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...

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Autores principales:	Katherine R. Shlepr, Robert A. Ronconi, Brian Hayden, Karel A. Allard, Antony W. Diamond
Formato:	article
Lenguaje:	EN
Publicado:	Resilience Alliance 2021
Materias:	diet ecosystem-based management foraging gps tracking habitat use nuisance species population decline stable-isotope analysis urban ecology wildlife management Plant culture SB1-1110 Environmental sciences GE1-350 Plant ecology QK900-989
Acceso en línea:	https://doaj.org/article/799861e5152d4025b2442116dd461b09
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spelling	oai:doaj.org-article:799861e5152d4025b2442116dd461b092021-11-15T16:40:14ZEstimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada1712-6568https://doaj.org/article/799861e5152d4025b2442116dd461b092021-06-01T00:00:00Zhttps://www.ace-eco.org/vol16/iss1/art2/https://doaj.org/toc/1712-6568Gulls (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.Katherine R. ShleprRobert A. RonconiBrian HaydenKarel A. AllardAntony W. DiamondResilience Alliancearticledietecosystem-based managementforaginggps trackinghabitat usenuisance speciespopulation declinestable-isotope analysisurban ecologywildlife managementPlant cultureSB1-1110Environmental sciencesGE1-350Plant ecologyQK900-989ENAvian Conservation and Ecology, Vol 16, Iss 1, p 2 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	diet ecosystem-based management foraging gps tracking habitat use nuisance species population decline stable-isotope analysis urban ecology wildlife management Plant culture SB1-1110 Environmental sciences GE1-350 Plant ecology QK900-989
spellingShingle	diet ecosystem-based management foraging gps tracking habitat use nuisance species population decline stable-isotope analysis urban ecology wildlife management Plant culture SB1-1110 Environmental sciences GE1-350 Plant ecology QK900-989 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
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.
format	article
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
title	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_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_sort	estimating the relative use of anthropogenic resources by herring gull (larus argentatus) in the bay of fundy, canada
publisher	Resilience Alliance
publishDate	2021
url	https://doaj.org/article/799861e5152d4025b2442116dd461b09
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Estimating the relative use of anthropogenic resources by Herring Gull (Larus argentatus) in the Bay of Fundy, Canada

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