Identification
The information provided below is indented to inform our regularly encountered migratory diurnal raptors. Please let us know if you notice any errors or have any recommendations on how to improve this page!
Osprey - OSPR
Seasonality:
Spring: Late March into May
Fall: August through early October
Behaviours:
Readily crosses water bodies.
Often follows shorelines, including offshore flight lines.
Large size makes for easier spotting, can reach significant heights, but not as frequently as other species.
Notes:
Willingness to fly over water may reduce concentration effects, leading to low counts at local hawk watches compared to other raptors.
Turkey Vulture - TUVU
Seasonality:
Spring: Late March through April. Peaks Mar 23 - Apr 7.
Fall: Late September into early November. Peaks Oct 1 - Oct 25 depending on weather.
Behaviours:
Rarely crosses water.
Large size makes for easier spotting, can reach significant heights, but not as readily as other species. Willing to migrate quite low during strong winds.
Behavioural differences can be seen between migrating and non-migrating Turkey Vultures, with migrants flapping strongly in a linear direction.
Notes:
Black Vulture - BLVU
Seasonality:
Rare in Spring: mid March into May. Peaks mid March to early April. Readily arrives with the earliest Turkey Vultures.
Fall: little indication of fall southbound movements.
Behaviours:
Rarely crosses water.
Disproportionately occurs as "ratty" individuals with damaged feathers, which alters shape clues for identification.
Notes:
Eyes-only detection is harder than you think in moderate-distance Turkey Vulture kettles.
Golden Eagle - GOEA
Seasonality:
Rare in Spring: Mid February to Mid May. Peaks late February through early March and again in late April to early May.
Fall: Mid September through November. Peaks early to mid November.
Some "migrations" involve birds following food sources such as large movements of Sandhill Crane or Snow Goose.
Behaviours:
Willing to cross water.
Often flies at height, and somewhat more inland, than other raptors; however, this is variable. Rarer to see down low when migrating. Smaller raptors may fear this species and avoid them (at times).
Notes:
Adults move south later in the fall than younger birds, and return earlier in spring. Adult migrants in February are likely under detected and clouded by increasing numbers locally in winter.
Bald Eagle - BAEA
Seasonality:
Spring: March through May. Peaks in March and again in early May.
Fall: September through November. Variable peaks September through November depending on weather and ice conditions.
Behaviours:
Readily crosses water. Non-breeding birds may move variably north or south in either season depending on weather. Local birds and non-migratory movements can make counting at some hawk watches difficult.
Large size makes for easier spotting, can reach significant heights.
Notes:
Has been observed chasing other migrants including Turkey Vulture and American White Pelican.
Very late season freeze-out migrations have been recorded.
Very difficult to age with confidence due to the presence of southern nesting birds which may fledge ~6 months before northern nesters. These southern birds can arrive in the Great Lakes as fresh juveniles in May.
Northern Harrier - NOHA
Seasonality:
Spring: March through April. Peaks in mid April.
Fall: September through November. No clear peaks, perhaps variable due to weather concentration effects.
Behaviours:
Readily crosses water, which may reduce detectability.
Migrates at significantly variable heights (very low to very high).
Notes:
Migrants moving at height may give little consideration to geographic features such as bluff faces, ridges or water (especially in fall when water temperatures are higher) leading to reduces concentration of migrants compared to other raptors.
Mississippi Kite - MIKI
Seasonality:
Rare in Spring: May. Correlation noted between significant dragonfly migrations in spring.
Very rare in Fall: correlation may exist between sightings in the Great Lakes and remnant tropical cyclone activity.
Behaviours:
Extremely buoyant.
May cross water.
Notes:
Sometimes confused with Peregrine Falcon, Northern Harrier, Cooper's Hawk or molting Broad-winged Hawk in spring.
Very short 10th primary diagnostic when clearly observed, yet behaviour and flight style should be more readily apparent.
In spring, mottled underwing helps confirm the age of a first cycle bird compared to the clean appearance of an adult. Birds with an advanced body molt can be difficult to age with perched or with brief flight views.
Sharp-shinned Hawk - SSHA
Seasonality:
Spring: March through May. Peaks in April.
Fall: late August through early November. Peaks in early to mid October.
Behaviours:
Very rarely crosses water.
Migrates at significantly variable heights (very low to very high). Due to small size, birds at altitude are very difficult to detect.
