River Bird Blog

Copyright 2007 by Richie Swanson

There’s dry-hollow knocks like an ancient-wooden clock, and then a yellow-billed cuckoo hides high in an oak, leaning, turning, and another flies up, and they blur behind leaves, and he bobs atop her, both slender like doves, grayish in cloudy light. The science says the male cuckoo reaches over the female’s shoulder, placing a twig in her bill, and the two hold it jointly until finished mating. But he hops off and dives down before I see any twig, and then she skulks forward, stares down after him and dives too, flashing rufous wings. Ka-ka-ka-ka-kow-kow-kow-kow-kowlp-kowlp-kowlp! The cuckoo utters a deliberate song vanishing swiftly from the Midwest, already gone from Oregon, Washington and British Columbia. The species declined 95% in Wisconsin 1966-1996 and continues to drop 2.5% per year in the upper Midwest, Region 3, USFWS.

During Migratory Bird Day weekend, May 11-14, 18 warblers use Aghaming, 11 which winter in mature tropical forests that are vanishing due to cattle ranching, soybeans, logging and subsistence agriculture. Nine other species from mature tropical forests also use these river-woods, including the cuckoo and scarlet tanager.

Though the yellow-billed cuckoo nests mostly in the eastern and central U.S., it winters as far south as Amazonia, and isolated populations may breed in South America. It may stagger migration and breeding dates to caterpillar outbreaks, nesting as late as September as far north as Ohio. It lays eggs in nests of other yellow-billeds and other species with similarly-colored shells. It can produce extra eggs during outbreaks of 17-year-locusts, tent caterpillars and gypsy moths. Its young fledge from nests only 17 days after egg-laying, thanks in part to feathers capable of flight a mere two hours after sheaths emerge.

Before the ban of DDT in 1972, spraying killed cuckoos outright. DDT apparently thinned eggs, and shells have not recovered their thickness yet. Tent-caterpillar control, other pesticides, may also have decreased cuckoos in some places. Many eastern and urban forests now lack the low-dense shrubs the species favors for nest sites. Cattle grazing, lower water tables, dams and inundations such as occur on the Colorado and Pecos Rivers destroy willow-cottonwood nest-sites out west. Only one percent of the species’ riparian-forest habitat in California remains. Though scientists and environmental alliances petitioned for the listing, the yellow-billed lacks Endangered Species Act protection.

Now a blazing-orange warbler lands beneath the cuckoo’s oak, the fluorescently-faced Blackburnian. It raises its flaming throat, sings crisply and clearly, zips to grapevine leaves, gleans the undersides. Blackburnians winter high in Andean forests as far south as Peru, sometimes Amazonia. They have vanished from breeding areas in the Appalachian Mountains where introduced aphids, wooly adelgids, have decimated Fraser firs and hemlocks. Blackburnians nest high in conifers, especially mature hemlocks, in spruce woods of Canda and the northeastern U.S. Like the Cape May warbler and many other songbirds, it would benefit from longer logging rotations.

Suddenly a warbler-sized bill pokes from behind a cottonwood, followed by a yellow chin and the front of a black mask topped by a white streak. The bird flits up and hover-flutters with a black necklace and heavy black streaks aside a brilliant yellow breast–a magnolia warbler.

Another hops branch-to-branch in dogwood and tips down, white under its tail, its back darkly streaked like a blackpoll’s. It slaps a worm against a stem and spins, slurping its prey, showing a sunny-yellow cap, a reddish-brown vest, a black-splashed face. The chestnut-sided warbler sings, pulsating, Please, please, pleased to meetcha!

A common yellowthroat, black-masked like a tiny-stealthy bandit, rises from slough-water to slash, shakes and wags his tail, fluffs his wings. He sings repeatedly in sun-eking-through cloud, shining atop willow and birch. Witchity-witchity-witchity! He chases a female and then another male round and round through densely tangled stems and foliage.

A prothonotary warbler flies up as if its golden plumage passes magically through bark. As a crescent moon creeps up a navy-blue horizon the next morning, he tsit-tsit-tsit-tsits above a hole in a river-birch stump. He starts singing late, well after a house wren gushes liquid gurgles, the yellow-headed blackbird kuk-koh-koh-koh-waaaaaaaaas, and bulrush gains green tones on whitening water.

The prothonotary flicks his tail in a birch-crown, swells his throat, chips toothily, and two male redstarts flash orange-and-black behind him, pecking and falling through the day’s first sun-streaks. Later, a male and female American redstart forage quietly as if paired, but I haven’t seen a female prothonotary near this hole yet, nor any female yellow-headed blackbirds in the cattails.

The yellow-heads arrived three weeks ago. Are they bachelors? Floater-males at Osprey Marsh without any harem? Maybe by the time a black-throated green or cerulean warbler sing down from a towering cottonwood, and osprey nestlings appear on their power pole, and the cuckoo settles on eggs, nature’s clock will tick off another answer.

SOURCES

Butler, Rhett A. January 9, 2006. Neotropical Realm: Environmental Profile. Mongabay.com/A Place out of Time: Tropical Rainforests and the Perils they face.

Dobkin, David S., Ehrlich, Paul R., and Wheye, David. 1988. The Decline of Eastern Songbirds. http://www.stanford.edu/group/standfordbirds/text/essays-/Eastern_Songbirds.html

Hughes, J.M. 1999. Yellow-billed Cuckoo (Coccyzus americanus). In The Birds of North America, No. 418 (A Poole and F. Gill, eds.) The Birds of North America, Inc., Philadelphia, PA.

Morse, D.H. 2004. Blackburnian Warbler (Dendroica fusca). The Birds of North American Online. (A. Poole, Ed.) Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database.

Petit, Lisa. 1998. Fiery Gem. Blackburnian Warbler: Bird of the MonthSmithsonian Migratory Bird Center. http://nationalzoo.si.edu/printpage/default.cfm.

Sauer, J.R., J.E. Hines, and J. Fallon. 2005. North American Breeding Bird Survey, Results and Analysis 1996-2005, Version 6.2, USGS, Patuxent Wildlife Research Center, Laurel Md.

Suckling, Kieran. April 11, 2000. Yellow-billed cuckoo 60 day notice. Letter to Bruce Babbit, Secretary of Interior. http://www.biologicaldiversity.org/swcbd/species-/cuckoo/60day.html