Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands
Abstract Background Animals need adaptive strategies to cope with seasonal changes in prey availability to survive and reproduce, which can include migrating, prey-switching, or reducing metabolic needs. Human settlements can disrupt spatiotemporal patterning in resource availability, which can affe...
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Springer Science and Business Media LLC
2020
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Online Access: | http://dx.doi.org/10.1186/s40317-020-00214-y https://link.springer.com/content/pdf/10.1186/s40317-020-00214-y.pdf https://link.springer.com/article/10.1186/s40317-020-00214-y/fulltext.html |
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crspringernat:10.1186/s40317-020-00214-y 2023-05-15T18:15:06+02:00 Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands Harrington, Katie J. Fahlbusch, James A. Langrock, Roland Therrien, Jean-François Houtz, Jennifer L. McDonald, Birgitte I. 2020 http://dx.doi.org/10.1186/s40317-020-00214-y https://link.springer.com/content/pdf/10.1186/s40317-020-00214-y.pdf https://link.springer.com/article/10.1186/s40317-020-00214-y/fulltext.html en eng Springer Science and Business Media LLC https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 CC-BY Animal Biotelemetry volume 8, issue 1 ISSN 2050-3385 Computer Networks and Communications Instrumentation Animal Science and Zoology Signal Processing journal-article 2020 crspringernat https://doi.org/10.1186/s40317-020-00214-y 2022-01-04T09:20:17Z Abstract Background Animals need adaptive strategies to cope with seasonal changes in prey availability to survive and reproduce, which can include migrating, prey-switching, or reducing metabolic needs. Human settlements can disrupt spatiotemporal patterning in resource availability, which can affect animals’ foraging success, particularly for juveniles who are behaviorally developing and learning efficient foraging skills. Here, we investigate behavioral responses of juvenile striated caracaras, a near-threatened scavenging falconid, to seasonally migratory seabird prey and a farm settlement on Saunders Island, Falklands. We deployed accelerometer–GPS dataloggers ( n = 27) to measure seasonal differences in daily and hourly vectorial dynamic body acceleration (VeDBA; an activity index measured in gravitational g) and space use, and investigated seasonal variation in body mass of the tagged subset and an additional 65 caracaras. Results Juvenile caracaras were overall similarly active in winter and summer. However, during winter, caracaras made the most of limited daylight by increasing average daytime activity (winter males: 0.16 ± 0.03 g, summer males: 0.09 ± 0.01 g, winter females: 0.12 ± 0.02 g, summer females: 0.08 ± 0.01 g). During winter, both sexes increased the percentage of daylight spent in high activity (winter males: 35 ± 5%, summer males: 21 ± 3%, winter females: 25 ± 6%, summer females: 16 ± 3%, p < 0.001) and ranged nearly 4 times farther (95% kernel density estimate winter: 2.36 ± 0.96 km 2 , summer: 0.61 ± 0.20 km 2 p < 0.001). Furthermore, on a daily scale, males were 21% more active than females year-round (24-h average VeDBA: males 0.07 ± 0.01 g, females 0.06 ± 0.01 g; p < 0.01). We did not observe a significant seasonal difference in mass. Conclusion That caracaras’ daily activity and body mass did not vary between seasons suggests that wintering birds on Saunders are meeting resource requirements despite the absence of seasonally migratory prey. We hypothesize that human subsidies may mitigate the effect of seasonal food limitations. Further research should include studies on seasonal energetics to improve our understanding of baseline body condition, and comparative studies on other islands and including adults to understand the importance of human subsidies. Article in Journal/Newspaper Saunders Island Springer Nature (via Crossref) Saunders ENVELOPE(-45.316,-45.316,-60.700,-60.700) Saunders Island ENVELOPE(-26.450,-26.450,-57.783,-57.783) Animal Biotelemetry 8 1 |
institution |
Open Polar |
collection |
Springer Nature (via Crossref) |
op_collection_id |
crspringernat |
language |
English |
topic |
Computer Networks and Communications Instrumentation Animal Science and Zoology Signal Processing |
spellingShingle |