Notes:
Further ID notes (juveniles) provided below American Goshawk.
Younger adults for all accipiter's can be identified by orange eyes, with older birds obtaining deep red eyes over time.
Cooper's Hawk - COHA
Seasonality:
Spring: March through early May. Peaks in late March.
Fall: September through early November. Peaks in mid to late October.
Behaviours:
Very rarely crosses water.
Migrates at variable heights. Large counts are rare. Shows less migratory behaviour than Sharp-shinned Hawk.
Notes:
Further ID notes of juvenile accipiter's provided below American Goshawk.
American Goshawk - AGOS
Seasonality:
Spring: March through early May. Peaks in March.
Fall: October through November. Peaks in late October to mid November.
Behaviours:
Rare in migration. Numbers declining at most hawk watches. Historically irruptive.
May cross water.
Migrates at variable heights.
Notes:
Check out this note on historical Goshawk irruptions and possible reasons for their recent decline. When Goshawks Ruled the Autumn Skies - All About Birds article.
Females can be surprisingly large.
Can be confused with large juvenile female Cooper's Hawk or juvenile Red-shouldered Hawk.
Rare "blonde" juveniles readily misidentified as juvenile Red-shouldered Hawk.
Notes on juvenile accipiter ID are provided below. Structural differences noted also apply to adults.
Red-shouldered Hawk - RSHA
Seasonality:
Spring: mid-March through early April. Peaks in mid to late March. Isolated juveniles thereafter.
Fall: October through mid-November. Peaks from mid-October through mid-November.
Behaviours:
Very rarely crosses water.
Often only observed low early or late in the day.
Atypically high occurrences of two birds migrating in proximity to each other in the fall.
Choppy curved-wing flap recalls Accipiter's, rather than the full-wing snappy flap of Broad-winged Hawk or deep/strong flap of Red-tailed Hawk.
Notes:
Numbers declining at most hawk watches.
Frequently confused with molting Broad-winged Hawk in May due to primary molt appearing like an inner primary "window".
Broad-winged Hawk - BWHA
Seasonality:
Spring: mid-March through early April. Peaks in mid to late March. Isolated juveniles thereafter.
Fall: October through mid-November. Peaks between September 9-25.
Behaviours:
Migrates in significant numbers (kettles of hundreds to thousands occur annually).
Very rarely crosses water.
Often only observed low early or late in the day.
Notes:
Very rare dark morph has been recorded several times in the region. More common in the northwest part of the species range.
May migrate at in groups and at significant height due to fear of predation. Attempts to catch them have been made by Bald Eagle, Golden Eagle, Peregrine Falcon and Red-tailed Hawk. Successful capture of a high-flying migrant by a Red-tailed Hawk observed in Ontario.
Unseasonably cold overnight temperatures in during the peak fall flight period in September, within the species range, may stimulate the largest migrations.
Swainson's Hawk - SWHA
Seasonality:
Rare in Spring: early April through May. Peaks in mid to late April.
Rare in Fall: September through early November. Peaks during mid-September and again in early to mid-October.
Behaviours:
May cross water.
Often joins large migrations of Broad-winged Hawks (spring or fall) or Turkey Vultures (fall).
Notes:
Rarely subadult Bald Eagles, at significant height, trick observers into thinking they have a Swainson's Hawk due to the two-toned underwing.
Four primary "fingers" makes for a notably different field impression compared to Red-tailed or Rough-legged Hawk. Surprisingly recalls Broad-winged Hawk at times.
Rough-legged Hawk - RLHA
Seasonality:
Spring: early April through May. Peaks in mid to late April.
Fall: Late September through mid November. Peaks mid October through early November.
Behaviours:
Readily crosses water.
Notes:
If you use social media, be sure to check out the Rough-legged Hawk Project.
Migration involves more east-west movements than other species, leading to more annual variation in seasonal numbers, depending on weather conditions. The bulk of spring migrants often pass to the north of the Great Lakes.
Our only raptor with largely identifiable ages, sexes and plumage morphs.
Top Row: Adults with crisp markings, clearly banded tails, dark terminal band to flight feathers. Females with dark belly. Light morph adults highly variable.
Bottom Row: Juveniles which lack crisp markings. Dark belly less reliable for sexing young birds at this age.
Red-tailed Hawk - RTHA
Seasonality:
Spring: March through April. Peaks in late March to early April.
