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Cowbird - Wikipedia, the free encyclopedia Cowbirds are birds belonging to the genus Molothrus in the family Icteridae. It excludes the non-brood parasitic Bay-winged Cowbird Agelaioides [formerly Molothrus] badius. The cowbird will watch for when its host lays eggs, and when the nest is left unattended, the female will come in and lay its own eggs. en.wikipedia.org /wiki/Cowbird   (249 words)

Brown-headed Cowbird - Wikipedia, the free encyclopedia The young cowbird is fed by the host parents at the expense of their own young. Brown-headed Cowbirds are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico. Brown-headed cowbird nestlings are sometimes expelled from the nest. en.wikipedia.org /wiki/Brown-headed_Cowbird   (310 words)

Cowbirds   (Site not responding. Last check: 2007-10-19) Many parasitized species routinely recognize and reject cowbird eggs (by either destroying the egg, rebuilding the nest to cover the egg, or abandoning the nest), while many others are simply inadequate as foster parents and never successfully rear cowbird chicks. In addition cowbird nestlings usually are larger and grow faster than the host's young, which enable them to garner more than their fair share of the food brought to the nest. Cowbird fledglings do not recognize their foster parents as individuals, but respond positively to all adults of their foster parents' species. www.stanfordalumni.org /birdsite/text/essays/Cowbirds.html   (1210 words)

Cowbird Parasitism It is proposed by Evans and Gates (1997) that cowbirds are attracted to distinct visible edges formed by canopy openings in the forest landscape and, secondarily, by the occurrence of a high basal area and the total vegetation volume. One reason that cowbird parasitism may be high in forested areas is that the female cowbird prefers forested areas in the morning for breeding. In Ashland, Missouri cowbird parasitism was at 59% in areas with 50% forest, 32% grassland, and 13% rowcrop. www.schools.lth5.k12.il.us /bths-east/cowbird.html   (2977 words)

Cowbirds in Nestboxes (Part 1)   (Site not responding. Last check: 2007-10-19) Cowbird eggs hatch in 9 days so a cowbird can add eggs to a nest that is already being incubated and still have their eggs hatch first. Yesterday the cowbird egg was on top of the pile and one bluebird egg was partially buried in the nest cup so she is rotating the eggs. Cowbird young have a bright red or scarlet mouth and throat lining while the young bluebird throat is orange when compared to the cowbird. www.bestofbbml.audubon-omaha.org /cowbirds.htm   (9395 words)

Cowbird Parasitism The long period of coexistence of Brown-headed Cowbirds and their grassland hosts suggests that host species may have evolved tactics, such as removal of cowbird eggs or desertion of nests, that reduce the effects of parasitism on host populations (Mayfield 1965). Cowbirds may be attracted to pasture-rich landscapes and may reach higher abundance in these than in nearby landscapes with fewer pastures. The ratio of cowbirds to hosts, visibility of nests, and availability of perches are probably not the only factors that affect frequencies of parasitism. www.npwrc.usgs.gov /resource/birds/cowbrd/disc.htm   (1499 words)

The Brown-Headed Cowbird   (Site not responding. Last check: 2007-10-19) Even as each baby cowbird grew to a size and shape entirely unlike the adopted parents, the involuntary surrogate parents never caught on and continued to feed the cowbird as one of their own. Unfortunately for the cowbird, some bird couples tapped for involuntary surrogate parenthood aren't stupid and will recognize and destroy the cowbird eggs left in their nest or abandon the nest altogether when the foreign deposit appears. It is believed that the female cowbird will try to find a nest of the same species that raised her, an example of the well-known biological principle that no good deed goes unpunished. www.firstthings.com /ftissues/ft9302/opinion/tobin.html   (1424 words)

Cowbirds Parasitized The female cowbird lays her egg quickly and leaves, returning later to destroy at least one of her host’s eggs by jabbing it with her beak and flying away with it. While cowbirds are the only North American parasitic birds "obliged" to parasitism as a way of life, there are many other species that habitually lay their eggs in other birds’; nests. Cowbirds have become a politically correct target of human prejudice, not only because of their behavior, but also because of massive destruction of forests. realindy.com /cowbird.htm   (974 words)

Birds, Familiar: Brown-headed Cowbird, Life Histories of North American Birds, A.C. Bent Cowbirds have been called monogamous, polygamous, polyandrous, and even plain promiscuous; probably any one of these terms could be applied to certain individuals under certain circumstances; but there is much evidence to indicate that the cowbird was originally monogamous and is so by preference today in most cases. Cowbirds' eggs are sometimes found in nests of birds that are wholly unfitted to become foster parents for the young, in which cases the eggs never hatch or the young never survive. Cowbirds seem to be on good terms with other flbirds and starlings, associating with them in enormous mixed flocks on their feeding grounds or roosting with them at night. home.bluemarble.net /~pqn/ch41-50/cowbird.html   (12085 words)

