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Topic: Bronzed Cowbird

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	North American Cowbird Advisory Council \| Bibliography (Site not responding. Last check: 2007-11-02)
		Brandt, A. The rearing of a cowbird by Acadian flycatchers.
		Brown-headed cowbird parasitism on golden-winged and blue-winged warblers.
		The response of brown-headed cowbirds to simulated intruders was examined using playback of cowbird vocalizations in conjunction with a model of a male or female cowbird.
	cowbird.lscf.ucsb.edu /bibliography/bibliography.html (15711 words)

	All About Birds
		Some female cowbirds peck the other cowbird eggs before laying their own eggs, effectively reducing the number of cowbird eggs in the nest.
		The maximum number of Bronzed Cowbird eggs found in one nest was 14 in an abandoned nest.
		Bronzed Cowbird parasitism has been assumed to be a factor (along with habitat loss) responsible for decreasing populations of Altamira Orioles and Audubon’s Orioles in southern Texas.
	www.birds.cornell.edu /AllAboutBirds/BirdGuide/Bronzed_Cowbird_dtl.html (376 words)

	Cowbirds
		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.stanford.edu /group/stanfordbirds/text/essays/Cowbirds.html (1210 words)

	NPWRC :: Frequency of Egg and Nestling Destruction by Female Brown-headed Cowbirds at Grassland Nests
		Cowbird destruction of some or all host eggs or nestlings present in a nest occurred at 7 (12%) of the 57 nests: one case in each of the first three years and four in 1999 (Table 1).
		Cowbirds destroyed or removed the entire contents at one of the seven nests at which they acted as predators, compared to 12 of 19 nests for thirteen-lined ground squirrels and 20 of 33 nests for other predators (note: two nests were visited by more than one predator species).
		Cowbirds were responsible for 9% of all egg losses (16 of 169) and 24% of egg losses due to predators (16 of 66) in nests monitored by cameras.
	www.npwrc.usgs.gov /resource/birds/nestdest/?C=N;O=D (2870 words)

	issg Database: Management and Information Links for Molothrus bonariensis (Site not responding. Last check: 2007-11-02)
		Factors influencing the intensity of cowbird parasitism include the type of microhabitat nests are built in (including the level of nest concealment and the structural diversity of vegetation); forest bird nests in cleared areas may be more vulnerable to cowbird parasitism.
		Cowbird removal resulted in a strong increase in the reproductive output of the brushfinch (with 16 brushfinch fledglings in 2003, compared to only 5 in 2002).
		Finally, cowbird egg removal was discouraged after preliminary trials showed it was difficult to reliably discriminate between the polymorphic brushfinch egg and the polymorphic cowbird egg.
	www.issg.org /database/species/management_info.asp?si=312&fr=1&sts= (1694 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).
		In the Texas hill country, cowbirds have contributed to the decline of endangered fl-capped vireos and golden-cheeked warblers.
		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)

	Bronzed Cowbird
		Bronzed Cowbird females are dull fl, won't show much or any neck ruff and have a orange-brown eye.
		Bronzed Cowbirds commonly feed and roost in large flocks and are frequent visitors to bird feeders.
		The Bronzed Cowbird inhabits pastures, roadside thickets, ranches, parks and orchards.
	www.shawcreekbirdsupply.com /bronzed_cowbird_info.htm (315 words)

	The Nature Conservancy in Texas - Fort Hood - Brown-headed cowbird research and management
		Brown-headed cowbirds are nest parasites, which is to say they construct no nests of their own, but instead lay eggs in the nests of other bird species.
		Cowbirds have greatly expanded their numbers and range over the past century in response to landscape changes related to cattle grazing and urbanization.
		Recent cowbird-related research projects have included an assessment of the range expansion of bronzed cowbirds (also nest parasites), impact of cowbird control on fl-capped vireo nest success and population growth, and a comparative assessment of the efficiency and effectiveness of shooting versus trapping in controlling cowbirds.
	nature.org /wherewework/northamerica/states/texas/science/art16439.html (307 words)

	The Firefly Forest - Bronzed Cowbird
		Bronzed Cowbirds (Molothrus aeneus) are common here in Tucson during the spring and summer.
		Bronzed Cowbirds are mainly found in Mexico and Central America, but some of them migrate into the southwestern United States in order to breed.
		Bronzed Cowbirds are brood parasites, and the females will surreptitiously lay their eggs in the nests of a variety of different bird species such as orioles (Icterus species).
	fireflyforest.net /firefly/2006/04/28/bronzed-cowbird (125 words)

