by Ron Pittaway
This page is provided by Ron Pittaway who has studied and documented recognizable forms of Ontario birds for many years. This checklist first appeared in the August 1991 issue of Ontario Birds 9(2):49-55 and revised again in the October 1996 issue of OFO News 14(3):4-5. The checklist was updated on 22 October 2006.
Please contact Ron if you have further questions. Ron Pittaway, 9 Lichen Place, Toronto ON M3A 1X3 phone (416) 445-9297, or
The list follows recent taxonomic decisions by the American Ornithologists’ Union including the 47th Supplement in the Auk 112(3):926-936, 2006. However, Thayer's Gull is treated here as a subspecies of the Iceland Gull following The Birds of Canada by Earl Godfrey (1986) and the Annotated Checklist of the Birds of Ontario by Ross James (1991). Hybrids are not included, except Brewster's and Lawrence's Warblers because they have long been considered recognizable forms. Many English names have been updated, but there is no authority on the English names of recognizable forms. Most scientific names of subspecies follow Godfrey (1986) and James (1991); both are excellent sources of information on subspecies. Ron Pittaway's series on recognizable forms (some co-authored with artist Peter Burke) in Ontario Birds has detailed information on many of the forms listed here. Forms treated to date are followed by a reference to Ontario Birds in the checklist for your convenience. The following explains the terms in the checklist:
A neutral term that includes any subspecies, subspecies group, morph, etc. that is identifiable in the field. A few forms (as are some species) are distinguishable in the field only under ideal circumstances; for example, the subspecies of the Common Eider. Recent studies indicate the forms of the Red Crossbill comprise a number of cryptic (hidden) species, best identified in the field by their diagnostic vocalizations. They differ in colour, size, bill size and cone preferences.
A species scientific name is two words italicized in Latin; for example, Limnodromus griseus. The first word is the genus (plural genera); the second word is the species. Closely related species are in the same genus. Some species are divided into subspecies. The third word is the subspecies; for example, Limnodromus griseus hendersoni is the Inland race (hendersoni) of the Short-billed Dowitcher.
Subspecies or Race
The terms are interchangeable. A subspecies is a subdivision (usually subtle differences in colour and/or size) of a species occupying a separate geographical breeding range (or with limited overlap) exclusive of other subspecies. Subspecies intergrade (interbreed) where their ranges meet, whereas species rarely hybridize (interbreed). The subspecies name is most useful where it describes well-defined geographical variation in a species. Well-marked subspecies are identifiable in the field. In the checklist, scientific names of subspecies are enclosed in brackets.
A subspecies whose scientific name is a repeat of the species name; for example, Limnodromus griseus griseus is the nominate subspecies (griseus) of the Short-billed Dowitcher. The nominate subspecies (race) is the first named race; it is not necessarily more important or more typical than any other race of the species.
Intermediates (and intermediate populations) produced by interbreeding between subspecies. Some intergrades are recognizable in the field. Intergrades have an “x” symbol between the subspecies names; for example, griseus x hendersoni.
Very similar subspecies (races) that are combined as one recognizable form. For example, Slate-colored Junco is the English group name for the three subspecies in the nominate hyemalis group. In the checklist, the nominate race or an appropriate Ontario race is chosen for a group's scientific name. A subspecies group can consist of one subspecies.
Morph replaces colour phase as the preferred term. Morphs are distinct forms that coexist in the same interbreeding population, often in the same brood. Morphs usually are not correlated with age, sex or subspecies. In highly variable species, the names chosen for the morphs are arbitrary. Morphs do not have scientific names.
Used instead of intergrade for morphs. Intermediate morph describes indivduals exhibiting continuous variation between light and dark morphs.
Instead of morph, variant better describes extremes of individual variation, mutations, and colour forms caused by diet. Variants do not have scientific names.
* Indicates that the form has not been recorded in Ontario to my knowledge, but is listed because it may occur.
