Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper )
When different introduced species across trophic levels (parasite, predator) invade island systems, they may pose significant threats to nesting birds. In this study, we measure nesting height and infer causes of offspring mortality in the critically endangered Medium Tree Finch ( Camarhynchus paupe...
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MDPI AG
2021
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ftdoajarticles:oai:doaj.org/article:aea07427748f43e39499b834cbf9d7fd 2024-01-07T09:46:12+01:00 Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) Sonia Kleindorfer Lauren K. Common Petra Sumasgutner 2021-12-01T00:00:00Z https://doi.org/10.3390/birds2040032 https://doaj.org/article/aea07427748f43e39499b834cbf9d7fd EN eng MDPI AG https://www.mdpi.com/2673-6004/2/4/32 https://doaj.org/toc/2673-6004 doi:10.3390/birds2040032 2673-6004 https://doaj.org/article/aea07427748f43e39499b834cbf9d7fd Birds, Vol 2, Iss 4, Pp 427-444 (2021) Rattus rattus Philornis downsi Short-eared Owl Smooth-billed Ani avian predators invasive species Ecology QH540-549.5 Animal culture SF1-1100 article 2021 ftdoajarticles https://doi.org/10.3390/birds2040032 2023-12-10T01:45:21Z When different introduced species across trophic levels (parasite, predator) invade island systems, they may pose significant threats to nesting birds. In this study, we measure nesting height and infer causes of offspring mortality in the critically endangered Medium Tree Finch ( Camarhynchus pauper ), an island endemic restricted to Floreana Island on the Galápagos Archipelago. Considering all nests at which a male built a nest, sang and attempted to attract a female ( n = 222 nests), only 10.4% of nests produced fledglings (5% of nests had total fledging success, 5.4% of nests had partial fledging success). Of the 123 nests chosen by a female, 18.7% produced fledglings and of 337 eggs laid, 13.4% produced fledglings. Pairing success was higher for older males, but male age did not predict nesting success. All nests with chicks were infested with avian vampire fly larvae ( Philornis downsi ). We attributed the cause of death to avian vampire fly if chicks were found dead in the nest with fly larvae or pupae (45%) present. We inferred avian (either Asio flammeus galapagoensis or Crotophaga ani ) predation (24%) if the nest was empty but dishevelled; and black rat ( Rattus rattus ) predation (20%) if the nest was empty but undamaged. According to these criteria, the highest nests were depredated by avian predators, the lowest nests by rats, and intermediate nests failed because of avian vampire fly larvae. In conclusion, there is no safe nesting height on Floreana Island under current conditions of threats from two trophic levels (introduced parasitic dipteran, introduced mammalian/avian predators; with Galápagos Short-Eared Owls being the only native predator in the system). Article in Journal/Newspaper Rattus rattus Directory of Open Access Journals: DOAJ Articles Finch ENVELOPE(167.383,167.383,-72.567,-72.567) Birds 2 4 427 444 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Rattus rattus Philornis downsi Short-eared Owl Smooth-billed Ani avian predators invasive species Ecology QH540-549.5 Animal culture SF1-1100 |
spellingShingle |
Rattus rattus Philornis downsi Short-eared Owl Smooth-billed Ani avian predators invasive species Ecology QH540-549.5 Animal culture SF1-1100 Sonia Kleindorfer Lauren K. Common Petra Sumasgutner Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
topic_facet |
Rattus rattus Philornis downsi Short-eared Owl Smooth-billed Ani avian predators invasive species Ecology QH540-549.5 Animal culture SF1-1100 |
description |
When different introduced species across trophic levels (parasite, predator) invade island systems, they may pose significant threats to nesting birds. In this study, we measure nesting height and infer causes of offspring mortality in the critically endangered Medium Tree Finch ( Camarhynchus pauper ), an island endemic restricted to Floreana Island on the Galápagos Archipelago. Considering all nests at which a male built a nest, sang and attempted to attract a female ( n = 222 nests), only 10.4% of nests produced fledglings (5% of nests had total fledging success, 5.4% of nests had partial fledging success). Of the 123 nests chosen by a female, 18.7% produced fledglings and of 337 eggs laid, 13.4% produced fledglings. Pairing success was higher for older males, but male age did not predict nesting success. All nests with chicks were infested with avian vampire fly larvae ( Philornis downsi ). We attributed the cause of death to avian vampire fly if chicks were found dead in the nest with fly larvae or pupae (45%) present. We inferred avian (either Asio flammeus galapagoensis or Crotophaga ani ) predation (24%) if the nest was empty but dishevelled; and black rat ( Rattus rattus ) predation (20%) if the nest was empty but undamaged. According to these criteria, the highest nests were depredated by avian predators, the lowest nests by rats, and intermediate nests failed because of avian vampire fly larvae. In conclusion, there is no safe nesting height on Floreana Island under current conditions of threats from two trophic levels (introduced parasitic dipteran, introduced mammalian/avian predators; with Galápagos Short-Eared Owls being the only native predator in the system). |
format |
Article in Journal/Newspaper |
author |
Sonia Kleindorfer Lauren K. Common Petra Sumasgutner |
author_facet |
Sonia Kleindorfer Lauren K. Common Petra Sumasgutner |
author_sort |
Sonia Kleindorfer |
title |
Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
title_short |
Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
title_full |
Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
title_fullStr |
Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
title_full_unstemmed |
Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch ( Camarhynchus pauper ) |
title_sort |
nesting success and nesting height in the critically endangered medium tree finch ( camarhynchus pauper ) |
publisher |
MDPI AG |
publishDate |
2021 |
url |
https://doi.org/10.3390/birds2040032 https://doaj.org/article/aea07427748f43e39499b834cbf9d7fd |
long_lat |
ENVELOPE(167.383,167.383,-72.567,-72.567) |
geographic |
Finch |
geographic_facet |
Finch |
genre |
Rattus rattus |
genre_facet |
Rattus rattus |
op_source |
Birds, Vol 2, Iss 4, Pp 427-444 (2021) |
op_relation |
https://www.mdpi.com/2673-6004/2/4/32 https://doaj.org/toc/2673-6004 doi:10.3390/birds2040032 2673-6004 https://doaj.org/article/aea07427748f43e39499b834cbf9d7fd |
op_doi |
https://doi.org/10.3390/birds2040032 |
container_title |
Birds |
container_volume |
2 |
container_issue |
4 |
container_start_page |
427 |
op_container_end_page |
444 |
_version_ |
1787427936400310272 |