Birds of Tommy Thompson Park

In 2000 Tommy Thompson Park / Leslie Street Spit was declared a Globally Significant Important Bird Area by BirdLife International. This designation was due to the globally significant numbers of nesting colonial waterbirds; the nationally significant numbers of waterfowl during migration and over winter; and the large concentrations of songbirds during migration.

TTP is an amazing spot to bird watch - 316 species of birds have been recorded at TTP, including at least 55 breeding species. The park is an important stopover during migration for many bird species that need to rest and refuel to continue their migration. In addition to many species of songbirds, migrations also include raptors, waterfowl and shorebirds.


The Tommy Thompson Park Bird Research Station is dedicated to the understanding and protection of birds and their habitats through monitoring, education and research.

DOWNLOAD: Tommy Thompson Park Bird Checklist, 2006

Habitat Enhancements for Birds

Habitat enhancements at TTP have targeted several bird species. Large scale projects, such as wetland creation, have targeted a range of species, birds included. Around the Cell One Wetland a bank was constructed to target nesting Bank Swallows and was an immediate success - just days after completion swallows were observed digging nests.


Small bird boxes throughout the site are used by Tree Swallows and hopefully in the future, Eastern Bluebirds. American Kestrel, Owl and waterfowl boxes for cavity nesters have also been installed in various locations throughout the park. Occasionally bird boxes benefit other wildlife, such as deer mice that have used boxes as nests. Duck platforms or tubes have been situated in strategic locations around the Cell One Wetland to encourage marsh nesting waterfowl.


Habitat brush piles throughout the park create micro-climates and are used by various bird species for nesting and foraging. Snags installed in various locations provide perching spots for raptors among other species; and they have also hosted nesting Northern Flickers.

flicker *by Ann Gray, TTP Volunteer Naturalist

One of the most successful projects was the Common Tern reef raft. Although the reef rafts are still in use in Cell Two and Embayment D, an island was created in Cell One to accommodate breeding terns. This was an outstanding success as terns colonized the island the very first year after completion. Caspian Tern mounds have been hit and miss at TTP. We have experienced record years of Caspian Tern productivity, as well as disappointments with no nesting success at all. We will continue to enhance Caspian Tern habitat and monitor Caspian Tern breeding attempts to help ensure the success of this species at TTP.

The most recent endeavor to target birds is the Shorebird Habitat Creation project. Shorebirds are subject to a large number of threats, including habitat loss. The Shorebird Habitat Creation project in the Toplands area will provide critical foraging and loafing habitat for migrating shorebirds and for resident shorebirds. Shallow ponds with open mudflats will have water depth managed to maximize the production and diversity of invertebrates. Water depth can also be altered to benefit other species, especially post-migration.

Future habitat enhancements that target birds may include nesting platforms for Black Terns; upland nesting opportunities for waterfowl; and encouragement of Trumpeter Swan nesting through control of the introduced Mute Swan.


Colonial Waterbirds of Tommy Thompson Park


The designation of TTP as a Globally Significant Important Bird Area by BirdLife International in 2000 was due in part to the globally and nationally significant numbers of birds that nest in large groups or colonies. There are 8 species of colonial birds that nest or have nested at TTP.

  • The Spit is home to one of the largest breeding Ring-billed Gull colonies in the world - at it's peak about 6% of the estimated global breeding population.
  • Herring Gulls are frequent nesters among the Ring-billed Gulls but have not nested in large numbers.
  • Great Black-backed Gulls have nested sporadically in the gull colony since 1982.
  • Black-crowned Night-Herons also nest at TTP with a long term average of approximately 17% of the estimated national breeding population. When their numbers peaked in 2000, the Night-Herons comprised about 32% of the estimated Canadian breeding population!
  • 11,990 pair of Double-crested Cormorants nested at TTP in 2013.
  • A recent addition to the colonial nesting birds are the Great Egrets that nest in with the Cormorant and Night-Heron colony.
  • Since 1976 Common Terns have nested in significant numbers on artificial breeding platforms or "reef rafts" and are now also nesting on an island designed as tern habitat in the Cell One as part of TRCA's wetland creation project. At the peak of Common Tern numbers the breeding population represented 1.8% of the estimated North American population.
  • Caspian Terns have nested at the Park in significant numbers with varying degrees of success. In 1985 the Caspian Tern population at TTP peaked and represented 1.3% of the estimated Canadian breeding population.