Checklist of Recognizable Forms
of Ontario BirdsTop
Greater White-fronted Goose __Tundra or Prairie race (frontalis) __Greenland race (flavirostris) Snow Goose Ontario Birds 10(2):72-76, 1992 __White morph, Lesser race (caerulescens) __Blue morph, Lesser race (caerulescens) __Intermediate morph, Lesser race (caerulescens) __White morph, Greater race (atlanticus) __Blue morph, Greater race (atlanticus) __Intermediate morph, Greater race (atlanticus) Ross's Goose __White morph __Intermediate morph* __Blue morph* Brant __Atlantic Brant (hrota) __Black Brant (nigricans) Cackling Goose __Richardson's race (hutchinsii) __Cackling race (minima) (escapee) Canada Goose __Giant race (maxima) (breeds S) (large) __Todd's race (interior) (breeds N) (large) __Lesser race (parvipes) (small)* Tundra Swan __Whistling Swan (nominate columbianus) __Bewick's Swan (bewickii) Mute Swan Ontario Birds 12(1):19-26, 1994 __Gray morph __White or Polish morph Green-winged Teal __American race (carolinensis) __Eurasian race (nominate crecca) __Intergrade (carolinensis x crecca) Common Eider __Hudson Bay race (sedentaria) __Maritimes race (dresseri) __Northern race (borealis)* Barrow's Goldeneye Ontario Birds 15(2):81-85, 1997 __Orange-billed female (North America form) __Yellow-tipped bill female (Icelandic form, escapee)* Northern Fulmar __Light morph __Intermediate morphs* __Dark morph* Least Bittern Ontario Birds 14(1):26-40, 1996 __Typical morph __Cory‘s Least Bittern (dark or reddish morph) Double-crested Cormorant Ontario Birds 14(3):124-128, 1996 __Black-crested form (eastern races) __White-crested form (western races) Broad-winged Hawk __Light morph __Dark morph Swainson's Hawk __Light morph __Rufous or intermediate morphs* __Dark morph Red-tailed Hawk Ontario Birds 11(1):23-29, 1993 __Light morph, Eastern race (borealis) __Light morph, Krider's race (kriderii) __Light morph, Western race (calurus) __Rufous morph, Western race (calurus) __Dark morph, Western race (calurus) __Dark morph, Harlan's race (harlani) __Light morph, Harlan's race (harlani)* Ferruginous Hawk __Light morph __Dark morph* Rough-legged Hawk __Light morph __Intermediate morph __Dark morph Merlin Ontario Birds 12(2):74-80, 1994 __Taiga Merlin (nominate columbarius) __Richardson's or Prairie Merlin (richardsonii) __Black Merlin (suckleyi)* Peregrine Falcon __Released Peregrine (anatum-like mix) (breeds) __Tundra Peregrine (tundrius) (migrant) Gyrfalcon __White morph __Gray or intermediate morph __Dark morph Ruffed Grouse __Gray morph __Brown or intermediate morph __Red morph American Coot __Typical morph __White-shielded or Caribbean variant Solitary Sandpiper __Pale-dotted juvenile (nominate solitaria) __Cinnamon-dotted juvenile (cinnamomea) Willet __Inland race (inornatus) __Coastal race (nominate semipalmatus)* Whimbrel __North American race (hudsonicus) __White-rumped races (nominate phaeopus group) Baird's Sandpiper __Buff or typical morph __Gray morph Dunlin __Hudson Bay race (hudsonia) __Short-billed races (schinzii and arctica) Ruff __White morph __Red morph __Black morph Short-billed Dowitcher __Eastern race (nominate griseus) __Inland race (hendersoni) __Intergrade (griseus x hendersoni) Wilson's Phalarope __Dull morph male __Bright or Pied morph male Pomarine Jaeger __Light morph __Intermediate morph __Dark morph Parasitic Jaeger Ontario Birds 13(3):123-130, 1995 __Light morph __Intermediate morph __Dark morph