June 2001 Bird of the Month - Brown-Headed Cowbird Cowbirds are related to flbirds, grackles, orioles, meadowlarks and bobolink -- all of which are known at "icterids" (from the Subfamily Icterinae). Cowbird eggs have been found in the nests of at least 220 different species, but not all successfully raised the chicks. Cowbird eradication and removal programs have been implemented in some areas of the hill country and in other regions of the U.S. to help slow the decline of endangered bird species. www.passporttotexas.com /birds/jun01.html   (639 words)

cowbird. The Columbia Encyclopedia, Sixth Edition. 2001-05 Cowbirds eat seeds but feed chiefly on insects, following behind grazing cattle in order to capture the insects stirred up in this way—hence the name cowbird and the earlier name buffalo bird. Related birds are the bronzed, the California, the dwarf, the Nevada, and the red-eyed cowbirds. Cowbirds are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Icteridae. www.bartleby.com /65/co/cowbird.html   (209 words)

ScienceDaily: Parasitic Cowbirds Thrive With A Less Ruthless Strategy Than Cuckoos   (Site not responding. Last check: 2007-10-19) Berkeley - America's brown-headed cowbird and the European cuckoo are the classic parasitic birds, laying their eggs in the nests of other bird species and leaving the chick-rearing to another parent. Hauber is one of them, having studied cowbird parasitism of Eastern phoebe nests for some six years while obtaining his Ph.D. in biology from Cornell University in upstate New York, using the facilities of the Cornell Lab of Ornithology in Tompkins County. Hauber and his colleagues are pursuing other behavioral and evolutionary questions, such as what happens when two cowbird eggs are laid in the same nest, either by the same mother or by different mothers, and whether cowbird chicks ever shoulder host eggs out of the nest to obtain the optimal two nestmates. www.sciencedaily.com /releases/2004/08/040809100411.htm   (1734 words)

[No title] Because cowbirds are brood parasites that lay 30 to 80 eggs per season in the nests of other species, their abundance can pose a severe problem for many of their 200 or more host species. Cowbird parasitism is not a major conservation issue for grassland birds in Illinois; parasitism levels are significantly higher near shrubs that cowbirds can use as perches to search for nests, but even near woody vegetation, the majority of nests escape parasitism. Because cowbirds do not appear to discriminate among these unsuitable and suitable hosts, their nesting success is probably much lower than it is in forest habitats in which none of their hosts have effective defenses. www.inhs.uiuc.edu /chf/pub/surveyreports/nov-dec97/cowbird.html   (812 words)

Brown Headed Cowbird   (Site not responding. Last check: 2007-10-19) The cowbird has expanded its range from the short grass prairie of the high plains into agricultural and suburban landscapes throughout most of North America. The cowbird's preferred habitat is varied and may include prairie, savanna grassland with low or scattered trees, woodland edges, fields, pasture, orchard and residential areas. Cowbirds are, to a certain extent, dependent upon food provided by humans and livestock operations. www.gsd.harvard.edu /brc/report/26_cowbird.html   (279 words)

Science News Online (5/30/98): Stealth, Lies and Cowbirds Cowbirds are the stealth bombers of the avian world, dark shapes that whip into another species' nest just before dawn, often while the owner is away. In less than a minute, the female cowbird lays an egg for the victims to tend and feed, commonly at the expense of the rightful nestlings' lives. The cowbird species that rules North America is the brown-headed cowbird, which ranges from sea to shining sea in the United States and sweeps north through much of Canada. www.sciencenews.org /sn_arc98/5_30_98/bob1.htm   (2090 words)

Birds of Nova Scotia - Brown-headed Cowbird   (Site not responding. Last check: 2007-10-19) On finding a cowbird's egg in her nest, the rightful owner will sometimes attempt to get rid of it by adding a new, false bottom to the nest, completely covering the egg (and sometimes her own eggs) with nesting material. The cowbird is recorded as having parasitized the nests of over 250 species, at times removing the eggs of the rightful owner, presumably to give its own egg a better chance of survival. The cowbird female has dark eyes, her plumage is mainly plain, with only faint streaks on her underparts, and her bill is short and stubby. museum.gov.ns.ca /mnh/nature/nsbirds/bns0396.htm   (709 words)

BFL : BROOD PARASITES: Brown-headed Cowbird The female cowbird lays eggs at dawn; she removes (and occasionally eats) an egg of the host the day before or the day after the parasitic egg is laid. A female Brown-headed Cowbird has a long reproductive period with an extraordinarily short interval between clutches. The reproductive success of birds that suffer the presence of a cowbird chick in their nest will therefore be significantly lower than that of unparasitized conspecifics in the same population. birds.cornell.edu /bfl/speciesaccts/bnhcow.html   (876 words)

Audubon: Cowbirds and Conservation Cowbirds foraged on the insects and prairie grass seed stirred up by bison as they made their seasonal migrations north and south. In recent decades, many land managers, conservationists and citizens have argued that parasitism by Brown-headed Cowbirds is a major threat to North American songbird populations and that cowbird parasitism is responsible for the range-wide population declines currently shown in a number of songbird species, particularly neotropical migrants. Cowbirds can be common in treeless, grassland habitats and actually reach their peak abundance in such habitats in the northern Great Plains. www.audubon.org /bird/research   (2328 words)

