Identifying US and Canada Red-tailed Hawks

I've been getting a lot of remarks, questions and rebukes over my identifications in regards to subspecies, sometimes in a common species we call the Red-tailed Hawk. Since I can't find a reliable source that complies every single US/Canada subspecies into one manuscript, I might as well write this and link to my identifications where I'm being asked for more information. Photos to be included to show the features I'm talking about. I hope you enjoy and learn something a little new about Red-tailed Hawks. Sources are sighted below.

Eastern Red-tailed Hawk -- Buteo jamaicensis borealis

Range: Central Alberta and Newfoundland south to south-central Texas and central Florida. Confirmed vagrant sightings in Alaska, Yukon, British Columbia (annual), California, Utah and Baja California. Probably would be annual in every Western US state if more eyes were out looking for the oddities.

Head: White supercilium is common. Throat is usually white, streaked or collared; dark throat is rare. Malar/cheek region usually dark.

Upperparts: Scapulars are moderately to heavily mottled white.

Underparts: Lightly to moderately marked bellyband. Barring occurs often on the flanks, rarely anywhere else. Breast almost always white but tawny does occur.

Wings: No rufous on the underwings. Patagials are thin or dull. Limited underwing markings.

Tail: Nearly all individuals have white uppertail coverts. Subterminal band thin to moderate. Partial or incompletely tail banding is uncommon. Nearly all individuals have white tips to the tail.

Morphs: Only light.

Juvenile: Throat almost always white, supercilium often white, bellyband light to moderately-marked.

Photos -- (1) Clear-cut example of borealis. (2) Lightly-marked streak-throated borealis. (3) Clear-cut flying example of borealis. (4) Flying moderately-marked streak-throated borealis.

https://macaulaylibrary.org/asset/35716511#_ga=2.25563518.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/51359071#_ga=2.267893197.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/49386431#_ga=2.230545887.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/96071241#_ga=2.65992173.2114655241.1571538712-1175263981.1555651889

Northern Red-tailed Hawk -- B. j. abieticola

Note: No longer a valid subspecies on iNaturalist because the Clements Checklist does not recognized it, probably due to the publicization of "Birds of Prey of the West/East" by Brian K. Wheeler in 2018, who does not recognize the subspecies due to some borealis exhibiting similar features that were once diagnostic of abieticola. I personally, am a denier of synonymizing the subspecies due to the fact that eBird still recognizes the subspecies and one of the creators is Brian Sullivan who has equal experience to Wheeler in raptor biology. Also if borealis was so closely related to abieticola, why is there slash on eBird for calurus/abieticola and not borealis/abieticola?

Range: Breeds from Yukon and Newfoundland south to Montana and Michigan. Winters from cental Saskatchewan and Nova Scotia south to Louisiana and Georgia. Because of it's range along the eastern Rocky Mountain front, annuals probably winter in Western US but go unnoticed due to its close resemblance to some Western (calurus) Red-tails.

Head: Dark head. Throat streaked, collared or dark. Darker cheek normal.

Upperparts: Light to moderate white mottling on the scapulars.

Underparts: Bellyband moderately to heavily-marked and always black or very brown black, and the bellyband will either have arrow-shaped streaking or blobby blotched markings. Barring often occurs if the bellyband is moderate. Legs are often unbarred. Breast white but can often be tawny or rufous and these individuals often appear incredibly similar to heavily-marked rufous morph Westerns (calurus). Sides of the breast often have black "dribbling" marks.

Wings: Little to no rufous on lighter morphs, but often heavily rufous on rufous-breasted individuals. Patagials thin but darker than normal borealis. Well defined trailing edge. Underwing coverts are almost always whiter than breast with the exception being intergradation with Western Red-tails.

Tail: Similar to Eastern Red-tails except with a broader subterminal band and they are more likely to show partial or complete tail banding.

Morphs: Mostly light but rufous have occurred. Dark morphs are hypothesized.

Juvenile: Nearly identical to borealis but with more variance, including more heavily marked underparts.

Photos -- (1) Clear-cut example of abieticola. (2) Tawny-breasted abieticola. (3) Flying clear-cut example of abieticola. (4). Flying rufous morph abieticola.

https://macaulaylibrary.org/asset/87408001#_ga=2.57662953.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/88975651#_ga=2.57662953.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/80930791#_ga=2.264183119.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/49383721#_ga=2.221592795.2114655241.1571538712-1175263981.1555651889

Western Red-tailed Hawk -- B. j. calurus

Range: Summers from southern Yukon and southwestern Northwest Territory south to central British Columbia and Alberta. Resident from southwestern British Columbia and eastern Alberta to Baja California Sur and western Texas. Winters in central and southern Midwest States. Annual to most eastern US states.

Head: Throat mostly dark, some have streaked, collared or white throats and these variations seem to occur more often in northern Canadian breeding areas or southwestern US deserts.

