American White Pelican Minnesota Conservation Summary

Transcription

1 Credit Carrol Henderson American White Pelican Minnesota Conservation Summary Audubon Minnesota Spring 2014 The Blueprint for Minnesota Bird Conservation is a project of Audubon Minnesota written by Lee A. Pfannmuller (leepfann@msn.com) and funded by the Environment and Natural Resources Trust Fund. For further information please contact Mark Martell at mmartell@audubon.org ( ).

2 American White Pelican Priority for Minnesota s Bird Conservation Plan: Prairie Parkland: Moderate Level Priority Potential Statewide Stewardship Species (23.6% of global population in Minnesota; 1/28% of North American breeding range: considered stewardship species based on high percentage of global population in Minnesota) Other Status Classifications: Officially classified as a Species of Special Concern in Minnesota Minnesota Species of Greatest Conservation Need (SGCN) Identified as a Species at Risk on Minnesota Audubon s Action List United States Waterbird Conservation Plan: Moderate Concern; apparently population decline (PT=4) Northern Prairie and Parkland Waterbird Region: Moderate Concern Upper Mississippi River and Great Lakes Waterbird Region: Moderate Priority in BCR12; To be Determined in BCR22; Moderate Priority in BCR23; Focal Species for Region-wide monitoring because it is a Stewardship Priority species in the UMVGL Region Population Information: North America population estimate: 67,030 breeding pairs ( ; King and Anderson 2005) Minnesota population estimate: 15,824 breeding pairs breeding at 16 different colony sites (Wires, Haws and Cuthbert 2005: The Double-crested Cormorant and American White Pelican in Minnesota: A Statewide Status Assessment) Minnesota has one of the largest North American colonies at Marsh Lake; over 80% of the state s population occurs in this location Minnesota BBS Data: Red Level of Credibility : Increasing trend (not statistically significant) of 20.0; : Increasing trend of 21.0 Minnesota Residency: Breeds mostly in the western half of Minnesota; migrant throughout. The bird did not nest in Minnesota after 1878 (Roberts 1932) but reappeared in 1968 when 70 nests were found at Marsh Lake. Since that time the species has expanded its population and distribution to approximately 16 nesting colonies and 15,824 breeding pairs. This recent increase is considered a recolonization of the species former range in the state (Minnesota DNR Rare Species Guide). Habitat Requirements: Lakes Unvegetated islands with associated open water; breeds mainly on isolated islands in freshwater lakes, forages on inland marshes, lakes, or rivers, favoring shallows (Birds of North America) Nests on barren islands in large lakes or more rarely rivers, often occurring in association with other colonial birds including Double-crested Cormorant, gulls and terns. During the breeding season forages in shallow waters of marshes, lakes and rivers. Some nesting and foraging areas are unstable due to changes in water levels, often resulting in considerable movement between sites. Winters mainly in shallow coastal waters; bays, inlets and estuaries; more rarely on inland waters (Northern Prairie & Parkland WCP). Migration: Temperate American White Pelican Page 2 of 5 Audubon Minnesota

3 Climate Change Vulnerability: Low (1) Threats/Issues (from NPP WCP): Perceived competition for fish resources with sport and commercial fisheries and resultant harassment of birds in some areas Periodic loss on nesting colonies of large numbers of individuals to disease/bacterial outbreaks such as Newcastle s disease, avian botulism, and West Nile Virus Water management may limit breeding opportunities or increase predator access High degree of concentration of breeding colonies; in Canadian portion of Northern Prairie and Parkland Region approximately 85% of breeders occur in five colonies West Nile Virus has been implicated in substantial die-offs of young American Whiter Pelicans at several nesting colonies in the United States OVERALL MINNESOTA GOAL: Insure protection of known colonies and annually monitor the Marsh Lake nesting complex BEST MANAGEMENT PRACTICES Protect known colony locations from human disturbance (colony desertion is common when pelicans are disturbed, particularly during courtship and incubation; MNDNR Rare Species Guide). Protect known colony locations from fluctuating water levels. MONITORING NEEDS Because the 4 nesting colonies located at Marsh Lake in west-central Minnesota comprise one of the largest nesting congregations of American White Pelicans in North America, its status should be monitored annually (Wires, Haws and Cuthbert 2005). Action: Conduct an annual aerial census of the Marsh Lake pelican nesting complex in mid-may (see Wire, Haws and Cuthbert 2005). The status of other significant pelican colonies (>100 pairs) in Minnesota also should be monitored regularly. This includes colonies in Lake of the Woods, Minnesota Lake, Red Lake and Pigeon Lake. Action: Per the recommendations of Wires, Haws and Cuthbert (2005), monitor the status of American White Pelican colonies that support at least 100 nesting pairs approximately every three years. Although aerial photography is recommended whenever possible because it is the least invasive method to census pelicans, ground counts can be conducted with minimal disturbance at these sites if gulls are not present, visits are short (< 1 hour), chicks are not ambulatory, nesting is well underway, and attention is paid to appropriate weather conditions. CONSERVATION ACTIONS Protect American White Pelican nesting sites that support significant concentrations of pelicans and a diversity of other colonial nesting species American White Pelican Page 3 of 5 Audubon Minnesota

4 Action: Provide special protection and/or designation to multi-species colonial nesting sites that support American White Pelicans. Background: Sites with diverse aggregations of nesting colonial waterbirds are relatively uncommon in Minnesota. In their 2005 report, Wires, Haws and Cuthbert identified several multi-species colonies that should be considered for special designations: Pigeon Lake, Lake Johanna, Leech Lake and Lake of the Woods (several islands within the lake). Double-crested cormorants occur at several of these sites. If cormorants are targeted for control efforts at these sites, the benefits of these activities must be carefully weighed against the impacts such activities will likely have on other colonial species and the unique natural resource these assemblages represent. In tree colonies, cormorants often nest in the same trees with herons and egrets, which are also highly sensitive to Perceived competition for fish resources with sport and commercial fisheries and resultant harassment of birds in some areas Periodic loss on nesting colonies of large numbers of individuals to disease/bacterial outbreaks such as Newcastle s disease, avian botulism and West Nile Virus RESEARCH NEEDS Investigate the perceived competition between pelicans and sport and commercial fisheries if the angling community begins to call for control of pelican populations as well as local cormorant populations. Action: Keep abreast of local control efforts for double-crested cormorants in Minnesota and be alert for calls of expanding the efforts to white pelicans. Should anglers request the initiation of pelican control efforts, work closely with federal and state resource agencies to ensure that peerreviewed research is initiated. Specific Actions for Audubon Chapters: Participate in monitoring nesting American White Pelicans at selected colonies. American White Pelican Page 4 of 5 Audubon Minnesota

5 MN DNR MN Breeding Bird Atlas Birds of North America American White Pelican Distribution Maps Birds of North America MNBBA 2014 American White Pelican American White Pelican Page 5 of 5 Audubon Minnesota