You rely a lot on your ears when doing bird surveys, especially in the summertime. Thick foliage obstructs views, females are tending nests or young, and unless they are singing from an exposed perch, males may be hard to locate as well. Listening carefully for songs or call notes usually allows a patient observer to verify an identification, or recognize a behavior that provides confirmation of nesting (in my case, for a state breeding bird atlas project).
Some birds you just hardly ever see, no matter how long-fused you are waiting around checking out the shrubbery. I’ve encountered several of these enigmatic species so far this breeding season. They are disparate, unrelated birds, similar only in their sneaky, furtive ways. Here’s a (figurative) look at one of these surreptitious species. (Part 2 here)
Yellow-billed Cuckoos (Coccyzus americanus) are forest ghosts, detectable by their guttural, hollow, just-downright-strange call: ka-ka-ka-ka-kow-kow-kow-kow-kowlp-kowlp. It’s hard to tell if they are near or far. There sure seem to be a lot of them around this year. I think this may be because they had a bumper year for reproduction in 2004 due to the emergence of Brood X of the periodical cicada in this region. Cuckoos specialize in large insect prey (and hairy caterpillars like tent caterpillars and gypsy moths), responding to an abundant supply by laying more eggs. They are not obligate brood parasites like Old World cuckoos. Usually, they raise their own young, but sometimes lay their eggs in the nests of other cuckoos, and occasionally other species. Prey abundance may trigger this behavior. Sometimes. Or not. This is a bird that doesn’t easily give up its secrets.
One aspect of cuckoo development is well-documented, however. The chicks have exploding feathers. Yellow-billed Cuckoos have one of the speediest breeding cycles in the avian world, only 17 days from the eggs hitting the nest to the young ones leaving it. A week after hatching, chicks are covered in long “pin feathers,” growing feathers encased in sheaths*. All at once, the feathers begin erupting from their sheaths and presto! The bird is fully feathered in about two hours. A correspondent to Bent’s Life Histories of North American Birds reported in wonder: “This process took place with such rapidity that it reminded me of the commotion in a corn popper or a rapidly blooming flower.”
When they know they are being observed, Yellow-billed Cuckoos tend to stop moving and arch their backs to conceal their white underparts. I have a lot of territory to cover doing my atlas work, so I have yet to even spend the time really trying to see a cuckoo, much less find a nest. But bursting baby feathers! Next time I hear the wooden notes of the Rain Crow, somewhere in the woods, I may try to stalk this skulking bird.
Or at least listen for a quiet series of little explosions, the repercussions of popping plumage.
*Pin feathers look kind of like aglets, which are the things at the ends of shoelaces.