Fall: mid-September through mid-November. Peaks from mid-October through early-November.
Behaviours:
Rarely crosses water.
Often only observed low early or late in the day.
Notes:
Be sure to check out The Red-tailed Hawk Project for a wealth of information on this species.
Significant confusion has developed in recent years around boreal-nesting abieticola and more southerly nesting borealis subspecies.
Dark morph rare but regular, particularly in western Great Lakes. Rufous-morph very rare. The subspecies status of these birds is unclear. The designation calurus/abieticola is recommended for these ambiguous dark or rufous morph adults in the Great Lakes until more clarity arises.
Some exceptional info on two Great Lakes dark morph RTHA, which were captured and tracked, here!
Harlan's subspecies very rare with most records of harder-to-identify dark juveniles. Dark adults can be very distinctive.
Light morph Harlan's (adult or juvenile) are likely underreported. Further, significant confusion exists around the relationship of the "Krider's" subspecies - which is also very rare but regularly observed in the Great Lakes. Light morph intermediate Harlan's/Krider's nest as close as Manitoba and show intermediate characteristics between published information on each form, and are usually paired with birds that look like typical borealis.
Variation in Light Morph Adult Red-tailed Hawk in the Great Lakes
1
2
3
4
5
6
7
8
9
10
Extremes of variation are readily identified by local birders to subspecies: borealis for birds 1-4, or abieticola for birds similar to 7, 9 or 10. These generalized patterns play out at our southernmost hawk watches were darker northern birds migrate later in spring (late March into April) and appear earlier (early October) than paler southern birds.
Unfortunately there are many examples of nesting birds which ruin the fun, such as abieticola-looking birds nesting in Toronto or northern boreal nesters which match borealis. Thankfully groups like the Red-tailed Hawk project are working at figuring these things out! In the meantime, keep studying and documenting the birds you encounter! The variation is endless, and encountering exceptional individuals can really add to your hawk watching experiences.
American Kestrel - AMKE
Seasonality:
Spring: April through early May. Peaks in mid-April.
Fall: August through early November. Peaks in September to early October.
Behaviours:
Rarely crosses water.
Migrates at significantly variable heights (very low to very high). Due to small size, birds at altitude are very difficult to detect.
Notes:
Reddish light often visible through fanned tail when soaring.
Much more floppy/delicate than Merlin.
Merlin - MERL
Seasonality:
Spring: mid-March through early May. Peaks in late March through mid April. Rarely observed in large numbers in spring.
Fall: August through early November. Peaks in September through early October.
Behaviours:
Readily crosses water.
Often migrates quite low, power flying through a watch site.
May harass everything in sight.
Notes:
Soaring migrants at height are rare but regular, and can be confused with Peregrine Falcon or, in season, Mississippi Kite.
Richardson's or Prairie Merlin very rare, most common in far western Great Lakes. Adult male "Blue Jack" Merlin are frequently confused with the prairie subspecies.
Peregrine Falcon - PEFA
Seasonality:
Spring: mid-March through mid-May. Southern nesting birds arrive in March. Peak of arctic nesting birds in late April through early May. Rarely observed in large numbers during spring migration.
Fall: August through late October. Juveniles of southern nesting birds wander widely in late summer. Peak of arctic nesting migrants from late September through early October.
Behaviours:
Readily crosses water.
Readily migrates at lower heights along strong updrafts along ridges or bluff faces.
Frequently observed soaring at significant height - much more often than Merlin.
Notes:
Isolated birds are regularly observed soaring with Broad-winged Hawk kettles in September. It is unclear at times if these birds are migrants or are contemplating hunting the hawks.
May hunt smaller migrant raptors such as American Kestrel or Sharp-shinned Hawk.
Juveniles sometimes harass other migrating raptors including larger species like Osprey or Turkey Vulture.
Honorary Raptors
These species may migrate with, and/or behave similarly to, our diurnal migrant raptors.
American White Pelican - AWPE
March through May. September and October.
Distinctive size and plumage. Can make impressive kettles soaring to significant heights.
More common further west.
Sandhill Crane - SACR
March and April with smaller numbers both earlier and later. October to early December in fall, with peak numbers corresponding with freeze-out or heavy snow conditions.
May kettle, but less commonly reaches significant heights. Sometimes travels in long, sprawling and slow moving groups.
