Ontario Shorebird Survey

Photo of Lesser Yellowlegs
Photo: © Christian Friis, 2015
Lesser Yellowlegs

The Ontario Shorebird Survey (OSS) was developed by Environment and Climate Change Canada's Canadian Wildlife Service in 1974 to better understand the timing and size of the shorebird migration and to identify important areas used by these birds during spring and fall migration. More recently, the data collected by the survey has been used to estimate trends in shorebird populations. Volunteers are vital to the ongoing implementation of the OSS.

The OSS is the only inland shorebird survey in Canada and is part of a network of regional surveys, including the Atlantic Canada Shorebird Survey and the International Shorebird Survey, all of which share a common goal: to use the best available knowledge in order to conserve shorebird populations.

In much of North America, shorebird surveys are designed so that observers choose pre-determined local sites that are easily accessible, and monitor these areas during shorebird migration. In more remote northern areas, aerial surveys are conducted and temporary remote camps are established to monitor shorebirds during southbound migration. OSS sites are primarily situated in southern Ontario (Figure 1).

In the early days of the program, the survey consisted of a coordinated series of counts carried out at a small number of sites, but since then over 110 observers have collected data from more than 250 sites across Ontario. Today, regular data collection at about 20 OSS sites is coordinated by Environment and Climate Change Canada's Canadian Wildlife Service as a volunteer-based survey that continues to rely on the skills, dedication and long-term support of birders throughout Ontario.

Based on the analysis of shorebird migration data (1974-2009) representing over 40 shorebird species (Table 1), it is estimated that of the 19 taxa for which trends were generated, 17 are experiencing declining population trends (Ross et al. 2012; Status of Birds in Canada). Several of these shorebird species have been assessed by COSEWIC and are listed under the Species at Risk Act.

Photo of Volunteers observing migrating shorebirds
Photo : © Ron Ridout, 2015
Volunteers counting migrant shorebirds

OSS volunteers enjoy bird watching but also understand the importance of following a survey protocol to collect information that can be used to help better understand and conserve birds. Skill levels vary and new observers are provided with tools and support to help identify and census shorebird species.

Traditional OSS sites are portions of beaches, freshwater marshes, sewage lagoons, or fields. In an effort to expand the scope of the survey, new sites can be selected by observers with the help of the OSS coordinator. Together these sites will provide us with the data we need to assess population trends and habitat use of shorebirds that migrate through Ontario.

Figure 1. Map of Ontario Shorebird Survey sites
Map of Ontario Shorebird Survey sites
Long description for Figure 1

In more remote northern areas, aerial surveys are conducted and temporary remote camps are established to monitor shorebirds during southbound migration. OSS sites are primarily situated in southern Ontario.

Pectoral Sandpipers
Photo: © Mark Peck, 2015
Pectoral Sandpipers

OSS sites are surveyed annually between April 20 - June 10 and July 20 - November 1. During these periods, volunteers visit their site once every 10 days to identify and count all shorebirds observed. In general, the more counts undertaken at a site, and the longer the record of years, the more valuable these data become for shorebird population assessments and guiding conservation efforts.

At the end of the field season, OSS data are sent to the OSS coordinator or uploaded via an online data entry portal. The OSS database can be accessed by Environment and Climate Change Canada, provincial governments, academics, students, NGOs and other interested groups for use in research and conservation.

If you are interested in contributing to the Ontario Shorebird Survey or would like more information, please contact us (see contact information below).

Follow the link for the data sheets, guidelines and information you need to get started, or contact us and we can provide these to you.

Join the Ontario Shorebird Survey!

To contact us you can...

  • Send an email to the Shorebird Survey coordinator at:
  • Send regular mail to:
    Shorebird Biologist
    Canadian Wildlife Service
    Environment and Climate Change Canada
    4905 Dufferin St.
    Toronto ON M3H 5T4
  • Or give us a call at
Table 1: Shorebird species recorded in southern Ontario during spring and fall migration (Bird Conservation Regions 13 and 12).
English name French name Scientific name Status
Northern Lapwing Vanneau huppé Vanellus vanellus Rare/Accidental
Black-bellied Plover Pluvier argenté Pluvialis squatarola Common Migrant
American Golden-Plover Pluvier bronzé Pluvialis dominica Migrant
Snowy Plover Pluvier neigeux Charadrius nivosus Rare/Accidental
Semipalmated Plover Pluvier semipalmé Charadrius semipalmatus Common Migrant
Piping Plover Pluvier siffleur Charadrius melodus Uncommon Migrant, Rare Breeder
Killdeer Pluvier kildir Charadrius vociferus Breeder, Common Migrant
Mountain Plover Pluvier montagnard Charadrius montanus Rare/Accidental
American Oystercatcher Huîtrier d'Amérique Haematopus palliatus Rare/Accidental
Black-necked Stilt Échasse d'Amérique Himantopus mexicanus Rare/Accidental
American Avocet Avocette d'Amérique Recurvirostra americana Rare/Accidental
Spotted Sandpiper Chevalier grivelé Actitis macularius Breeder, Common Migrant
Solitary Sandpiper Chevalier solitaire Tringa solitaria Migrant
Greater Yellowlegs Grand Chevalier Tringa melanoleuca Common Migrant
Willet Chevalier semipalmé Tringa semipalmata Uncommon Migrant
Lesser Yellowlegs Petit Chevalier Tringa flavipes Common Migrant
Upland Sandpiper Maubèche des champs Bartramia longicauda Breeder, Uncommon Migrant
Whimbrel Courlis corlieu Numenius phaeopus Common Migrant
Hudsonian Godwit Barge hudsonienne Limosa haemastica Uncommon Migrant
Marbled Godwit Barge marbrée Limosa fedoa Uncommon Migrant
Ruddy Turnstone Tournepierre à collier Arenaria interpres Common Migrant
Red Knot Bécasseau maubèche Calidris canutus Migrant
Sanderling Bécasseau sanderling Calidris alba Common Migrant
Semipalmated Sandpiper Bécasseau semipalmé Calidris pusilla Common Migrant
Western sandpiper Bécasseau d'Alaska Calidris mauri Rare/Accidental
Least Sandpiper Bécasseau minuscule Calidris minutilla Common Migrant
White-rumped Sandpiper Bécasseau à croupion blanc Calidris fuscicollis Migrant
Baird's Sandpiper Bécasseau de Baird Calidris bairdii Migrant
Pectoral Sandpiper Bécasseau à poitrine cendrée Calidris melanotos Migrant
Purple Sandpiper Bécasseau violet Calidris maritima Uncommon Migrant, Overwinters
Dunlin Bécasseau variable Calidris alpina Common Migrant
Curlew Sandpiper Bécasseau cocorli Calidris ferruginea Rare/Accidental
Stilt Sandpiper Bécasseau à échasses Calidris himantopus Migrant
Buff-breasted Sandpiper Bécasseau roussâtre Tryngites subruficollis Uncommon Migrant
Ruff Combattant varié Philomachus pugnax Rare/Accidental
Short-billed Dowitcher Bécassin roux Limnodromus griseus Migrant
Long-billed dowitcher Bécassin à long bec Limnodromus scolopaceus Uncommon Migrant
Wilson's Snipe Bécassine de Wilson Gallinago delicata Breeder, Migrant
American Woodcock Bécasse d'Amérique Scolopax minor Breeder, Migrant
Wilson's Phalarope Phalarope de Wilson Phalaropus tricolor Migrant
Red-necked Phalarope Phalarope à bec étroit Phalaropus lobatus Uncommon Migrant
Red Phalarope Phalarope à bec large Phalaropus fulicarius Uncommon Migrant
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