was to be seen was the empty little nest and two sparrows cheeping from the nearby tree.

As I listened, I heard a soft peep calling in return. With hopes high, I again started shifting aside the grasses, hoping to find a soft ball of fluff on the ground. Instead, I found the baby cowbird who, with wings far further developed than his nestmates, led me on a merry chase through the tall meadow. When I finally caught him 20 minutes later, I cupped him carefully in my gloves and considered my options. One, I could put him temporarily in the repeating sparrow trap. That way, we'd know where he was at all times. The fact that the adult sparrows were cheeping from the tree cancelled that -- I did not want to endanger the adults as they endeavored to feed their "baby." Two, I could find him a new home in a larger nest. With that goal in mind, I approached the playground set where Sean and Bluette, our nesting bluebirds, were in the midst of feeding their brood. The baby cowbird would have enough room in their nest, but no way would he be able to squeeze out of the cavity opening when he was finally a fledgling. I nixed that idea.

I then tried, with M's help, to feed it mealworms, as the little thing kept gaping. It spat the mealworm out twice, then just kept it in its little beak, unswallowed. I finally fished it out, not wanting the baby to choke on it.

There was only one solution left: return him to his nest.

I passed the gloves and the baby cowbird to M, since he'd had success returning the nestling yesterday. Carefully, M approached the spruce and, cooing to the cowbird that it had to stay put this time, he gently placed him in the nest. The cowbird, worn out from the morning's exercise, promptly fell asleep.

I thanked M for his help and complimented him on his soft touch. He nodded wryly, noting that he was going into the veterinary field and of course he understood animals. I reminded him then that if the cowbird left again, we would just leave it to the chipping sparrows to keep track of and raise their adopted son from wherever he was hiding.

This afternoon, as I went to install a bubbler on the bird bath, I peeked at the spruce. Sure enough, the cowbird was gone again.

I walked on, fine with the knowledge that one cowbird round-up was enough for me.