Population dynamics, foraging ecology, and management of gulls on Monomoy NWR

Increases in numbers of Herring (L. argentatus) and Great Black-backed (L. marinus) gulls, and concurrent decreases in numbers of other beach-nesting birds, led to the proposed use of avicides to control gulls on Monomoy NWR, Chatham, Massachusetts. The purpose of this study was to obtain biological...

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Main Author: Cavanagh, Paul M
Format: Text
Language:English
Published: ScholarWorks@UMass Amherst 1992
Subjects:
Online Access:https://scholarworks.umass.edu/dissertations/AAI9219416
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spelling ftunivmassamh:oai:scholarworks.umass.edu:dissertations-8358 2023-12-17T10:28:56+01:00 Population dynamics, foraging ecology, and management of gulls on Monomoy NWR Cavanagh, Paul M 1992-01-01T08:00:00Z https://scholarworks.umass.edu/dissertations/AAI9219416 ENG eng ScholarWorks@UMass Amherst https://scholarworks.umass.edu/dissertations/AAI9219416 Doctoral Dissertations Available from Proquest Forestry|Ecology|Zoology text 1992 ftunivmassamh 2023-11-23T19:09:49Z Increases in numbers of Herring (L. argentatus) and Great Black-backed (L. marinus) gulls, and concurrent decreases in numbers of other beach-nesting birds, led to the proposed use of avicides to control gulls on Monomoy NWR, Chatham, Massachusetts. The purpose of this study was to obtain biological information on Monomoy's gull populations, and to use this information to develop and evaluate gull control strategies. Landfill use differed between species. Herring Gulls used more, and traveled farther to, landfills than did Great Black-backed Gulls. Herring Gulls used fewer landfills during the non-breeding than breeding season. Numbers of Herring Gulls in landfills were significantly related to human populations served by those landfills (r$\sp2$ = 0.63, P = 0.0003), Great Black-backed Gull numbers were not. Although both species consumed refuse and natural foods, more Herring than Great Black-backed gull stomachs contained refuse $(X\sp2$ = 7.88, P $<$ 0.005 in 1988; $X\sp2$ = 13.93, P $<$ 0.0002 in 1989). Refuse was a minor dietary component for both species' chicks. The passage of large gulls over nest sites had little impact on Monomoy's Common Tern (Sterna hirundo) and Laughing Gull (L. atricilla) colonies. Few fly-overs (49, 0.04%) at altitudes of 20 m or less resulted in mobbings or disturbances. Terns mobbed large gulls more often than did Laughing Gulls (G = 16.61, P $<$ 0.005), but numbers of birds per mobbing did not differ between species (t = 0.95, P $>$ 0.05). Both species habituated to fly-overs and ignored most large gulls. We developed a deterministic simulation model to identify the effects of different types and levels of control on gull population dynamics. Effectiveness of gull control varied with technique, but no method completely eliminated Herring or Great Black-backed gulls. Model construction and interpretation of outputs are described. Text Common tern Sterna hirundo University of Massachusetts: ScholarWorks@UMass Amherst
institution Open Polar
collection University of Massachusetts: ScholarWorks@UMass Amherst
op_collection_id ftunivmassamh
language English
topic Forestry|Ecology|Zoology
spellingShingle Forestry|Ecology|Zoology
Cavanagh, Paul M
Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
topic_facet Forestry|Ecology|Zoology
description Increases in numbers of Herring (L. argentatus) and Great Black-backed (L. marinus) gulls, and concurrent decreases in numbers of other beach-nesting birds, led to the proposed use of avicides to control gulls on Monomoy NWR, Chatham, Massachusetts. The purpose of this study was to obtain biological information on Monomoy's gull populations, and to use this information to develop and evaluate gull control strategies. Landfill use differed between species. Herring Gulls used more, and traveled farther to, landfills than did Great Black-backed Gulls. Herring Gulls used fewer landfills during the non-breeding than breeding season. Numbers of Herring Gulls in landfills were significantly related to human populations served by those landfills (r$\sp2$ = 0.63, P = 0.0003), Great Black-backed Gull numbers were not. Although both species consumed refuse and natural foods, more Herring than Great Black-backed gull stomachs contained refuse $(X\sp2$ = 7.88, P $<$ 0.005 in 1988; $X\sp2$ = 13.93, P $<$ 0.0002 in 1989). Refuse was a minor dietary component for both species' chicks. The passage of large gulls over nest sites had little impact on Monomoy's Common Tern (Sterna hirundo) and Laughing Gull (L. atricilla) colonies. Few fly-overs (49, 0.04%) at altitudes of 20 m or less resulted in mobbings or disturbances. Terns mobbed large gulls more often than did Laughing Gulls (G = 16.61, P $<$ 0.005), but numbers of birds per mobbing did not differ between species (t = 0.95, P $>$ 0.05). Both species habituated to fly-overs and ignored most large gulls. We developed a deterministic simulation model to identify the effects of different types and levels of control on gull population dynamics. Effectiveness of gull control varied with technique, but no method completely eliminated Herring or Great Black-backed gulls. Model construction and interpretation of outputs are described.
format Text
author Cavanagh, Paul M
author_facet Cavanagh, Paul M
author_sort Cavanagh, Paul M
title Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
title_short Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
title_full Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
title_fullStr Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
title_full_unstemmed Population dynamics, foraging ecology, and management of gulls on Monomoy NWR
title_sort population dynamics, foraging ecology, and management of gulls on monomoy nwr
publisher ScholarWorks@UMass Amherst
publishDate 1992
url https://scholarworks.umass.edu/dissertations/AAI9219416
genre Common tern
Sterna hirundo
genre_facet Common tern
Sterna hirundo
op_source Doctoral Dissertations Available from Proquest
op_relation https://scholarworks.umass.edu/dissertations/AAI9219416
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