IBA Hamilton Harbour Waterbird Colonies
Hamilton, Ontario
Site Summary
ON020 Latitude
43.287° N
79.804° W
75 - 78 m
14.23 km²
freshwater lake, unknown
Land Use:
Nature conservation and research, Urban/industrial/transport
Potential or ongoing Threats:
Disturbance, Interactions with native species/disease, Industrial pollution
IBA Criteria: Globally Significant: Colonial Waterbirds/Seabird Concentrations, Nationally Significant: Congregatory Species
Conservation status:
Restricted access for IBA coordinators
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Site Description
Hamilton Harbour is located at the extreme western end of Lake Ontario. It is separated from the Lake by a large sandbar (developed with highways, industries, and housing), with water exchange occurring through the Burlington Canal. The waterbird colonies are located at east end of the harbour, primarily in an area known as Eastport, as well as in the harbour's northeast corner.

Eastport is comprised of three partially developed piers (numbers 25, 26, and 27) that have been created over the past 35 years by the Hamilton Harbour Commission's filling operations. Eastern Cottonwood has become established on some of the piers, although in recent years it has died back (probably due to the acidic feces from nesting Double-crested Cormorants). In general, the piers at Eastport are flat with some elevated mounds (less than 2 m), and herbaceous vegetation such as celandines, mustards, and nettles.

Two small artificial islands (Farre and Neare Islands), which are comprised of coarse rocks and patches of sparse vegetation, are located in the northeast corner of the harbour. They were built in the 1920s and supported hydro poles until they were removed in 1983. Three additional nesting islands were constructed in this area during the winter of 1995-1996. They are located directly north of the Canadian Centre for Inland Waters and are called North, Central and South islands.

In terms of the IBA program, at least four species are present at this site in significant numbers: Ring-billed Gulls (almost 4.5% of the worlds estimated breeding population); Caspian Terns (about 1.25% of the estimated North American population, and as much as 7% of the estimated Great Lakes population); Common Terns (about 1.9% of the estimated North American population), and historically Black-crowned Night- Herons. The long-term population average for Black-crowned Night Herons (1987-1997) represents about 2% of Canada's estimated breeding population; in recent years, however, numbers (20 pairs in 1997) have been well below the national 1% threshold.

Other species of waterbirds nesting at these colonies include: Double-crested Cormorants (avg. of 422 pairs from 1987-97, with a peak of 819 pairs in 1996); and Herring Gulls (avg. of 290 pairs from 1987-1997, with a peak of 371 pairs in 1996). The only Canadian record of breeding Snowy Egret occurred here in 1986.

IBA Criteria
SpeciesT | A | I Links Date Season Number G C N
Caspian Tern 1997 SU 798
Greater Scaup 2009 FA 4,814
Greater Scaup 1993 - 2001 SP 5,000
Greater Scaup 2000 - 2010 WI 4,792 - 20,000
Little Gull 1992 SP 2
Little Gull 2014 SU 3
Loggerhead Shrike 1996 - 2012 SP 1
Long-tailed Duck 2009 WI 10,000
Ring-billed Gull 1995 SP 80,000
Ring-billed Gull 1990 SU 79,242
Note: species shown in bold indicate that the maximum number exceeds at least one of the IBA thresholds (sub-regional, regional or global). The site may still not qualify for that level of IBA if the maximum number reflects an exceptional or historical occurrence.
Conservation Issues
The management and monitoring of these colonies is being undertaken by the Canadian Wildlife Service, Brock University, and McMaster University. Local stakeholders, such as naturalists clubs, are also being encouraged to participate. Management efforts have focused primarily on enhancing nesting conditions for target species such as Black-crowned Night-Herons, Common Terns and Caspian Terns. The islands recently constructed in the northeast corner of the harbour were designed specifically to attract these species. On North Island, a 200m² elevated mound was constructed of sand and pea gravel to attract Caspian Terns. Areas of sand and gravel, each 250m², were placed on both North and Centre island to attract Common Terns. Two additional areas, one on Centre Island and all of South Island, were covered with topsoil and leaf mulch in preparation for planting of native shrubs to attract Black-crowned Night-Herons.

The IBA Program is an international conservation initiative coordinated by BirdLife International. The Canadian co-partners for the IBA Program are Birds Canada and Nature Canada.
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