Upperparts: Very dark brown, white scapular mottling is light and barely visible comparative to other subspecies, however it is visible enough to use as an id feature to distinguish from other Buteo species.

Underparts: Perhaps the most variable subspecies in terms of underpart markings. Bellyband can vary from a few streaks and barring on the flanks to a thick black band across the belly with barring extending into the breast. Though typical bellybands have barring on the flanks and belly.

Wings: Almost all individuals have tawny or rufous underwings that contrast with the whit remiges. Patagials are dark and noticeably thick, making a huge "U" shape cut on the humerus region. If the bird is in wing, these two features are key to whether your Red-tailed is Western or not.

Tail: Incredibly variable from the "classic" all red-tail with thin subterminal band to a thickly banded tail with no distinct subterminal band. Also note where the wingtips end on the tail. Eastern/Northern Red-tails have wingtips barely extending past the uppertail coverts while calurus can extend from midway across the tail to the tail tips.

Morphs: Light, Rufous, Intermediate (only juveniles) and Dark. However light morphs dominate other morphs and from a compilation of photos I did for research about 96% of all calurus Red-tails are light morphs and 3% are rufous morphs.

Juvenile: Throat usually dark but younger individuals may have white throats that resemble borealis or abieticola. To distinguish light morphs from other subspecies, look for heavily marked bellyband and underwings. Only subspecies that have intermediate and dark morphs which is heavy markings on the breast (intermediate) or black underparts with white streaking, similar to Harlan's juveniles (dark).

Photos (I finally get to use my own!) -- (1) Dark-throated moderately-marked light morph calurus. (2) Tawny-breasted heavily-marked light morph calurus. (3) Lightly-marked calurus. (4) Dark morph juvenile calurus. (5) Heavily-marked rufous morph calurus. (6) Lightly-marked rufous morph calurus. (7) Flying molting very lightly-marked light morph calurus -- note thick patagials. (8) Flying typical light-morph calurus. (9) Flying dark morph calurus -- note that this was a breeder I observed all season and if you see something like this in the field and this is your only shot, best identify it as rufous/dark morph. (10) Dark morph calurus with very thick subterminal band.

https://macaulaylibrary.org/asset/114078141#_ga=2.201850322.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/119750351#_ga=2.29769212.2114655241.1571538712-1175263981.1555651889
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https://macaulaylibrary.org/asset/97549721#_ga=2.225244505.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/141548871#_ga=2.58520169.2114655241.1571538712-1175263981.1555651889'

Alaska (Western) Red-tailed Hawk -- B. j. alascensis

Note: Probably not a valid subspecies but no efforts have been made to synonymized it with calurus, which is my personal third reason why I disagree with the abieticola invalidation. Even the facebook group "Red-tailed Hawk of Western Canada" has admitted that "there's very little distinguishing features between calurus and alascensis, if any, thanks to the observers on our group." The Alaskan Red-tailed is supposed differs with having either a rosy pink breast or tawny-rufous heart-shaped breast markings, smaller size and shorter tail with more individuals exhibiting tail bands.

Range: Rarely found inland but lives from about Juneau, Alaska south down the Alexander archipelago, Queen Charlotte Islands and Vancouver Island. Wheeler (2018) has alascensis summer in Alexander archipelago and wintering on Vancouver Island and the Puget Sound, but I'm debatable on how he deduced that.

Head: Dark or streaked throat, similar to calurus.

Upperparts: Light or moderate white or even buff scapular mottling.

Underparts: Bellyband markings vary considerably from light to heavily marked. Barring occurs across the belly in most individuals. Conflicting sources state that alascensis has a rosy pink breast unlike other subspecies (Clark 2017) or heart-shaped breast streaking (Wheeler 2018). Whether the case is one or another, it appears the consistency though for the subspecies is look for darker breast than belly (if you were to remove the bellyband markings).

Wings: Underwings are seemingly incredibly similar to calurus; dark, thick patagials and rufous coverts that clash with the white remiges.

Tail: Variable. Museum specimens show partial banding to full tail banding. Moderately-thick subterminal band.

Morphs: Seemingly only light.

Juvenile: Similar to calurus but apparently darker overall with wider tail banding.

Photos -- (1) Possible alascensis. (2) Another possible alascensis. (3) Possible flying alascensis.

https://macaulaylibrary.org/asset/22418541#_ga=2.195874927.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/154790291#_ga=2.267194445.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/53994671#_ga=2.234682589.2114655241.1571538712-1175263981.1555651889

Fuertes or Southwestern Red-tailed Hawk -- B. j. fuertesi

Note: It is being debated on whether or not this is a valid subspecies as it appears to be a even less lightly-marked borealis. Though juveniles appear like borealis and the wingtips extend far past the uppertail coverts which is a feature much more similar to calurus.

