Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada
Gulls (Larus spp.) are described as generalist, opportunistic feeders that show great flexibility in habitat use. Despite an apparent advantage in changing landscapes, many Larus populations have declined in eastern North America since the 1990s. The main hypothesis explaining gull declines at a bro...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Resilience Alliance
2021-06-01
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| Series: | Avian Conservation and Ecology |
| Subjects: | |
| Online Access: | https://www.ace-eco.org/vol16/iss1/art2/ |
| _version_ | 1797972802961145856 |
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| author | Katherine R. Shlepr Robert A. Ronconi Brian Hayden Karel A. Allard Antony W. Diamond |
| author_facet | Katherine R. Shlepr Robert A. Ronconi Brian Hayden Karel A. Allard Antony W. Diamond |
| author_sort | Katherine R. Shlepr |
| collection | DOAJ |
| description | Gulls (Larus spp.) are described as generalist, opportunistic feeders that show great flexibility in habitat use. Despite an apparent advantage in changing landscapes, many Larus populations have declined in eastern North America since the 1990s. The main hypothesis explaining gull declines at a broad scale is a decrease in total food availability, especially anthropogenically derived fisheries discards and human refuse as industries and cities have improved their management practices. However, it is difficult to quantify the total proportion of gull diet subsidized by humans to test this hypothesis because many common prey items can be traced to both anthropogenic and nonanthropogenic sources. Our aim was to estimate the proportion of diet derived from anthropogenic food sources for Herring Gull (L. argentatus) during the breeding season at the two largest colonies in the Bay of Fundy, Canada, which are located 36 km apart. GPS loggers were deployed to quantify spatiotemporal movement patterns, and whole blood and feather samples were collected for δ13C and δ15N stable-isotope analysis to estimate diet composition during the incubation and chick-rearing stages of the breeding season. Results indicate that there is spatial segregation in the foraging areas used by gulls from the two colonies. All gulls relied on a variety of anthropogenic food sources, with some individuals selecting heavily on fisheries (i.e., active town wharfs, fish packaging plants, aquaculture pens) and mink (Neovison vison) fur farms. Landfills were not a significant source of food during the breeding season. Our study provides valuable information about the relative reliance of gulls on anthropogenic food subsidies, providing insight into how changing industry practices may affect patterns in nesting and foraging by gulls in the region. |
| first_indexed | 2024-04-11T03:54:12Z |
| format | Article |
| id | doaj.art-799861e5152d4025b2442116dd461b09 |
| institution | Directory Open Access Journal |
| issn | 1712-6568 |
| language | English |
| last_indexed | 2024-04-11T03:54:12Z |
| publishDate | 2021-06-01 |
| publisher | Resilience Alliance |
| record_format | Article |
| series | Avian Conservation and Ecology |
| spelling | doaj.art-799861e5152d4025b2442116dd461b092023-01-02T01:04:30ZengResilience AllianceAvian Conservation and Ecology1712-65682021-06-0116121739Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, CanadaKatherine R. Shlepr0Robert A. Ronconi1Brian Hayden2Karel A. Allard3Antony W. Diamond4Atlantic Lab for Avian Research, University of New BrunswickCanadian Wildlife Service, Environment and Climate Change CanadaCanadian Rivers Institute, University of New BrunswickCanadian Wildlife Service, Environment and Climate Change CanadaAtlantic Lab for Avian Research, University of New BrunswickGulls (Larus spp.) are described as generalist, opportunistic feeders that show great flexibility in habitat use. Despite an apparent advantage in changing landscapes, many Larus populations have declined in eastern North America since the 1990s. The main hypothesis explaining gull declines at a broad scale is a decrease in total food availability, especially anthropogenically derived fisheries discards and human refuse as industries and cities have improved their management practices. However, it is difficult to quantify the total proportion of gull diet subsidized by humans to test this hypothesis because many common prey items can be traced to both anthropogenic and nonanthropogenic sources. Our aim was to estimate the proportion of diet derived from anthropogenic food sources for Herring Gull (L. argentatus) during the breeding season at the two largest colonies in the Bay of Fundy, Canada, which are located 36 km apart. GPS loggers were deployed to quantify spatiotemporal movement patterns, and whole blood and feather samples were collected for δ13C and δ15N stable-isotope analysis to estimate diet composition during the incubation and chick-rearing stages of the breeding season. Results indicate that there is spatial segregation in the foraging areas used by gulls from the two colonies. All gulls relied on a variety of anthropogenic food sources, with some individuals selecting heavily on fisheries (i.e., active town wharfs, fish packaging plants, aquaculture pens) and mink (Neovison vison) fur farms. Landfills were not a significant source of food during the breeding season. Our study provides valuable information about the relative reliance of gulls on anthropogenic food subsidies, providing insight into how changing industry practices may affect patterns in nesting and foraging by gulls in the region.https://www.ace-eco.org/vol16/iss1/art2/dietecosystem-based managementforaginggps trackinghabitat usenuisance speciespopulation declinestable-isotope analysisurban ecologywildlife management |
| spellingShingle | Katherine R. Shlepr Robert A. Ronconi Brian Hayden Karel A. Allard Antony W. Diamond Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada Avian Conservation and Ecology diet ecosystem-based management foraging gps tracking habitat use nuisance species population decline stable-isotope analysis urban ecology wildlife management |
| title | Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada |
| title_full | Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada |
| title_fullStr | Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada |
| title_full_unstemmed | Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada |
| title_short | Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada |
| title_sort | estimating the relative use of anthropogenic resources by herring gull larus argentatus in the bay of fundy canada |
| topic | diet ecosystem-based management foraging gps tracking habitat use nuisance species population decline stable-isotope analysis urban ecology wildlife management |
| url | https://www.ace-eco.org/vol16/iss1/art2/ |
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