Computer Networks and Communications Instrumentation Animal Science and Zoology Signal Processing Harrington, Katie J. Fahlbusch, James A. Langrock, Roland Therrien, Jean-François Houtz, Jennifer L. McDonald, Birgitte I. Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
topic_facet |
Computer Networks and Communications Instrumentation Animal Science and Zoology Signal Processing |
description |
Abstract Background Animals need adaptive strategies to cope with seasonal changes in prey availability to survive and reproduce, which can include migrating, prey-switching, or reducing metabolic needs. Human settlements can disrupt spatiotemporal patterning in resource availability, which can affect animals’ foraging success, particularly for juveniles who are behaviorally developing and learning efficient foraging skills. Here, we investigate behavioral responses of juvenile striated caracaras, a near-threatened scavenging falconid, to seasonally migratory seabird prey and a farm settlement on Saunders Island, Falklands. We deployed accelerometer–GPS dataloggers ( n = 27) to measure seasonal differences in daily and hourly vectorial dynamic body acceleration (VeDBA; an activity index measured in gravitational g) and space use, and investigated seasonal variation in body mass of the tagged subset and an additional 65 caracaras. Results Juvenile caracaras were overall similarly active in winter and summer. However, during winter, caracaras made the most of limited daylight by increasing average daytime activity (winter males: 0.16 ± 0.03 g, summer males: 0.09 ± 0.01 g, winter females: 0.12 ± 0.02 g, summer females: 0.08 ± 0.01 g). During winter, both sexes increased the percentage of daylight spent in high activity (winter males: 35 ± 5%, summer males: 21 ± 3%, winter females: 25 ± 6%, summer females: 16 ± 3%, p < 0.001) and ranged nearly 4 times farther (95% kernel density estimate winter: 2.36 ± 0.96 km 2 , summer: 0.61 ± 0.20 km 2 p < 0.001). Furthermore, on a daily scale, males were 21% more active than females year-round (24-h average VeDBA: males 0.07 ± 0.01 g, females 0.06 ± 0.01 g; p < 0.01). We did not observe a significant seasonal difference in mass. Conclusion That caracaras’ daily activity and body mass did not vary between seasons suggests that wintering birds on Saunders are meeting resource requirements despite the absence of seasonally migratory prey. We hypothesize that human subsidies may mitigate the effect of seasonal food limitations. Further research should include studies on seasonal energetics to improve our understanding of baseline body condition, and comparative studies on other islands and including adults to understand the importance of human subsidies. |
format |
Article in Journal/Newspaper |
author |
Harrington, Katie J. Fahlbusch, James A. Langrock, Roland Therrien, Jean-François Houtz, Jennifer L. McDonald, Birgitte I. |
author_facet |
Harrington, Katie J. Fahlbusch, James A. Langrock, Roland Therrien, Jean-François Houtz, Jennifer L. McDonald, Birgitte I. |
author_sort |
Harrington, Katie J. |
title |
Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
title_short |
Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
title_full |
Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
title_fullStr |
Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
title_full_unstemmed |
Seasonal activity levels of a farm-island population of striated caracaras (Phalcoboenus australis) in the Falkland Islands |
title_sort |
seasonal activity levels of a farm-island population of striated caracaras (phalcoboenus australis) in the falkland islands |
publisher |
Springer Science and Business Media LLC |
publishDate |
2020 |
url |
http://dx.doi.org/10.1186/s40317-020-00214-y https://link.springer.com/content/pdf/10.1186/s40317-020-00214-y.pdf https://link.springer.com/article/10.1186/s40317-020-00214-y/fulltext.html |
long_lat |
ENVELOPE(-45.316,-45.316,-60.700,-60.700) ENVELOPE(-26.450,-26.450,-57.783,-57.783) |
geographic |
Saunders Saunders Island |
geographic_facet |
Saunders Saunders Island |
genre |
Saunders Island |
genre_facet |
Saunders Island |
op_source |
Animal Biotelemetry volume 8, issue 1 ISSN 2050-3385 |
op_rights |
https://creativecommons.org/licenses/by/4.0 https://creativecommons.org/licenses/by/4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1186/s40317-020-00214-y |
container_title |
Animal Biotelemetry |
container_volume |
8 |
container_issue |
1 |
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