» Ontario Breeding Bird Atlas

About

The goal of the Ontario Breeding Bird Atlas is to map the distribution and relative abundance of the approximately 300 species of breeding birds in the province. The Atlas is a collaborative undertaking of Ontario Nature, Birds Canada, Canadian Wildlife Service – Ontario Region, Ontario Field Ornithologists and the Ontario Ministry of Natural Resources. A volunteer-based effort, the Atlas uses a rigorous approach to determine the distributions and populations of bird species breeding in Ontario, and changes over time.

This enormous project is achievable only through the mass participation of the province’s birders. While data collection for the most recent Atlas was completed in 2025, we encourage birders to continue to submit their sightings through eBird so that these data can be accessed and used by scientists and conservation practitioners.

Yellow warbler © Ken Janes

Atlas-3

Data collection for Ontario’s third Breeding Bird Atlas (Atlas-3) spanned five years beginning on January 1, 2021 and concluding on December 31, 2025, exactly 20 years after Atlas-2 (2001–2005) and 40 years after Atlas-1 (1981–1985). Atlas-3 is now in its publication phase, with more than 170 volunteer authors writing accounts for every breeding bird species in Ontario, while Atlas staff finalize data analyses and visualizations. Stay tuned for news about the publication of Atlas-3, planned for late 2027! The Atlas will be published online, where it will be freely available, and in hard-copy, soon to be available for purchase via pre-order.

The Atlas-3 dataset is the most comprehensive and up-to-date source of knowledge about the status, distribution and abundance of breeding birds found in Ontario. The dataset is available for download from NatureCounts and provides a valuable resource for conservationists and researchers. Basic data collection involved recording breeding evidence for as many bird species as possible within a 10-by-10-kilometre-square areas. Birders who recognize species by their song also completed five-minute “point counts” designed to index the number of birds nesting in each square.

Trumpeter swan and cygnet © Danny Correia

_{Yellow-bellied sapsucker © Andy Reago & Chrissy McClarren CC BY 2.0}

Atlas-3 Stats

More than 2,000 volunteers logged over 170,000 hours of field work during the Atlas-3 data collection period.
Volunteers submitted over 4.2 million breeding bird records.
294 species were reported with breeding evidence in the province from 2021–2025.
Breeding records were submitted for nearly 5,500 10-kilometre squares: covering areas of the province from Hudson Bay to Pelee Island.
Over 103,000 point count surveys (which quantify species abundance) were conducted and, together with Atlas-2 data, will be used to produce the first province-wide estimates of the change in the relative abundance over the last 20 years.
Over 11,400 special surveys were submitted for cryptic and nocturnal species that are often missed during general birding, including owls, nightjars (eastern whip-poor-will, common nighthawk), and marsh birds (bitterns, rails).

Killdeer guarding nest and eggs © Brian Garrett CC BY-ND 2.0

Past Atlases

Ontario’s first Breeding Bird Atlas (Atlas-1) was carried out from 1981 to 1985 and published in 1987 as Atlas of the Breeding Birds of Ontario. Atlas-1 was produced by Ontario Nature, then the Federation of Ontario Naturalists (now Ontario Nature), and Long Point Bird Observatory. The book is now out of print but available online.

Atlas-2 took place from 2001 to 2005 and was published as Atlas of the Breeding Birds of Ontario, 2001–2005. The edition includes species accounts, photographs, maps and charts for the roughly 300 bird species that breed in Ontario. Print copies are sold out, but the digital version is available free online.

Piping plover and chicks © Paul Janosi

Impact

Atlas data are a critical resource for scientists and conservation and can be used to inform recovery plans for species at risk, environmental assessments, and land use planning.

The Atlas is an invaluable reference for environmental and resource managers and birders alike.

Donate to Support the Atlas

Tommy Thompson Park Birding Hike © Kirsten Dahl

“The atlas is a monumental achievement. Not only is it a stirring example of co-operative research but the detailed results have been presented with a remarkable clarity and style. Invaluable for the thoroughness of its science, the Atlas is also a wonderful book to simply browse. The species accounts are clean, jargon-free, and inviting; the graphics contain a wealth of visual information; and the text is profusely illustrated with photographs of the birds. This book is a must for everyone interested in birds, Ontario, and the natural world.”

– Margaret Atwood & Graeme Gibson