Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor
Breeding outcome in birds can be influenced by both intrinsic and extrinsic factors, which may contribute differentially to each stage of the breeding cycle. Island raptors are relatively threatened species that rely on simplified food webs and usually co‐occur with invasive species. Here, we studie...
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Online Access: | http://dx.doi.org/10.1111/ibi.13234 https://onlinelibrary.wiley.com/doi/pdf/10.1111/ibi.13234 |
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crwiley:10.1111/ibi.13234 2024-06-02T08:13:50+00:00 Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor Balza, Ulises Lois, Nicolás A. Pizzarello, Gimena Lopez, María Eugenia Lois‐Milevicich, Jimena Raya‐Rey, Andrea Fondo para la Investigación Científica y Tecnológica Wildlife Conservation Society Argentina 2023 http://dx.doi.org/10.1111/ibi.13234 https://onlinelibrary.wiley.com/doi/pdf/10.1111/ibi.13234 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Ibis volume 166, issue 2, page 504-517 ISSN 0019-1019 1474-919X journal-article 2023 crwiley https://doi.org/10.1111/ibi.13234 2024-05-03T11:36:08Z Breeding outcome in birds can be influenced by both intrinsic and extrinsic factors, which may contribute differentially to each stage of the breeding cycle. Island raptors are relatively threatened species that rely on simplified food webs and usually co‐occur with invasive species. Here, we studied a population of Striated Caracara Phalcoboenus australis in Isla de los Estados (Argentina) to understand the relative contribution of food availability, topographical features and territoriality to breeding parameters. Caracaras in the area depend on the short seasonal (i.e. pulsed) availability of seabirds for feeding their chicks. On the other hand, the recent introduction of non‐native ungulates may have led to a suboptimal breeding environment by reducing Caracara nest‐site availability within the seabird colonies via disturbance of the grassland. Using data from seven breeding seasons we analyse the abundance, the proportion of breeding individuals, the spatial structure of breeding events and the population‐level breeding performance, including chick sex ratio, to study whether the breeding ecology of this species is still shaped by marine food web pulses or could be associated with invasive herbivore disturbance. The breeding adults represented only 6–15% of the population. The spatial pattern of nest‐sites did not differ from random arrangement after considering the heterogeneous distribution of food availability. Territory identity accounted for most of the variation in clutch size and productivity, and penguin availability explained part of the variability in territory occupancy and hatching rate. The chick sex ratio was biased towards females and varied according to brood size, with the more productive territories producing 91% of males. The breeding cycle of this population is still mainly dependent upon the Rockhopper Penguin Eudyptes chrysocome food pulse and presents mixed evidence of being disrupted by invasive herbivores. The studied factors contributed differentially to the output of each ... Article in Journal/Newspaper Rockhopper penguin Wiley Online Library Argentina Ibis 166 2 504 517 |
institution |
Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Breeding outcome in birds can be influenced by both intrinsic and extrinsic factors, which may contribute differentially to each stage of the breeding cycle. Island raptors are relatively threatened species that rely on simplified food webs and usually co‐occur with invasive species. Here, we studied a population of Striated Caracara Phalcoboenus australis in Isla de los Estados (Argentina) to understand the relative contribution of food availability, topographical features and territoriality to breeding parameters. Caracaras in the area depend on the short seasonal (i.e. pulsed) availability of seabirds for feeding their chicks. On the other hand, the recent introduction of non‐native ungulates may have led to a suboptimal breeding environment by reducing Caracara nest‐site availability within the seabird colonies via disturbance of the grassland. Using data from seven breeding seasons we analyse the abundance, the proportion of breeding individuals, the spatial structure of breeding events and the population‐level breeding performance, including chick sex ratio, to study whether the breeding ecology of this species is still shaped by marine food web pulses or could be associated with invasive herbivore disturbance. The breeding adults represented only 6–15% of the population. The spatial pattern of nest‐sites did not differ from random arrangement after considering the heterogeneous distribution of food availability. Territory identity accounted for most of the variation in clutch size and productivity, and penguin availability explained part of the variability in territory occupancy and hatching rate. The chick sex ratio was biased towards females and varied according to brood size, with the more productive territories producing 91% of males. The breeding cycle of this population is still mainly dependent upon the Rockhopper Penguin Eudyptes chrysocome food pulse and presents mixed evidence of being disrupted by invasive herbivores. The studied factors contributed differentially to the output of each ... |
author2 |
Fondo para la Investigación Científica y Tecnológica Wildlife Conservation Society Argentina |
format |
Article in Journal/Newspaper |
author |
Balza, Ulises Lois, Nicolás A. Pizzarello, Gimena Lopez, María Eugenia Lois‐Milevicich, Jimena Raya‐Rey, Andrea |
spellingShingle |
Balza, Ulises Lois, Nicolás A. Pizzarello, Gimena Lopez, María Eugenia Lois‐Milevicich, Jimena Raya‐Rey, Andrea Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
author_facet |
Balza, Ulises Lois, Nicolás A. Pizzarello, Gimena Lopez, María Eugenia Lois‐Milevicich, Jimena Raya‐Rey, Andrea |
author_sort |
Balza, Ulises |
title |
Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
title_short |
Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
title_full |
Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
title_fullStr |
Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
title_full_unstemmed |
Variation in nest‐site occupancy and breeding outcome in a threatened Subantarctic raptor |
title_sort |
variation in nest‐site occupancy and breeding outcome in a threatened subantarctic raptor |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1111/ibi.13234 https://onlinelibrary.wiley.com/doi/pdf/10.1111/ibi.13234 |
geographic |
Argentina |
geographic_facet |
Argentina |
genre |
Rockhopper penguin |
genre_facet |
Rockhopper penguin |
op_source |
Ibis volume 166, issue 2, page 504-517 ISSN 0019-1019 1474-919X |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/ibi.13234 |
container_title |
Ibis |
container_volume |
166 |
container_issue |
2 |
container_start_page |
504 |
op_container_end_page |
517 |
_version_ |
1800737452676087808 |