Ring-billed Gull (Larus delawarensis)

A common sight at beaches, parks and parking lots, the Ring-billed Gull is the most numerous species nesting at TTP. The current population is approximately 30,000 nesting pair. They nest in densely packed colonies on Peninsulas A and B, which have the large expanses of sparsely vegetated ground that they prefer, and make a scraped nest in the ground often ringed with dead vegetation. They also nest on the Endikement Tip, however this area is managed to prevent over-population.

Herring Gull (Larus argentatus)

Although larger and more aggressive than Ring-billed Gulls, Herring Gulls have a much smaller population at TTP. There are usually 60 to 80 Herring Gull nests near water on Peninsulas A and B, where they defend a nest made of dead vegetation and sticks in a large, sparsely vegetated territory. They are year-round residents of the Great Lakes and many Herring Gulls from northern regions come to overwinter in Toronto. Herring Gulls at TTP are a part of the long-term contaminants monitoring program started in 1974 by the Canadian Wildlife Service. The study collects eggs from around the Great Lakes and analyses them to determine the health of the lakes over time.

Great Black-backed Gull (Larus marinus)

Although the world's largest gull has not been recorded nesting at TTP recently, they are frequently seen at the park. They are essentially a predatory, marine bird and have been slowly increasing their Great Lakes breeding range. It is expected that the Great Black-backed Gull will nest again at TTP, although in very small numbers.

Black-crowned Night-Heron (Nycticorax nycticorax)

In 1979 the first Night-Herons nested on the Spit - about 7 pair. Since then, however, Night-Heron populations peaked to over 1200 nests, but their population has been gradually declining over the past several years, with 297 pair in 2013. The dense cottonwood areas on Peninsulas B and C provide nesting areas for the Night-Herons, where they are interspersed with Double-crested Cormorants and Great Egrets. Black-crowned Night-Herons, as their name implies, usually hunt at night and can be seen foraging in the shallows of the Embayments or Cell One.

Double-crested Cormorant (Phalocrocorax auritus)

Double-crested Cormorants began nesting at TTP in 1990 and have since become a common sight throughout Toronto Harbour. The TTP cormorant colony is the largest on the Great Lakes at 11,990 nesting pairs in 2013. Double-crested Cormorants are usually tree-nesters and prefer to be close to the water, which makes the Peninsulas ideal nesting locations. They have tree-nesting colonies on Peninsulas A, B and C and a ground nesting colony on Peninsula B which represents 50% of the population. They are often seen fishing and loafing in the Embayments, Triangle Pond, Cell One and offshore in Lake Ontario.

Great Egret (Ardea alba)

Several pair of Great Egrets nest at TTP, mixed in with the Black-crowned Night-Herons and Double-crested Cormorants on Peninsula C. The dense cottonwood stands are the perfect habitat for these high tree nesters. They can often be seen fishing in the shallow waters in Cell One and Triangle Pond, as well as along the shoreline in the Embayments, where they lunge quickly and stab fish with their long, pointed bill.

*by Ann Gray, TTP Volunteer Naaturalist

Common Tern (Sterna hirundo)

The Common Tern was the first colonial species to nest at TTP. Although populations appeared relatively stable, nest locations often shifted year to year likely due to habitat loss from natural succession; competition from gulls; and predation. To compensate for these variables TRCA, in partnership with the Canadian Wildlife Service, developed reef rafts. The rafts in Cell Two and Embayment D are very successful and have been complemented with permanent, natural habitat - a tern island in Cell One. All of these sites are used by nesting Common Terns. Watch for terns foraging over open water where they frequently dive for small fish.

Caspian Tern (Sterna caspia)

Caspian Terns have nested at TTP since 1976 with varying degrees of success. Their natural nesting preference is open sand and gravel beaches on islands where they have good visibility of the surrounding area. Caspian Terns are often seen foraging over water, particularly the Embayments and Cells Two and Three, where they dive dramatically into the water for fish.

Colonial Bird Monitoring

TRCA conducts annual counts of Double-crested Cormorants and Black-crowned Night-Herons to track changes in populations and nesting areas. Upon completion of nesting the forests are also monitored to measure any impacts the birds have upon the health of trees.

Ring-billed Gull management is an ongoing effort. Since the 1970s various management techniques have been employed for Ring-billed Gull population management. Some have estimated that if Ring-billed Gull management did not occur the population at TTP would be approximately 180, 000 pair of gulls!

