Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa
Summary Low-latitude penguins naturally breed in burrows dug in guano. This affords them a buffered environment that remains cool and humid, reducing the risk of hyperthermia while on land. As a conservation strategy, several versions of artificial housing units have been trialled at various breedin...
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Online Access: | http://dx.doi.org/10.1017/s0959270922000351 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0959270922000351 |
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crcambridgeupr:10.1017/s0959270922000351 2024-06-23T07:51:48+00:00 Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa Welman, Shaun Pichegru, Lorien 2022 http://dx.doi.org/10.1017/s0959270922000351 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0959270922000351 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0 Bird Conservation International volume 33 ISSN 0959-2709 1474-0001 journal-article 2022 crcambridgeupr https://doi.org/10.1017/s0959270922000351 2024-05-29T08:08:28Z Summary Low-latitude penguins naturally breed in burrows dug in guano. This affords them a buffered environment that remains cool and humid, reducing the risk of hyperthermia while on land. As a conservation strategy, several versions of artificial housing units have been trialled at various breeding sites of African Penguins ( Spheniscus demersus ) around South Africa, where former guano exploitation forced many penguins to breed in exposed surface nests. While some units yielded a positive effect on breeding success by providing protection against predation, none of them have effectively mitigated the risk of heat stress in penguins or their eggs. Here, we investigated the microclimate of a recent double-layered design of ceramic artificial nests and compared that to natural burrows, exposed surface nests, and commonly used cement pipe nests, in austral summer 2021 on Bird Island, South Africa. We also recorded penguin behaviour during the hottest period at each of these nest types using remote camera traps to determine the onset of heat stress (panting). Double-layered ceramic nests out-performed all other nest types, including natural burrows, by remaining cooler throughout the day, with temperatures never exceeding 36.7°C. By contrast, all other nest types had multiple episodes where temperatures exceeded 40°C. Double-layered ceramic nests also maintained constant levels of high humidity (relative humidity [RH] >70%) throughout our study, whereas low humidity levels were observed in surface nests (RH ≈ 60%) and cement nests (RH <50%) during midday heat. We observed penguins panting at temperatures of 25°C in nest boxes, and at 22°C in exposed surface nests. This suggests that heat stress in African Penguins may occur much sooner than anticipated and that they are particularly vulnerable to hyperthermia as climate change-related global warming progresses. Fortunately, we are encouraged by the capacity of double-layered ceramic nest boxes to buffer environmental extremes and maintain suitable breeding ... Article in Journal/Newspaper Bird Island Cambridge University Press Austral Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) Burrows ENVELOPE(163.650,163.650,-74.300,-74.300) Guano ENVELOPE(141.604,141.604,-66.775,-66.775) Bird Conservation International 1 9 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Summary Low-latitude penguins naturally breed in burrows dug in guano. This affords them a buffered environment that remains cool and humid, reducing the risk of hyperthermia while on land. As a conservation strategy, several versions of artificial housing units have been trialled at various breeding sites of African Penguins ( Spheniscus demersus ) around South Africa, where former guano exploitation forced many penguins to breed in exposed surface nests. While some units yielded a positive effect on breeding success by providing protection against predation, none of them have effectively mitigated the risk of heat stress in penguins or their eggs. Here, we investigated the microclimate of a recent double-layered design of ceramic artificial nests and compared that to natural burrows, exposed surface nests, and commonly used cement pipe nests, in austral summer 2021 on Bird Island, South Africa. We also recorded penguin behaviour during the hottest period at each of these nest types using remote camera traps to determine the onset of heat stress (panting). Double-layered ceramic nests out-performed all other nest types, including natural burrows, by remaining cooler throughout the day, with temperatures never exceeding 36.7°C. By contrast, all other nest types had multiple episodes where temperatures exceeded 40°C. Double-layered ceramic nests also maintained constant levels of high humidity (relative humidity [RH] >70%) throughout our study, whereas low humidity levels were observed in surface nests (RH ≈ 60%) and cement nests (RH <50%) during midday heat. We observed penguins panting at temperatures of 25°C in nest boxes, and at 22°C in exposed surface nests. This suggests that heat stress in African Penguins may occur much sooner than anticipated and that they are particularly vulnerable to hyperthermia as climate change-related global warming progresses. Fortunately, we are encouraged by the capacity of double-layered ceramic nest boxes to buffer environmental extremes and maintain suitable breeding ... |
format |
Article in Journal/Newspaper |
author |
Welman, Shaun Pichegru, Lorien |
spellingShingle |
Welman, Shaun Pichegru, Lorien Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
author_facet |
Welman, Shaun Pichegru, Lorien |
author_sort |
Welman, Shaun |
title |
Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
title_short |
Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
title_full |
Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
title_fullStr |
Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
title_full_unstemmed |
Nest microclimate and heat stress in African Penguins Spheniscus demersus breeding on Bird Island, South Africa |
title_sort |
nest microclimate and heat stress in african penguins spheniscus demersus breeding on bird island, south africa |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/s0959270922000351 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0959270922000351 |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) ENVELOPE(163.650,163.650,-74.300,-74.300) ENVELOPE(141.604,141.604,-66.775,-66.775) |
geographic |
Austral Bird Island Burrows Guano |
geographic_facet |
Austral Bird Island Burrows Guano |
genre |
Bird Island |
genre_facet |
Bird Island |
op_source |
Bird Conservation International volume 33 ISSN 0959-2709 1474-0001 |
op_rights |
http://creativecommons.org/licenses/by/4.0 |
op_doi |
https://doi.org/10.1017/s0959270922000351 |
container_title |
Bird Conservation International |
container_start_page |
1 |
op_container_end_page |
9 |
_version_ |
1802642931505430528 |