List of birds of Ontario

This list of birds of Ontario includes all the bird species recorded in the Canadian province of Ontario as determined by the Ontario Bird Records Committee (OBRC). As of July 2021 there were 508 species on this list, 291 of which are known to breed in the province.^[1] Ontario has a considerable variety of bird species. One of the factors in this diversity is the size and range of environments in Ontario. Another is the Great Lakes; many birds use the shores as a stopping point during migration.^[2]

The OBRC Checklist divides the province into the Lowlands, Central, and South review zones and requests documentation of sightings of birds which are rare or accidental in one, two, or all of the zones. Of the 508 species on the list, 177 are noted as rare anywhere in the province and another 108 are rare in one or two of the zones. Eight species have been introduced to North America. One species has been extirpated, one is extinct, and another might be.

This list is presented in the taxonomic sequence of the Check-list of North and Middle American Birds, 7th edition through the 62nd Supplement, published by the American Ornithological Society (AOS).^[3] Common and scientific names are also those of the Check-list, except that Canadian English spellings are used and the common names of families are from the Clements taxonomy because the AOS list does not include them.

The following codes are used to categorise some species:

• (A) Accidental – a species that only occurs in Ontario as a rare vagrant
• (B) Breeding – a species that currently breeds or has bred in Ontario
• (E) Extinct – a recent species that no longer exists
• (Ex) Extirpated – a species that no longer occurs in Ontario, but populations still exist elsewhere
• (I) Introduced – established solely as result of direct or indirect human intervention; synonymous with non-native and non-indigenous