Last week I received an e-mail from Juanita Pressley in Lubec. She and her husband, David, had seen and photographed a yellow-billed cuckoo in an apple tree on their property.
“My bird book says their range is southern Canada to Mexico. Local in California; winters in Argentina…it has some flying to do to get there before winter,” Juanita noted, adding, “We had never seen one before; are they rarely seen in this area?”
Maine is home to two types of cuckoos: the black-billed cuckoo and the yellow-billed cuckoo. Of these two, the black-billed is common throughout the state, while populations of the yellow-billed are concentrated in southern Maine and along the coast. Sightings farther Down East and inland often do occur during migration.
Although Juanita and David had never before seen a yellow-billed cuckoo in their location, it’s quite possible the bird (or one of its brethren) could have been there all along. The “Birds of North America” species account describes it as “furtive, retiring, and watchful by nature. Skulking behavior when perched; deliberately avoids movement when observers are present. Usually perches with back arched and body held low to conceal white breast and belly. Moves quietly along branches; disappears quickly into foliage when disturbed.”
I think the point has been made; this is one secretive bird.
The last few quotes above seemed tailored to describe the photograph of the bird Juanita sent me. In it, the cuckoo is perched within a thick tangle of small branches and twigs; it appears to be looking over its shoulder, frozen in place, as if shocked to be caught on camera.
In addition to its peculiar “skulking” nature, the yellow-billed cuckoo (and cuckoos in general) has a number of other unusual and bizarre traits.
For instance, it takes a mere 17 days – from the start of incubation, no less – for a young yellow-billed cuckoo to fledge from the nest. According to the BNA, this time span is among the shortest recorded for any species of bird.
Many other birds are born either naked or covered in down, with their actual body and flight feathers appearing in an ordered, regular pattern over days or weeks. However, a young cuckoo resembles a porcupine; it is covered with bristly feather sheaths, which, at six or seven days of life, burst open – and the nestling is suddenly fully feathered.
A cuckoos’ breeding schedule seems to coincide with outbreaks of certain insect species, especially caterpillars. Cuckoos absolutely feast on caterpillars; one bird was observed to eat 40 gypsy moth caterpillars in 15 minutes, as well as 47 forest tent caterpillars within six minutes. Examining a dead yellow-billed cuckoo, one ornithologist counted 325 fall webworms in the bird’s stomach.
Many of the caterpillars eaten by cuckoos have sharp spines, which become embedded in the bird’s stomach lining. Eventually these spines accumulate and begin impeding digestion. At this point, incredibly, the stomach lining is shed and regurgitated in a pellet, along with the spines – and the bird is none the worse for wear.
Black-billed and yellow-billed cuckoos will incubate and brood their own eggs and young, but sometimes they practice brood parasitism. Sneaky and quick, a female cuckoo will lay her eggs in another cuckoo’s nest, or even in other bird species’ nests, such as a robins, catbirds and wood thrushes. Young cuckoos raised in these hosts’ nests still retain the ability to recognize, and mate with, their own kind, as well as sing their own songs, despite having grown up hearing the vastly different songs of their foster parents.
As fascinating and adept at survival as yellow-billed cuckoos are, according to the BNA, their future is uncertain. Large portions of their populations have become extirpated in the West and they are no longer thought to exist in British Columbia, Washington, Oregon and possibly Nevada. In California, breeding birds declined from 15,000 pairs to 30 pairs in less than 100 years. This is thought to be the result of destruction of their preferred riparian habitat, as well as pesticide use.
Hopefully, the same fate does not await them here in the East.
BDN bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net
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