	Blackbirds & Orioles
		Cowbirds lay their eggs in the nests of other birds, leaving the unwitting hosts to hatch the eggs and feed the young.
		Cowbirds are seldom seen in natural desert areas in winter, when they mostly forage in agricultural land; but in the breeding season, Brown-headed Cowbirds and Bronzed Cowbirds infiltrate the desert (and most other habitats), seeking nests to parasitize.
		The Bronzed Cowbird may lay 1 pale blue-green egg per day for several weeks; the female may pierce the eggs of its host while depositing her eggs.
	www.desertmuseum.org /books/nhsd_blackbirds_orioles.html (1139 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)

	Bronzed Cowbirds Arrive (Site not responding. Last check: 2007-11-02)
		For, this was a Bronzed Cowbird, sometimes known as the Red-eyed Cowbird.
		And like its northern relative the Brown-headed Cowbird, this bird is a "brood parasite." The female lays her eggs in the nests of a wide variety of other bird species, which then incubate the cowbird's eggs and raise the nestlings to maturity, often to the detriment of their own nestlings.
		Bronzed Cowbirds are distributed from southern Texas and New Mexico through Mexico to El Salvador and Honduras.
	www.backyardnature.net /yucatan/cowbirdb.htm (510 words)

	Cowbird eggs in nestboxes
		Bronzed cowbirds tend to be in partially open habitats with scattered trees or scrub and pastures.
		Also, Cowbird's eyes open around Day 2 (about 4 days earlier than a bluebird nestling), so they are better equipped to detect the presence of their adopted parents and position and beg more effectively to receive priority for feeding.
		Thus Cowbirds do pose a threat to the survival of some species whose nests they regularly parasitize, especially those that nest near forest edges, close to open country preferred by cowbirds.
	www.sialis.org /cowbirds.htm (1687 words)

	Cowbirds
		Worse, female cowbirds have been observed ejecting nestlings from unparasitized nests, a behavior which may function in inducing potential hosts to attempt a second nest subject to parasitism by the cowbird.
		Bronzed Cowbirds were once considered a South Texas rarity but now occur commonly across much of the southwest.
		Given the large number of nests that a single cowbird female may parasitize or disrupt each year, it is not surprising that these expanding cowbird populations have been implicated in causing the extirpation of some songbird species from many areas, and the near extinction of others.
	www.saaudubon.org /articles/scully_cowbirds.html (762 words)

	Brown-headed Cowbird (Site not responding. Last check: 2007-11-02)
		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.
		Shiny Cowbird males are glossy fl with purple or purplish blue on the head, neck, breast, and upper back and greenish blue on the wings.
	www.birds.cornell.edu /BOW/BNHCOW (973 words)

	Intermediate frequencies of egg ejection by Northern Mockingbirds (Mimus polyglottos) sympatric with two cowbird ...
		Mockingbirds ejected 69% of model Bronzed Cowbird eggs, indicating that contrary to previous evidence Northern Mockingbirds eject Bronzed Cowbirds eggs at a high frequency.
		Bronzed Cowbird eggs were ejected faster than Brown-headed Cowbird eggs (1.3 and 2.1 days, respectively).
		Many hosts, particularly those of the Brownheaded Cowbird, may be in evolutionary lag having only recently become exposed to parasitism without adequate time for the necessary mutations to arise and egg ejection to evolve (Rothstein 1975a).
	www.findarticles.com /p/articles/mi_qa3793/is_200207/ai_n9136879 (958 words)

	bird132abs
		Responses of Scissor-Tailed Flycatchers (Tyrannus forficatus) to Experimental Cowbird Parasitism
		Twenty of 21 bronzed cowbird eggs were rejected an average of 3 days (range 1-11 days) after they were placed into nests, and all 20 brown-headed cowbird eggs were rejected after an average of 2 days (range 1-4 days).
		Three bronzed cowbird eggs were rejected after more than 5 days, which suggests that rejection frequencies in some studies have been underestimated because most researchers generally use 5 days as a cutoff for the length of time to eject parasitic eggs.
	www.cognizantcommunication.com /filecabinet/Bird/bird132abs.html (1266 words)

	Georgia Wildlife Web Site; birds: Molothrus ater (Site not responding. Last check: 2007-11-02)
		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.
		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.
		The female Bronzed Cowbird is variable in color but darker than the Brown-headed Cowbird female, and also has reddish eyes.
	museum.nhm.uga.edu /gawildlife/birds/passeriformes/mater.html (596 words)

