Ring-billed Gull

Larus delawarensis

General Status Rank: 
Secure
Common Name: 
Ring-billed Gull
Scientific Name: 
Larus delawarensis
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Taxonomy
Group: 
Bird
Kingdom: 
Animalia
Phylum: 
Chordata
Class: 
Aves
Order: 
Charadriiformes
Family: 
Laridae
Habitat
Nests on ground in close proximity to water mostly on low elevation (2–30 m) islands with a variety of sparse or woody vegetation; occasionally on peninsulas in large freshwater lakes; rarely on islands in rivers.
References: 
H126-05
B156
Distribution

Ecozones

Taiga Plains, Boreal Plains
References: 
B156

Distribution

about 10%, south of Great Slave Lake and just north of it, expended; Range extent estimated from map provided in CWS, 2009 (Canadian Wildlife Service - Prairie and Northern Region, 2009. Bird Distributions in Nunavut and the Northwest Territories: 2009 Review).
Score: 
FG
References: 
MAF4
B156

Area of Occupancy

Recently expanded north to Great Slave Lake, NWT (Sirois et al. 1991);
Score: 
-
References: 
B156
Population

Population Size

Exact population in the NWT not known. Approximately 600 nesting adults present on Great Slave Lake (R257, but numbers not known for other areas of the territory.
Score: 
CD
References: 
R257
Trends

Trends

Range continues to expand with most recent new western colonies in Northwest Territories and central and w. British Columbia. Northern expansion may result from climatic warming which would serve to enhance the productivity of Great Slave Lake and favor increase in local gull numbers (Sirois et al. 1991).Apparently increasing in some parts of the territory, as evidenced by presence of newly formed breeding colonies, but degree of increase has not been quantified.
Score: 
H
References: 
B156
Threats

Threats

Sensitive to disturbance at nesting colonies.
Score: 
C
References: 
H126-05

Intrinsic Vulnerability

limited
Score: 
-
References: 
H126-05
General Status Rank
Rank: 
Secure
Status Rank Description: 
In the NWT, at northern extent of North American range. Range expanded north to Great Slave Lake in the 1980's, and range expansion has continued since (BNA account, Canadian Wildlife Service - Prairie and Northern Region, 2009. Bird Distributions in Nunavut and the Northwest Territories: 2009 Review). Population apparently stable or increasing, with no evidence of significant threats or population declines.
S Rank: 
S4
Decision Process Description: 
Drafted in 2005 by S Carriere based on printed infromation only, was missing from the 2000 list by error.
Last Updated: 
July 10, 2015

References

Area of Occupancy

  • Ryder, J. P. (1993) Ring-billed Gull. In The Birds of North America, American Ornithologists’ Union.. No. 33 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The - B156 Return

Ecozones

  • Ryder, J. P. (1993) Ring-billed Gull. In The Birds of North America, American Ornithologists’ Union.. No. 33 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The - B156 Return

Habitat

  • Suzanne Carriere (2005) Pers. Comm.. - H126-05 Return
  • Ryder, J. P. (1993) Ring-billed Gull. In The Birds of North America, American Ornithologists’ Union.. No. 33 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The - B156 Return

Intrinsic Vulnerability

  • Suzanne Carriere (2005) Pers. Comm.. - H126-05 Return

Population Size

Woodard, P.F., M.A. Fournier, and M.O. Wiebe Robertson. (2013) Technical Report Series No. 526, Canadian Wildlife Service, Yellowknife, NT.). http://ec.gc.ca/nature/8A501AF4-58FB-4EDD-85BC-6A8221031199/North_Arm_Larid_Report_E_v3_web.pdf - R257 Return

Range Extent

  • Sirois, J., M.A. Fournier, and M. Kay (1995) The colonial waterbirds of Great Slave Lake, Northwest Territories: an annotated atlas. Canadian Wildlife Service Occasional Paper No. 89 - MAF4 Return
  • Ryder, J. P. (1993) Ring-billed Gull. In The Birds of North America, American Ornithologists’ Union.. No. 33 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The - B156 Return

Short Term Trends

  • Ryder, J. P. (1993) Ring-billed Gull. In The Birds of North America, American Ornithologists’ Union.. No. 33 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The - B156 Return

Threats

  • Suzanne Carriere (2005) Pers. Comm.. - H126-05 Return