Long-tailed Jaeger __Light morph __Intermediate morph __Dark morph* Mew Gull __North American race (brachyrhynchus) __European race (nominate canus)* California Gull _Dark-mantled race (californicus) _Light-mantled race (albertaensis) Iceland Gull Ontario Birds 10(1):24-26, 1992 __Greenland race (nominate glaucoides) __Kumlien's race (kumlieni) (intergrade) __Thayer's race (thayeri) Lesser Black-backed Gull __British race (graellsii) __Intermediate race (intermedius) __Scandinavian race (nominate fuscus)* Eastern Screech-Owl Ontario Birds 13(2):66-71, 1995 __Gray morph __Brown or intermediate morph __Red morph Great Horned Owl Ontario Birds 11(2):64-69, 1993 __Nominate race (virginianus) __Snyder's race (scalariventris) __Arctic race (subarcticus) __Labrador race (heterocnemis) Northern Flicker __Yellow-shafted Flicker (luteus group) __Red-shafted Flicker (collaris group) __Intergrade (luteus x collaris) Horned Lark Ontario Birds 12(3):109-115, 1994 __Prairie race (praticola) __Northern race (nominate alpestris) __Hoyt's race (hoyti) American Robin __Nominate race (migratorius) __Black-backed race (nigrideus)* Cedar Waxwing Ontario Birds 9(1):7-8, 1991 __Typical morph __Orange-banded variant (diet) Blue-winged x Golden-winged Warbler __Brewster's Warbler (dominant hybrid) __Lawrence's Warbler (recessive hybrid) Black-throated Blue Warbler __Northern race (nominate caerulescens) __Appalachian race (cairnsi) Yellow-rumped Warbler __Myrtle Warbler (nominate coronata group) __Audubon's Warbler (memorabilis group) Yellow-throated Warbler __White-lored or Sycamore race (albilora) __Yellow-lored race (nominate dominica) Palm Warbler Ontario Birds 13(1):23-27, 1995 __Western Palm (palmarum) __Yellow Palm (hypochrysea) __Intergrade (palmarum x hypochrysea) Scarlet Tanager __Typical male __Orange variant male (xanthochroism) Nelson's Sharp-tailed Sparrow __Prairie race (nominate nelsoni) __James Bay race (alterus) __Acadian race (subvirgatus)* Fox Sparrow __Red Fox Sparrow (nominate iliaca group) __Slate-colored Fox Sparrow (schistacea group)* __Sooty Fox Sparrow (unalaschensis group) sight record White-throated Sparrow Ontario Birds 9(3):82-83, 1991 __White-striped morph __Tan-striped morph White-crowned Sparrow __Eastern race (nominate leucophrys) __Gambel's race (gambelii) __Intergrade (leucophrys x gambelii) Dark-eyed Junco Ontario Birds 11(3):101-105, 1993 __Slate-colored Junco (hyemalis group) __Oregon Junco (montanus group) __Pink-sided Junco (mearnsi) __Gray-headed Junco (caniceps group) Common Grackle __Bronzed Grackle (versicolor) __Purple Grackle (stonei)* Gray-crowned Rosy-Finch __Nominate race (tephrocotis) __Hepburn's race (littoralis) Red Crossbill __Small-billed race (sitkensis) (hemlock) (breeds) __Resident race (minor) (pine) (breeds) __Bendire's race (bendirei) __Newfoundland race (pusilla) Common Redpoll Ontario Birds 10(3):108-114, 1992 __Southern race (nominate flammea) __Greater race (rostrata) Hoary Redpoll Ontario Birds 10(3):108-114, 1992 __Southern race (exilipes) __Hornemann's race (nominate hornemanni) Pine Siskin __Typical morph __Green variant
I am grateful to Peter Burke, the late W. Earl Godfrey, Michel Gosselin, Jean Iron, Ross James, Ron Tozer and Mike Turner for advice, but the final choices to include in the checklist were mine. I hope you enjoy the checklist. Check off the recognizable forms you see in Ontario. Please report new and rare forms to me.