	Bronzed Cowbird Range Map
		The Bronzed Cowbird is a year-round resident from extreme southeastern California, southern Arizona, New Mexico and Texas south through central Mexico to Panama.
		The Bronzed Cowbird inhabits mostly open country with occasional tree patches or large tall shrubs.
		It prefers a humid, hot climate, often in areas where cattle are grazed and is common in areas of human habitation.
	www.shawcreekbirdsupply.com /bronzed_cowbird_map.htm (59 words)

	Invasion Biology Introduced Species Summary Project - Columbia University
		Neither the Shiny Cowbird nor the Bronzed Cowbird have the kind of expansive range of the Brown-headed Cowbird.
		In Texas there is concern about cowbird parasitism affecting the endangered Black-capped Vireo, and in the Sierra Nevada there is concern about cowbird parasitism affecting populations of certain species of flycatchers and vireos.
		Others, like the authors of a 1997 Audubon paper on Brown-headed Cowbirds, argue that reports of their threat to local species are greatly exaggerated, and even that Brown-headed Cowbirds actually saw a population drop in the mid-1990s.
	www.columbia.edu /itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Molothrus_ater.htm (756 words)

	Sighting Record for Utah
		It was on the grass mulling around with the other cowbirds, then it flew to the golf course grass, then back to the top of a telephone pole (where I observed it in the scope), then it flew away.
		Brown-headed Cowbird: (The bird was with a male and a female Brown-headed Cowbird which made for a good comparison) The eye was reddish-orange not fl.
		Shiny Cowbird: This bird isn't likely to be here and it is even smaller in size and has an even straighter bill than the Black-headed Cowbird.
	www.utahbirds.org /RecCom/2002/2002_15.htm (306 words)

	issg Database: Management and Information Links for Molothrus bonariensis (Site not responding. Last check: 2007-11-02)
		A study of the endangered pale-headed brushfinch (Atlapetes pallidiceps) in Ecuador, however, revealed land use to be a major factor determining the impact of cowbird parasitism.
		Host eggs must be clearly distinguishable from cowbird eggs.
		Observations of Shiny Cowbird in the United States of America.
	www.issg.org /database/species/management_info.asp?si=312&fr=1&sts= (1694 words)

	1998 Altamira Oriole Project ~ Conservation Projects ~ Conventions ~ American Birding Association
		This brood parasite may have driven other orioles from the area, and we have determined that Bronzed Cowbirds also affect Altamira Oriole nesting success.
		We have confirmed that Bronzed Cowbirds can successfully enter Altamira Oriole nests, by waiting until the orioles are away from the nest site.
		Cowbird control may be eventually needed, but habitat restoration and improvement techniques should first be continued and expanded.
	www.americanbirding.org /mtgs/conventions/projects/1998conservation.html (508 words)

	FATE OF GRACKLE (QUISCALUS SPP.) DEFENSES IN THE ABSENCE OF BROOD PARASITISM: IMPLICATIONS FOR LONG-TERM PARASITE-HOST ... (Site not responding. Last check: 2007-11-02)
		Neither Bronzed Cowbird (Molothrus aeneus) nor Brown-headed Cowbird (M. ater) parasitism was recorded in 797 Great-tailed Grackle (Q. mexicanus) nests.
		Cross-fostered Bronzed Cowbird nestlings, but not Brown-headed Cowbird nestlings, fledged from Great-tailed Grackle nests, indicating that Brown-headed Cowbird parasitism does not select for rejection in these grackles.
		Great-tailed Crackle populations sympatric and allopatric with Bronzed Cowbirds rejected 100% of model cowbird eggs.
	www.findarticles.com /p/articles/mi_qa3793/is_200410/ai_n9434473 (936 words)

	Dr. Peer: Research
		Avian brood parasites such as the Brown-headed Cowbird lay their eggs in the nests of other birds and rely on these hosts to raise their offspring.
		Responses of Scissor-tailed Flycatchers to experimental cowbird parasitism.
		Fate of grackle defenses in the absence of brood parasitism: Implications for long-term brood parasite-host coevolution.
	www.wiu.edu /biology/personnel/peer/research.html (596 words)

	Birds of the Upper Texas Coast - Bronzed Cowbird
		Recent discussions with birders here and in Louisiana make me believe that I've been over looking it and that it is likely more common here than I thought.
		In The Spoonbill there were three reports of Bronzed Cowbirds for the one year period that I checked.
		Bronzed Cowbirds are usually in flocks of Great-tailed Grackle.
	www.texasbirding.net /birds/bronzed.htm (231 words)

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