Screaming Cowbird Parasitism of Nests of Solitary Caciques and Cattle Tyrants

2010 ◽  
Vol 122 (4) ◽  
pp. 795-799 ◽  
Author(s):  
Alejandro G. Di Giacomo ◽  
Bettina Mahler ◽  
Juan C. Reboreda
Keyword(s):  
Cowbird Parasitism

Nest Predation and Cowbird Parasitism Create a Demographic Sink in Wetland-Breeding Song Sparrows

The Condor ◽  
1997 ◽  
Vol 99 (3) ◽  
pp. 622-633 ◽  
Author(s):  
Christopher M. Rogers ◽  
Mary J. Taitt ◽  
Gwen Jongejan
Keyword(s):  
Nest Predation ◽  
Song Sparrows ◽  
Cowbird Parasitism

scholarly journals Brown-Headed Cowbird Parasitism on Endangered Species: Relationships with Neighboring Avian Species

2011 ◽  
Vol 70 (4) ◽  
pp. 474-482 ◽  
Author(s):  
Shannon L. Farrell ◽  
Michael L. Morrison ◽  
R. Neal Wilkins ◽  
R. Douglas Slack ◽  
Andrew J. Campomizzi
Keyword(s):  
Endangered Species ◽  
Avian Species ◽  
Species Relationships ◽  
Cowbird Parasitism

scholarly journals Eastern Bluebirds Eject Brown-Headed Cowbird Eggs

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 741-745 ◽  
Author(s):  
Brian D. Peer ◽  
Lyndon R. Hawkins ◽  
Edwin P. Steinke ◽  
Patricia Blair Bollinger ◽  
Eric K. Bollinger
Keyword(s):  
Selective Pressure ◽  
Molothrus Ater ◽  
Conspecific Brood Parasitism ◽  
Sialia Sialis ◽  
Eastern Bluebird ◽  
Egg Ejection ◽  
Cavity Nesting ◽  
Eastern Bluebirds ◽  
Cowbird Parasitism ◽  
The Relationship

Abstract The relationship between the Brown-headed Cowbird (Molothrus ater) and its cavity-nesting hosts has received little attention because of the assumption that cowbirds rarely parasitize these hosts. We tested the Eastern Bluebird (Sialia sialis), a host that is sometimes heavily parasitized by cowbirds, for egg ejection behavior. Bluebirds ejected 65% of experimentally added cowbird eggs (n  =  20), but ejected no experimentally added conspecific eggs (n  =  66). This suggests that cowbird parasitism, not conspecific brood parasitism, is the selective pressure responsible for egg ejection in this species. This level of rejection may be conservative because bluebirds nest in dark cavities, which may make cowbird eggs difficult to detect by bluebirds.

High Rates of Shiny Cowbird Parasitism on the Brown-and-yellow Marshbird Select for Complementary Host Defenses

The Condor ◽  
2013 ◽  
Vol 115 (4) ◽  
pp. 910-920 ◽  
Author(s):  
Myriam E. Mermoz ◽  
Juan C. Reboreda ◽  
Gustavo J. Fernández
Keyword(s):  
Host Defenses ◽  
Cowbird Parasitism

scholarly journals Creamy-Bellied Thrush Defenses Against Shiny Cowbird Brood Parasitism

The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 788-796 ◽  
Author(s):  
Andrea A. Astie ◽  
Juan C. Reboreda
Keyword(s):  
Brood Parasitism ◽  
Hatching Success ◽  
Simultaneous Presentation ◽  
Control Model ◽  
Nest Attendance ◽  
Chick Survival ◽  
Molothrus Bonariensis ◽  
Egg Ejection ◽  
Cowbird Parasitism ◽  
Recognition Errors

