Checklist of Recognizable Forms of Ontario Birds

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:

Recognizable Form

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.

Scientific Name

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.

Nominate Subspecies

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.

Subspecies Group

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* 

__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) 

__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)

__Inland race (inornatus) 
__Coastal race (nominate semipalmatus)*

__North American race (hudsonicus) 
__White-rumped races (nominate phaeopus group) 

Baird's Sandpiper 
__Buff or typical morph 
__Gray morph 

__Hudson Bay race (hudsonia) 
__Short-billed races (schinzii and arctica) 

__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.

“Snyder‘s” Great Horned Owl. Photo: Jean Iron

Ruff, red morph. Photo: Jean Iron

“Yellow” Palm Warbler of the eastern subspecies, Dendroica palmarum hypochrysea on 19 April 2005. Photo: Ken Newcombe

A blue morph “Lesser” Snow Goose Chen caerulescens caerulescens on 11 November 2005. Photo: Jean Iron