Griffith Wildlife Biology-Cowbird Control Instead, cowbirds lay their eggs in the nests of other birds (hosts), who then raise the cowbird chick as their own. However, when a cowbird parasitizes a small species like the vireo, flycatcher, or gnatcatcher, these smaller hosts are able to raise only the cowbird and none of their own young – a short route to extinction. Since cowbirds first appeared in California about 1900, the amount of native (host) habitat has greatly decreased, while the amount of cowbird habitat (range and agricultural land, golf courses, parks, lawns) has greatly increased. www.griffithwildlife.com /cowbird.html   (478 words)

North American Cowbird Advisory Council | Introduction   (Site not responding. Last check: 2007-10-19) As a result of the Partners in Flight cowbird workshop held in Sacramento, CA, October 1997, a broadly constituted scientific advisory group was formed to synthesize existing information and construct guidelines for the management of cowbirds at local and regional levels. Because cowbird control programs have arisen locally and regionally and have operated independently for over a decade, the results of these long-term programs have only begun to be integrated and understood. The Cowbird Scientific Advisory Council will coordinate efforts to define (1) the criteria and data that should be addressed in determining the need for a cowbird management program, (2) the best methodologies for cowbird management, and (3) the criteria, data, and analyses necessary to evaluate the success of cowbird management programs. cowbird.lscf.ucsb.edu /intro/intro.html   (1107 words)

Brown-headed Cowbird   (Site not responding. Last check: 2007-10-19) Brown-headed Cowbirds are brood parasites, that is, they have completely abandoned the tasks of building nests, incubating eggs, and caring for hatchlings. The female cowbird finds these nests by watching patiently from an observation post where she can look down upon grassland species, by observing the nests of tree-nesting species while she walks quietly on the forest floor, or by crashing noisily through shrubbery with flapping wings to flush out potential victims. During migratory flights, cowbirds associate in flocks with Red-winged Blackbirds, Common Grackles, and Rusty Blackbirds, less commonly with American Robins and Eastern Meadowlarks in the East and with Brewer's Blackbirds and Yellow-headed Blackbirds in the West. www.birds.cornell.edu /BOW/BNHCOW   (973 words)

Brown-headed Cowbird The egg of the Brown-headed Cowbird is white, bluish or greenish with a fine speckling of reddish brown. Cowbird chicks usually hatch a day or two before the eggs of the host bird and grow rapidly, giving them a competitive head start. Some host species recognize and reject cowbird eggs, but many host species such as the Song Sparrow do not distinguish between their own eggs and those of the cowbird. www.wbu.com /chipperwoods/photos/cowbird.htm   (582 words)

Georgia Wildlife Web Site; birds: Molothrus ater   (Site not responding. Last check: 2007-10-19) The Brown-headed Cowbird is migratory, spending time year round in the southern United States, but occurring only during the breeding season in the northern and mountainous regions of the United States. If a host accepts the cowbird egg, the chance of raising one of its own young along with the cowbird is greatly reduced. Brown-headed Cowbird parasitism is considered to be one of the reasons for the decline of the Kirtland's Warbler, a northern species which is Federally listed as Endangered. museum.nhm.uga.edu /gawildlife/birds/Passeriformes/mater.html   (596 words)

cowbird on Encyclopedia.com COWBIRD [cowbird] New World bird of the flbird and oriole (hangnest) family. Taking back the nest; as cowbirds push some songbirds toward extinction, conservationists are debating an uncomfortable solution: killing the pests. Sunrise nest attendance and aggression by Least Bell's Vireos fail to deter cowbird parasitism. www.encyclopedia.com /html/c1/cowbird.asp   (832 words)

Brown-headed Cowbirds Consequently, cowbirds developed a breeding strategy known as "brood parasitism," in which they would lay their eggs in the nest of another species, allowing this "host" species to raise the cowbird offspring. If a host species’; population were severely affected by cowbirds, this strategy would not have worked over the long term (who would raise the cowbird young?). There are definitely cases, especially in areas where cowbirds have expanded their range due to deforestation, where host species have not developed a strategy to deal with parasitism. www.suttoncenter.org /bhco.html   (772 words)

Cowbird Parasitism   (Site not responding. Last check: 2007-10-19) We measured the frequency of cowbird parasitism of passerine species in seeded grassland, natural grassland, and cropland in studies conducted in North Dakota during 1981-1993. We speculate that much of the variation in parasitism rate among these habitats is related to the local abundance of cowbirds, to nest visibility, and to the presence of suitable perches for female cowbirds. Female cowbirds may use shrubs as perches while searching for host nests, and shrubs are more common in natural grasslands than in the other habitats we examined. www.npwrc.usgs.gov /resource/birds/cowbrd/cowbrd.htm   (398 words)

Brown-headed Cowbird Brown-headed Cowbird: Breeds throughout much of southern Canada and the U.S. Spends winters in central and southern parts of breeding range as well as in Florida. Brown-headed Cowbird: Nest parasite; four or five white eggs, lightly speckled with brown, are laid one at a time in the nest of another bird. Male Shiny Cowbird is glossy fl overall and has a purple sheen on head, back, and breast. identify.whatbird.com /obj/107/_/Brown-headed_Cowbird.aspx   (706 words)

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