Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests
Most studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unpar...
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2006
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00048038_v123_n1_p23_Astie http://hdl.handle.net/20.500.12110/paper_00048038_v123_n1_p23_Astie |
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paper:paper_00048038_v123_n1_p23_Astie2023-06-08T14:29:38Z Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests Astié, Andrea Alejandra Reboreda, Juan Carlos Brood parasitism Creamy-bellied Thrush Egg punctures Molothrus bonariensis Shiny Cowbird Turdus amaurochalinus brood parasitism damage egg host-parasite interaction reproductive cost Molothrus Molothrus bonariensis Turdus amaurochalinus Most studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter "thrush"), as well as the costs of Shiny Cowbird eggs and chicks in this host's nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest-1. Number of host eggs punctured was positively associated with intensity of parasitism. The host's eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying. © The American Ornithologists' Union, 2006. Fil:Astié, A.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Reboreda, J.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2006 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00048038_v123_n1_p23_Astie http://hdl.handle.net/20.500.12110/paper_00048038_v123_n1_p23_Astie |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Brood parasitism Creamy-bellied Thrush Egg punctures Molothrus bonariensis Shiny Cowbird Turdus amaurochalinus brood parasitism damage egg host-parasite interaction reproductive cost Molothrus Molothrus bonariensis Turdus amaurochalinus |
| spellingShingle |
Brood parasitism Creamy-bellied Thrush Egg punctures Molothrus bonariensis Shiny Cowbird Turdus amaurochalinus brood parasitism damage egg host-parasite interaction reproductive cost Molothrus Molothrus bonariensis Turdus amaurochalinus Astié, Andrea Alejandra Reboreda, Juan Carlos Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| topic_facet |
Brood parasitism Creamy-bellied Thrush Egg punctures Molothrus bonariensis Shiny Cowbird Turdus amaurochalinus brood parasitism damage egg host-parasite interaction reproductive cost Molothrus Molothrus bonariensis Turdus amaurochalinus |
| description |
Most studies on cowbird parasitism have focused on its effects on parasitized nests, whereas few have considered the costs at nests that cowbirds visit but at which they do not lay eggs. Shiny Cowbirds (Molothrus bonariensis) peck and puncture host eggs both in nests where they lay eggs and in unparasitized nests. We analyzed the effect of egg punctures in unparasitized and parasitized nests of a large host, the Creamy-bellied Thrush (Turdus amaurochalinus; hereafter "thrush"), as well as the costs of Shiny Cowbird eggs and chicks in this host's nests. We determined thrush egg survival, hatching success, and chick survival in successful nests, and nest survival during the egg and nestling stages. Frequency of parasitism was 60%, and its intensity 1.6 ± 0.1 eggs nest-1. Number of host eggs punctured was positively associated with intensity of parasitism. The host's eggs were frequently punctured in parasitized nests (71%) and in unparasitized nests (42%). Egg punctures reduced the number of eggs at hatching in 23% and 49% of unparasitized and parasitized nests, respectively. Nests with egg punctures had a lower survival rate than nests without them, but nest survival was not associated with parasitism. Presence of a Shiny Cowbird egg was associated with a decrease in the hatching success of host eggs, but presence of a Shiny Cowbird chick did not have any detrimental effect on either the survival and growth rate of host chicks in successful nests or the survival of the whole nest. Our results show that egg punctures were the primary determinant of thrush reproductive success. Consequently, comparison of unparasitized and parasitized nests gives an incomplete estimation of the effects of Shiny Cowbirds on host reproductive success, because the cost of egg punctures is also important in nests where there is no Shiny Cowbird egg laying. © The American Ornithologists' Union, 2006. |
| author |
Astié, Andrea Alejandra Reboreda, Juan Carlos |
| author_facet |
Astié, Andrea Alejandra Reboreda, Juan Carlos |
| author_sort |
Astié, Andrea Alejandra |
| title |
Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| title_short |
Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| title_full |
Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| title_fullStr |
Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| title_full_unstemmed |
Costs of egg punctures and parasitism by Shiny Cowbirds (Molothrus bonariensis) at Creamy-bellied Thrush (Turdus amaurochalinus) nests |
| title_sort |
costs of egg punctures and parasitism by shiny cowbirds (molothrus bonariensis) at creamy-bellied thrush (turdus amaurochalinus) nests |
| publishDate |
2006 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00048038_v123_n1_p23_Astie http://hdl.handle.net/20.500.12110/paper_00048038_v123_n1_p23_Astie |
| work_keys_str_mv |
AT astieandreaalejandra costsofeggpuncturesandparasitismbyshinycowbirdsmolothrusbonariensisatcreamybelliedthrushturdusamaurochalinusnests AT reboredajuancarlos costsofeggpuncturesandparasitismbyshinycowbirdsmolothrusbonariensisatcreamybelliedthrushturdusamaurochalinusnests |
| _version_ |
1768543113089908736 |