| We extended the analysis to the five cowbird species that conform a monophyletic group in the phylogeny. |
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| One nest was parasitized after incubation had begun, and the cowbird egg in another nest did not hatch. |
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| Estimating the cost of accepting a cowbird egg was done by experimentally placing newly hatched cowbird chicks into catbird nests. |
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| When this egg-laying trick is well played, the cowbird egg hatches before the other eggs in the nest. |
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| Incubation time is short, 10 to 12 days, which allows the young cowbird to get a head start in the nest. |
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| I was sure the cowbird, a female, was targeting the phoebes, and apparently they knew it too. |
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| It may also be that parental phoebes attempted to dislodge cowbird shells and some were able to do so. |
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| Studies have shown that predation and cowbird parasitism decreases as nests are located farther away from edges and towards forest interiors. |
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| One host egg was missing following an ejection of an artificial cowbird egg. |
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| Future research should focus on such traits of cowbird relatives and on how these traits preadapted a particular lineage to become parasites. |
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| Yet, the presence of cowbird chicks is often accompanied by a reduction of the number of host chicks and fledglings. |
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| The cowbird parents tricked the vireo into raising their young. |
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| To address that, we experimentally parasitized longspur nests with real and wooden cowbird eggs to determine whether longspurs eject cowbird eggs. |
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| Model eggs were made of plaster-of-Paris from casts of real cowbird eggs and painted with acrylic paints and polyurethane to mimic real cowbird eggs. |
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| I noted the number of phoebe and cowbird eggs and nestlings at each visit. |
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| The chalk-browed mockingbird, rufous-bellied thrush and brown-and-yellow marshbird reject pure white cowbird eggs, while the rufous hornero rejects eggs according to size. |
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| They are known to attack Brown-headed Cowbirds, and the low rate of cowbird parasitization of their nests seems to indicate that their defense is effective. |
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| These warblers have no known defence against cowbird parasitism. |
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| By hatching first, the cowbird gets a head start on feeding and becomes the biggest, grabbiest nestling. |
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| Supposedly the cowbird chicks would pick parasitic botflies off the rightful nestlings. |
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| Note, however, that three of our focal savanna species are either inappropriate cowbird hosts or egg rejectors. |
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| Experiments on the responses of a rejector species to threats of predation and cowbird parasitism. |
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| As for birds, the European starling and the brown-headed cowbird are both nest parasites, Swift said. |
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| McMaster and Sealy tested the idea by comparing the amount of time yellow warbler eggs took to hatch in more than 41 nests with a cowbird egg and 26 without. |
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| Song matching appears to be a feature of antiphonal singing of Brown-headed Cowbird flight whistles. |
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| Cowbird removals are used in management of several endangered species of songbird. |
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| Cowbird nestlings were placed into nests prior to the hatching of host nestlings to simulate the shorter incubation periods characteristic of parasitic species. |
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| The Bronzed Cowbird is an obligate brood parasitic species of songbird, ranging from the southern border region of the United States as far south as Central America. |
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