AbstractWe studied Creamy-bellied Thrush (Turdus amaurochalinus) defenses against brood parasitism by Shiny Cowbirds (Molothrus bonariensis). Shiny Cowbirds decrease the reproductive success of Creamy-bellied Thrushes, and having historical habitats and ranges that overlap, we expected that thrushes possess antiparasitic defenses. We analyzed nest attendance during prelaying, laying and incubation; responses to the presentation of a model of a female cowbird or a control species close to the nest; nest abandonment associated with parasitism; and responses to experimental parasitism with white or spotted cowbird eggs (with or without the simultaneous presentation of a female cowbird model). Nest attendance was 58%–68% during prelaying and 83%–90% during laying and incubation. Thrushes had a shorter latency in returning near the nest and visited nests more frequently when we presented the cowbird model than the control model. The frequency of abandonment of parasitized nests was low and was not temporally associated with parasitism. Thrushes ejected white eggs more frequently than spotted eggs when parasitism was associated with the presentation of the cowbird model, but there were no differences when the model was absent. Our results indicate that Creamy-bellied Thrushes recognize cowbirds as a threat and eject white but not spotted cowbird eggs. We postulate that the low impact of cowbird parasitism on thrush hatching success and chick survival and the likelihood of recognition errors when parasite eggs resemble host eggs may have prevented the evolution of egg ejection in this host.

scholarly journals Correlates of Egg Rejection in Hosts of the Brown-Headed Cowbird

The Condor ◽  
2004 ◽  
Vol 106 (3) ◽  
pp. 580-599 ◽  
Author(s):  
Brian D. Peer ◽  
Spencer G. Sealy
Keyword(s):  
Molothrus Ater ◽  
Egg Rejection ◽  
The Past ◽  
Evolutionary Equilibrium ◽  
Long Time ◽  
Cowbird Parasitism ◽  
Nest Sanitation ◽  
Evolutionary Lag ◽  
Taxonomic Affiliation ◽  
Recognition Errors

AbstractWe conducted a comparative analysis of eight potential correlates of egg rejection in hosts of the parasitic Brown-headed Cowbird (Molothrus ater) to test the evolutionary equilibrium and evolutionary lag hypotheses as explanations for the acceptance of cowbird parasitism. The analyses generally supported evolutionary lag. Historic contact with cowbirds may explain why hosts that have recently come into contact with cowbirds accept parasitism, but it does not account for acceptance by hosts with long histories of contact with cowbirds. Egg predation by hosts, nest sanitation, population size, and egg appearance were not correlated with rejection. Larger species that typically build larger nests were more likely to reject. Large hosts may have been parasitized more frequently in the past, possibly due to their more easily found nests or superiority as hosts, and as a result, may have had more opportunity to evolve rejection. Rejection was also correlated with taxonomic affiliation, suggesting that once rejection evolves it is maintained, which implies that rejection is not costly and thus argues against an evolutionary equilibrium. Not surprisingly, hosts with large bills were more likely to reject. This may be a corollary of the tendency for large hosts, which tend to have larger bills, to reject. An evolutionary equilibrium may exist for hosts with eggs that resemble cowbird eggs, depending on the costs to host reproductive success and the likelihood of committing recognition errors. Nevertheless, some hosts have been in contact with cowbirds for a long time, build large nests, have large bills, have a “favorable” phylogeny, and lay eggs that differ from cowbird eggs, yet accept cowbird parasitism. Chance may play a role in the accumulation of the necessary recombinants and mutations necessary for the evolution of rejection.Factores Correlacionados con el Rechazo de Huevos por parte de Hospederos de Molothrus aterResumen. Realizamos un análisis comparativo de ocho factores que potencialmente podrían estar correlacionados con el rechazo de huevos por parte de hospederos del parásito de cría Molothrus ater para poner a prueba las hipótesis de equilibrio evolutivo y de demora en la respuesta evolutiva propuestas para explicar la aceptación del parasitismo. Los análisis generalmente apoyaron la hipótesis de la demora en la respuesta evolutiva. El contacto histórico con Molothrus podría explicar por qué hospederos que sólo recientemente han entrado en contacto con estas aves aceptan el parasitismo, pero no explica por qué hay hospederos que tienen largas historias de contacto con el parásito y aceptan ser parasitadas. La depredación de huevos por parte del hospedero, el comportamiento de aseo del nido, el tamaño poblacional y la apariencia de los huevos no estuvieron correlacionados con el rechazo de huevos parásitos. Las especies grandes, que típicamente construyen nidos más grandes, presentaron una probabilidad más alta de rechazar huevos. Los hospederos más grandes podrían haber sido parasitados más frecuentemente en el pasado, posiblemente debido a que sus nidos se encuentran con mayor facilidad o a que son mejores hospederos y, como resultado, podrían haber tenido mayores oportunidades evolutivas para desarrollar el comportamiento de rechazar huevos. El comportamiento de rechazo también estuvo correlacionado con la filiación taxonómica, lo que sugiere que una vez que éste evoluciona se mantiene, implicando que no es costoso, lo que a su vez es un argumento en contra de la hipótesis del equilibrio evolutivo. De forma poco sorprendente, los hospederos con picos grandes fueron más propensos a rechazar huevos. Esto podría ser un corolario de la tendencia de los hospederos grandes (los cuales tienden a tener picos más grandes) a rechazar huevos. Es posible que exista un equilibrio evolutivo para los casos de hospederos que tienen huevos que se asemejan a los de Molothrus, dependiendo de los costos sobre el éxito reproductivo del hospedero y la probabilidad de cometer errores de reconocimiento. Sin embargo, algunos hospederos han estado en contacto con Molothrus por períodos prolongados, construyen nidos grandes, tienen picos grandes, tienen afinidades filogenéticas “favorables” y ponen huevos que difieren de los del parásito, y aún así aceptan el parasitismo. El azar podría jugar un papel importante en la acumulación de los recombinantes y mutaciones necesarios para que el comportamiento de rechazo pueda evolucionar.

