Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host

The Screaming Cowbird (Molothrus rufoaxillaris) is a specialized brood parasite that primarily parasitizes the Bay-winged Cowbird, (Agelaioides badius; Screaming Cowbirds parasitize 80-100% of this species' nests). In contrast, the Shiny Cowbird (M. bonariensis) parasitizes more than 200 hosts....

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Autores principales: Mermoz, M.E., Fernández, G.J.
Formato: JOUR
Materias:
Breeding success
Brood parasitism
Brown-and-yellow Marshbird
Host specialization
Screaming Cowbird
Shiny Cowbird
Agelaioides badius
Molothrus
Molothrus bonariensis
Molothrus rufoaxillaris
Pseudoleistes virescens
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00105422_v105_n1_p63_Mermoz
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00105422_v105_n1_p63_Mermoz
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spelling todo:paper_00105422_v105_n1_p63_Mermoz2023-10-03T14:09:18Z Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host Mermoz, M.E. Fernández, G.J. Breeding success Brood parasitism Brown-and-yellow Marshbird Host specialization Screaming Cowbird Shiny Cowbird Agelaioides badius Molothrus Molothrus bonariensis Molothrus bonariensis Molothrus rufoaxillaris Molothrus rufoaxillaris Pseudoleistes virescens Pseudoleistes virescens The Screaming Cowbird (Molothrus rufoaxillaris) is a specialized brood parasite that primarily parasitizes the Bay-winged Cowbird, (Agelaioides badius; Screaming Cowbirds parasitize 80-100% of this species' nests). In contrast, the Shiny Cowbird (M. bonariensis) parasitizes more than 200 hosts. According to the differential reproductive success hypothesis, we expect that Screaming Cowbirds would have a lower reproductive success than Shiny Cowbirds when parasitizing other hosts. We assessed the breeding success of the Screaming Cowbird using an alternative host, the Brown-and-yellow Marshbird (Pseudoleistes virescens). This species is a common host of the Shiny Cowbird with 60-70% of nests parasitized, and is also regularly parasitized by the Screaming Cowbird but with lower frequency (6-20% of the nests). We compared the breeding success of Screaming and Shiny Cowbirds parasitizing this host species. No differences were found in the number of fledglings produced per egg laid between cowbird species. About 8-10% of cowbird eggs produced fledglings. The daily survival rate of Screaming Cowbird eggs was higher than daily survival rates for Shiny Cowbird eggs, but no differences were detected in the nestling daily survival rates. Moreover, we could not detect any difference in the hatching success (nestlings per egg), fledging success (fledglings per nestling), or growth rates of the two parasitic cowbird chicks. Furthermore, breeding success and growth rates of Screaming Cowbird chicks were similar to those previously reported while parasitizing the Bay-winged Cowbird. Our results are not consistent with the differential reproductive success hypothesis proposed as an explanation for the specialized parasitism of Screaming Cowbirds. Fil:Mermoz, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Fernández, G.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00105422_v105_n1_p63_Mermoz
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Breeding success
Brood parasitism
Brown-and-yellow Marshbird
Host specialization
Screaming Cowbird
Shiny Cowbird
Agelaioides badius
Molothrus
Molothrus bonariensis
Molothrus bonariensis
Molothrus rufoaxillaris
Molothrus rufoaxillaris
Pseudoleistes virescens
Pseudoleistes virescens
spellingShingle Breeding success
Brood parasitism
Brown-and-yellow Marshbird
Host specialization
Screaming Cowbird
Shiny Cowbird
Agelaioides badius
Molothrus
Molothrus bonariensis
Molothrus bonariensis
Molothrus rufoaxillaris
Molothrus rufoaxillaris
Pseudoleistes virescens
Pseudoleistes virescens
Mermoz, M.E.
Fernández, G.J.
Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
topic_facet Breeding success
Brood parasitism
Brown-and-yellow Marshbird
Host specialization
Screaming Cowbird
Shiny Cowbird
Agelaioides badius
Molothrus
Molothrus bonariensis
Molothrus bonariensis
Molothrus rufoaxillaris
Molothrus rufoaxillaris
Pseudoleistes virescens
Pseudoleistes virescens
description The Screaming Cowbird (Molothrus rufoaxillaris) is a specialized brood parasite that primarily parasitizes the Bay-winged Cowbird, (Agelaioides badius; Screaming Cowbirds parasitize 80-100% of this species' nests). In contrast, the Shiny Cowbird (M. bonariensis) parasitizes more than 200 hosts. According to the differential reproductive success hypothesis, we expect that Screaming Cowbirds would have a lower reproductive success than Shiny Cowbirds when parasitizing other hosts. We assessed the breeding success of the Screaming Cowbird using an alternative host, the Brown-and-yellow Marshbird (Pseudoleistes virescens). This species is a common host of the Shiny Cowbird with 60-70% of nests parasitized, and is also regularly parasitized by the Screaming Cowbird but with lower frequency (6-20% of the nests). We compared the breeding success of Screaming and Shiny Cowbirds parasitizing this host species. No differences were found in the number of fledglings produced per egg laid between cowbird species. About 8-10% of cowbird eggs produced fledglings. The daily survival rate of Screaming Cowbird eggs was higher than daily survival rates for Shiny Cowbird eggs, but no differences were detected in the nestling daily survival rates. Moreover, we could not detect any difference in the hatching success (nestlings per egg), fledging success (fledglings per nestling), or growth rates of the two parasitic cowbird chicks. Furthermore, breeding success and growth rates of Screaming Cowbird chicks were similar to those previously reported while parasitizing the Bay-winged Cowbird. Our results are not consistent with the differential reproductive success hypothesis proposed as an explanation for the specialized parasitism of Screaming Cowbirds.
format JOUR
author Mermoz, M.E.
Fernández, G.J.
author_facet Mermoz, M.E.
Fernández, G.J.
author_sort Mermoz, M.E.
title Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
title_short Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
title_full Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
title_fullStr Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
title_full_unstemmed Breeding success of a specialist brood parasite, the Screaming Cowbird, parasitizing an alternative host
title_sort breeding success of a specialist brood parasite, the screaming cowbird, parasitizing an alternative host
url http://hdl.handle.net/20.500.12110/paper_00105422_v105_n1_p63_Mermoz
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AT fernandezgj breedingsuccessofaspecialistbroodparasitethescreamingcowbirdparasitizinganalternativehost
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