Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009
Canadian and U.S. federal wildlife agencies completed four decadal surveys, spanning the years 1977 to 2009, to census colonial waterbirds breeding on the Great Lakes and adjoining bodies of water. In this paper, we reports abundance, distribution, and general population trends of three species: Bla...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Resilience Alliance
2015-06-01
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| Series: | Avian Conservation and Ecology |
| Subjects: | |
| Online Access: | http://www.ace-eco.org/vol10/iss1/art7/ |
| _version_ | 1797970879426068480 |
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| author | Scott A. Rush Cynthia Pekarik D.V. Weseloh Francesca Cuthbert David Moore Linda Wires |
| author_facet | Scott A. Rush Cynthia Pekarik D.V. Weseloh Francesca Cuthbert David Moore Linda Wires |
| author_sort | Scott A. Rush |
| collection | DOAJ |
| description | Canadian and U.S. federal wildlife agencies completed four decadal surveys, spanning the years 1977 to 2009, to census colonial waterbirds breeding on the Great Lakes and adjoining bodies of water. In this paper, we reports abundance, distribution, and general population trends of three species: Black-crowned Night-Heron (Nycticorax nycticorax), Great Egret (Ardea alba), and Great Blue Heron (Ardea herodias). Estimates of nest numbers ranged from approximately 4000-6100 for the Black-crowned Night-Heron, 250-1900 for the Great Egret, and 3800-6400 for the Great Blue Heron. Average annual rates of change in nest numbers between the first (1977) and fourth (2008) census were â'1% for the Black-crowned Night-Heron, +23% for the Great Egret, and â'0.27% for the Great Blue Heron. Across the 30-year census, Black-crowned Night-Heron estimates decreased in U.S. (â'57%) but increased (+18%) in Canadian waters, Great Egret nests increased 1381% in Canadian waters with a smaller, but still substantial increase in the number of nests at U.S. colonies (+613%), and Great Blue Heron numbers increased 148% in Canadian waters and 713% in U.S. waters. Although a single factor cannot be clearly linked to changes observed in each species' distribution, hydrological variation, habitat succession, nest competition with Double-crested Cormorants (Phalacrocorax auritus), and land use changes likely all contributed. Management activities should support both breeding and foraging conditions including restoration of early successional habitats and anticipate continued northward expansions in the distributions of these waterbirds. |
| first_indexed | 2024-04-11T03:23:58Z |
| format | Article |
| id | doaj.art-b8425b02dc184bdcae0743a3b3bf291a |
| institution | Directory Open Access Journal |
| issn | 1712-6568 |
| language | English |
| last_indexed | 2024-04-11T03:23:58Z |
| publishDate | 2015-06-01 |
| publisher | Resilience Alliance |
| record_format | Article |
| series | Avian Conservation and Ecology |
| spelling | doaj.art-b8425b02dc184bdcae0743a3b3bf291a2023-01-02T08:13:55ZengResilience AllianceAvian Conservation and Ecology1712-65682015-06-01101710.5751/ACE-00742-100107742Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009Scott A. Rush0Cynthia Pekarik1D.V. Weseloh2Francesca Cuthbert3David Moore4Linda Wires5Mississippi State UniversityCanadian Wildlife ServiceCanadian Wildlife ServiceDepartment of Fisheries, Wildlife and Conservation Biology, University of MinnesotaCanadian Wildlife ServiceDepartment of Fisheries, Wildlife and Conservation Biology, University of MinnesotaCanadian and U.S. federal wildlife agencies completed four decadal surveys, spanning the years 1977 to 2009, to census colonial waterbirds breeding on the Great Lakes and adjoining bodies of water. In this paper, we reports abundance, distribution, and general population trends of three species: Black-crowned Night-Heron (Nycticorax nycticorax), Great Egret (Ardea alba), and Great Blue Heron (Ardea herodias). Estimates of nest numbers ranged from approximately 4000-6100 for the Black-crowned Night-Heron, 250-1900 for the Great Egret, and 3800-6400 for the Great Blue Heron. Average annual rates of change in nest numbers between the first (1977) and fourth (2008) census were â'1% for the Black-crowned Night-Heron, +23% for the Great Egret, and â'0.27% for the Great Blue Heron. Across the 30-year census, Black-crowned Night-Heron estimates decreased in U.S. (â'57%) but increased (+18%) in Canadian waters, Great Egret nests increased 1381% in Canadian waters with a smaller, but still substantial increase in the number of nests at U.S. colonies (+613%), and Great Blue Heron numbers increased 148% in Canadian waters and 713% in U.S. waters. Although a single factor cannot be clearly linked to changes observed in each species' distribution, hydrological variation, habitat succession, nest competition with Double-crested Cormorants (Phalacrocorax auritus), and land use changes likely all contributed. Management activities should support both breeding and foraging conditions including restoration of early successional habitats and anticipate continued northward expansions in the distributions of these waterbirds.http://www.ace-eco.org/vol10/iss1/art7/Black-crowned Night-HeronGreat Blue HeronGreat Egrethabitat successionislandspopulation trends |
| spellingShingle | Scott A. Rush Cynthia Pekarik D.V. Weseloh Francesca Cuthbert David Moore Linda Wires Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 Avian Conservation and Ecology Black-crowned Night-Heron Great Blue Heron Great Egret habitat succession islands population trends |
| title | Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 |
| title_full | Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 |
| title_fullStr | Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 |
| title_full_unstemmed | Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 |
| title_short | Changes in heron and egret populations on the Laurentian Great Lakes and connecting channels, 1977-2009 |
| title_sort | changes in heron and egret populations on the laurentian great lakes and connecting channels 1977 2009 |
| topic | Black-crowned Night-Heron Great Blue Heron Great Egret habitat succession islands population trends |
| url | http://www.ace-eco.org/vol10/iss1/art7/ |
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