Acceptance of Simulated Cowbird Parasitism in a Northern Population of Red-Winged Blackbirds

2012 ◽  
Vol 167 (1) ◽  
pp. 127-135 ◽  
Author(s):  
Christie-Leigh Capper ◽  
Mélanie F. Guigueno ◽  
Spencer G. Sealy
Keyword(s):  
Northern Population ◽  
Cowbird Parasitism

Parasitism of House Wren nests by Brown-headed Cowbirds: why is it so rare?

1997 ◽  
Vol 75 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Stanislav Pribil ◽  
Jaroslav Picman
Keyword(s):  
Field Experiments ◽  
Molothrus Ater ◽  
Low Frequency ◽  
Nest Material ◽  
Nest Structure ◽  
Troglodytes Aedon ◽  
House Wren ◽  
House Wrens ◽  
Nest Desertion ◽  
Cowbird Parasitism

We tested five hypotheses that may explain why House Wren (Troglodytes aedon) nests are rarely parasitized by Brown-headed Cowbirds (Molothrus ater). House Wrens may prevent parasitism in five ways: (1) by choosing to nest in cavities with small entrances (inaccessible-entrance hypothesis), (2) by restricting the size of the entrance with nest material (nest-structure hypothesis), (3) by puncturing and ejecting parasitic eggs (puncture–ejection hypothesis), (4) by burying the parasitized clutch under a new nest (egg-burial hypothesis), or (5) by abandoning the parasitized nest altogether (nest-desertion hypothesis). We tested these hypotheses in field experiments and found that (i) female cowbirds cannot enter circular entrances smaller than 38 mm in diameter, (ii) wrens prefer cavities with small entrances (inaccessible to cowbirds) to those with large entrances (accessible to cowbirds), (iii) when forced to breed in cavities with large entrances, wrens do not reduce the entrance size with nest material, (iv) despite the unusual strength of cowbird eggs, wrens are physically capable of puncture–ejecting them, (v) wrens do not puncture–eject cowbird eggs from their own nests, (vi) wrens do not abandon parasitized nests or bury the parasitized clutches under new nests. These results are consistent with the inaccessible-entrance hypothesis. We propose that additional nesting adaptations, as well as active cowbird avoidance of House Wrens, may contribute to the low frequency of cowbird parasitism.

Response of a forest-interior songbird to the threat of cowbird parasitism

1994 ◽  
Vol 47 (2) ◽  
pp. 275-280 ◽  
Author(s):  
David Mark ◽  
Bridget J. Stutchbury
Keyword(s):  
Forest Interior ◽  
Cowbird Parasitism
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