Common Tern and Caspian Tern populations are also monitored by counting nests and noting any obvious areas of stress.

TRCA works in cooperation with the Canadian Wildlife Service (CWS) to count Ring-billed Gulls and Herring Gulls every five years. TRCA is also a partner with the CWS in long-term contaminant monitoring, as well as other colonial waterbird studies.

Research projects conducted by other organizations are ongoing at TTP. Colonial waterbirds are a popular theme - recent endeavours include dietary studies of Double-crested Cormorants and interaction between Double-crested Cormorants and Black-crowned Night-Herons.

Cormorants at Tommy Thompson Park

In 2007, Toronto and Region Conservation embarked on a process to investigate the need for cormorant management at TTP. TRCA established an advisory group of stakeholders and experts to review the status of the TTP cormorant colony and provide recommendations on possible management approaches. TRCA also consulted with the public at a meeting held in April 2008 and at the annual TTP Spring Bird Festival in May 2008. Background information and meeting notes can be found below.

A remote webcam was placed on the outskirt of the Peninsula B Double-crested Cormorant Ground Nest Colony for the duration of the 2012 breeding season.  The following is a 23 photo summary showing highlights from March to August. View the Tommy Thompson Park ground nest colony. 

The goal of management strategy is to achieve a balance between the continued existence of a healthy, thriving cormorant colony and the other ecological, educational, scientific and recreational values of Tommy Thompson Park. Management techniques being considered include: do nothing, deterrence, ground nest enhancements and site restoration. TRCA is not considering lethal culling, which has been used in other places around the Great Lakes.

With the large size of the ground nest colony, nest counts have been conducted by counting nests in aerial photos since 2014.  7,799 nests were counted in 2014 and 7,608 in 2015.  Below is one of the amazing pictures showing the ground nesting area.

2014 cormorant ground colony at TTP



TTP Backgrounder - 260K
Colonial Waterbird Glossary - 264K
Selected Annotated Reference Articles - 280K
TTP IBA document - 844K
Cormorant Management Workplan - 247K



Advisory Group Meeting Notes #14 - 58K
Advisory Group Meeting Notes #13 - 68K
Advisory Group Meeting Notes #12 - 64K
Advisory Group Meeting Notes #11 - 129K
Advisory Group Meeting Notes #10 - 132K
Advisory Group Meeting Notes #9 - 127K
Advisory Group Meeting Notes #8 - 189K
Advisory Group Meeting Notes #7 - 437K
Advisory Group Meeting Notes #6 - 452K
Advisory Group Meeting Notes #5 - 490K
Advisory Group Meeting Notes #4 - 437K
Advisory Group Meeting Notes #3 - 406K
Advisory Group Meeting Notes #2 - 306K
Advisory Group Meeting Notes #1 - 292K


TRCA Presentation for Public Meeting, April 3 2008 - 3,874K
Public Meeting Report, April 3 2008 - 942K


Authority Meeting Minutes January 2014 - 63K 
Authority Meeting Minutes January 2013 - 65 K
Authority Meeting Minutes March 2012 - 63 K
Authority Meeting Minutes March 2011 - 1,380 K
Authority Meeting Resolution #A23/10 Re: Double-crested Cormorant Management Strategy, 2010 -  1,394K
Authority Meeting Communication for Meeting #2/09 Re: Double-crested Cormorant Management Strategy, 2009 - 2,393K
Authority Meeting Recommendation #110/08 Re: Double-crested Cormorants Management Strategy, May 2008 - 1,818K

TTP Master Plan
Important Bird Areas of Canada
Bird Research Northwest: Columbia River Estuary Double-crested Cormorant Study




Tommy Thompson Park Natural Heritage



Reptiles and Amphibians


Vegetation Communities


Hours of Operation

Tommy Thompson Park is open to the public weekends and holidays, except Christmas Day, Boxing Day and New Year?s Day. Operating hours are 9 a.m. to 4:30 p.m. from November to March and 9 a.m. to 6 p.m. from March to November (coinciding with daylight savings time).



Tommy Thompson Park (TTP) is located at the base or foot of Leslie Street where it meets Unwin Avenue, south of Lake Shore Boulevard East.



Lake Ontario moderates TTP's climate, with less heat & humidity in the summer and less snow in the winter than areas immediately north. Prevailing winds are westerly, with faster speeds and greater wind chill effects. Fogs forms twice as often at TTP than the rest of Toronto.