Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex
Abstract Nest defence is a common form of parental care employed by birds to improve the survival of their offspring. Theory predicts that parents should adjust their nest defence according to the value of the brood at stake, defending more intensively broods with high survival and reproductive pros...
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crwiley:10.1111/j.1439-0310.2011.02003.x 2024-06-23T07:54:09+00:00 Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex Svagelj, Walter S. Magdalena Trivellini, María Quintana, Flavio 2011 http://dx.doi.org/10.1111/j.1439-0310.2011.02003.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1439-0310.2011.02003.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1439-0310.2011.02003.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Ethology volume 118, issue 3, page 251-259 ISSN 0179-1613 1439-0310 journal-article 2011 crwiley https://doi.org/10.1111/j.1439-0310.2011.02003.x 2024-05-31T08:11:51Z Abstract Nest defence is a common form of parental care employed by birds to improve the survival of their offspring. Theory predicts that parents should adjust their nest defence according to the value of the brood at stake, defending more intensively broods with high survival and reproductive prospects. We evaluated the influence of offspring number, offspring age, laying date and parent sex on nest‐defence intensity (NDI) of the Imperial Shag Phalacrocorax atriceps , a sexually dimorphic seabird with seasonal decline in offspring survival and very limited renesting potential. We also evaluated whether NDI was correlated within pairs and whether NDI of both members of the pair was correlated with incubation and breeding success. To elicit defensive behaviour, we simulated predation attempts using a Kelp Gull Larus dominicanus model. As predicted by theory, NDI was positively correlated with the number of offspring in the nest and offspring age. NDI during chick rearing was higher than that at early and late incubation, while no differences were found between incubation stages. Contrary to our prediction, we did not find differences in NDI according to laying date. NDI for males was higher than females, while NDI was also positively correlated within pairs. NDI was not statistically related to incubation or breeding success. These results suggest that other factors, such as laying date or parental quality and age, play a much larger role in determining the outcome and productivity of a nesting attempt. Our results provide partial support for parental investment theory; while parental defence increased with brood value according to offspring number and age, parental defence was not related to laying date, a factor strongly affecting offspring survival and recruitment probabilities in this species. Article in Journal/Newspaper Imperial Shag Phalacrocorax atriceps Wiley Online Library Ethology 118 3 251 259 |
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Wiley Online Library |
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English |
description |
Abstract Nest defence is a common form of parental care employed by birds to improve the survival of their offspring. Theory predicts that parents should adjust their nest defence according to the value of the brood at stake, defending more intensively broods with high survival and reproductive prospects. We evaluated the influence of offspring number, offspring age, laying date and parent sex on nest‐defence intensity (NDI) of the Imperial Shag Phalacrocorax atriceps , a sexually dimorphic seabird with seasonal decline in offspring survival and very limited renesting potential. We also evaluated whether NDI was correlated within pairs and whether NDI of both members of the pair was correlated with incubation and breeding success. To elicit defensive behaviour, we simulated predation attempts using a Kelp Gull Larus dominicanus model. As predicted by theory, NDI was positively correlated with the number of offspring in the nest and offspring age. NDI during chick rearing was higher than that at early and late incubation, while no differences were found between incubation stages. Contrary to our prediction, we did not find differences in NDI according to laying date. NDI for males was higher than females, while NDI was also positively correlated within pairs. NDI was not statistically related to incubation or breeding success. These results suggest that other factors, such as laying date or parental quality and age, play a much larger role in determining the outcome and productivity of a nesting attempt. Our results provide partial support for parental investment theory; while parental defence increased with brood value according to offspring number and age, parental defence was not related to laying date, a factor strongly affecting offspring survival and recruitment probabilities in this species. |
format |
Article in Journal/Newspaper |
author |
Svagelj, Walter S. Magdalena Trivellini, María Quintana, Flavio |
spellingShingle |
Svagelj, Walter S. Magdalena Trivellini, María Quintana, Flavio Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
author_facet |
Svagelj, Walter S. Magdalena Trivellini, María Quintana, Flavio |
author_sort |
Svagelj, Walter S. |
title |
Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
title_short |
Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
title_full |
Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
title_fullStr |
Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
title_full_unstemmed |
Parental Investment Theory and Nest Defence by Imperial Shags: Effects of Offspring Number, Offspring Age, Laying Date and Parent Sex |
title_sort |
parental investment theory and nest defence by imperial shags: effects of offspring number, offspring age, laying date and parent sex |
publisher |
Wiley |
publishDate |
2011 |
url |
http://dx.doi.org/10.1111/j.1439-0310.2011.02003.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1439-0310.2011.02003.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1439-0310.2011.02003.x |
genre |
Imperial Shag Phalacrocorax atriceps |
genre_facet |
Imperial Shag Phalacrocorax atriceps |
op_source |
Ethology volume 118, issue 3, page 251-259 ISSN 0179-1613 1439-0310 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1439-0310.2011.02003.x |
container_title |
Ethology |
container_volume |
118 |
container_issue |
3 |
container_start_page |
251 |
op_container_end_page |
259 |
_version_ |
1802646183349321728 |