Range: Arizona to Oklahoma and Texas. Vagrant to Arkansas, Louisiana, California and Nevada.

Head: White throat in most individuals but streaked, collared and dark throats have been spotted. Cheek is normally dark like in borealis.

Upperparts: Light to moderate whitish or buff scapular mottling.

Underparts: Very little to no bellyband and if markings do show, it's only two or three streaking marks. Arizona individuals appear to have more streaking (more being visually similar to a very lightly marked borealis) and even barring on rufous washed flanks.

Wings: Underwings completely white with the exception of thin but dark patagials and "chevrons" where the primary coverts end.

Tail: Tail is very similar to molting borealis/calurus, meaning it's not as red as other Red-tails and if a subterminal band is present, it's very thin.

Morphs: Only light morphs.

Juvenile: Similar to borealis but with longer wings and bellyband has a distinct "V" shaped patterning where borealis is just streaking.

Photos -- (1) Arizona fuertesi -- note slight rufous wash. (2) Arizona fuertesi on the far end of markings. (3) Flying Texas fuertesi on the far end of markings. (4) Flying Arizona fuertesi.

https://macaulaylibrary.org/asset/114896381#_ga=2.196605423.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/22509541#_ga=2.226865246.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/40878611#_ga=2.28777087.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/20812731#_ga=2.250607045.2114655241.1571538712-1175263981.1555651889

Florida Red-tailed Hawk -- B. j. umbrinus

Range: Resident to Florida Peninsula. Vagrant to southeastern Georgia.

Head: Throat usually streaked or dark. Head dark.

Upperparts: Light white scapular mottling and well defined upperparts scalloping.

Underparts: Bellyband is typically moderately-marked but can be lightly-marked. Barred often occurs on the bellyband. Breast is normally rufous with light belly, putting on a very alascensis look but by range, it's incredibly unlikely they're the same.

Wings: Dark patagials that vary in width but is normally thin. Underwing coverts are rufous washed.

Tail: Little variation, typically dark red with moderately-thick subterminal band.

Morphs: Light only.

Juvenile: Similar to calurus juvenile variation, except without intermediate or dark morphs. Some can be extremely heavily marked.

Photos -- (1) Heavily-marked umbrinus -- note rufous breast and light belly. (2) Similar umbrinus features (3) Flying umbrinus (4) Heavily-marked juvenile umbrinus.

https://macaulaylibrary.org/asset/42813881#_ga=2.33429117.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/141937951#_ga=2.260444238.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/23392821#_ga=2.260444238.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/49439481#_ga=2.58528361.2114655241.1571538712-1175263981.1555651889

Krider's Hawk -- B. j. kriderii

Range: Breeds from southern Alberta and Ontario to northeastern Colorado and Iowa. Winters from eastern Colorado and southern Minnesota to eastern Texas and Florida. Can be vagrants to adjacent states of breeding/wintering ranges.

Head: Varies but is normally very whitish. Palest form has nearly completely white head. Darkest form has dark cheek and crown.

Upperparts: Heavy white scapular mottling and scalloping pattern is well defined on the rest of the upperparts.

Underparts: Little to no markings on the underparts and whatever markings an individual may have will be a few streaking. Underparts may have a buffy look, especially when compared side-by-side with the incredibly similar light morph Harlan's.

Wings: Patagials nearly none existent and thin with completely white underwing coverts. When compared to Harlan's look for buffy underparts, banded remiges and reddish-white tail with no other markings.

Tail: Variable with half of the tail being red to completely white. If the rectrices have a white base and reddish tail extends past half the tail, that's a solid candidate for Eastern X Krider's intergrade.

Morphs: Light only.

Juvenile: Heads are typically whiter than adults and white upperparts mottling is even more noticeable. Tail with whitish with banding.

Photos -- (1) Dark Krider's Hawk. (2) Lightest form Krider's. (3) Flying intermediately dark Krider's -- note buffy underwings. (4) Juvenile Krider's. (5) Flying juvenile Krider's.

https://macaulaylibrary.org/asset/109267071#_ga=2.59160046.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/30529471#_ga=2.221634011.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/109377501#_ga=2.24056441.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/37820921#_ga=2.223885528.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/76574721#_ga=2.223885528.2114655241.1571538712-1175263981.1555651889

Harlan's Hawk -- B. j. harlani

Range: Breeds mostly in Alaska and Yukon but recent evidence suggest they may breed throughout Canada all the way to North Dakota. Winters throughout western and central US.

Overall body difference: Besides I find Harlan's such a unique bird, I'm not going to go through all the body part features. All you need to know is; they are either black and white or cool brown and white, tail is incredibly variable from reddish mottled to brown mottling to white with reddish tip. Light morph adults can appear incredibly similar Krider's and are often misidentified in Western US but they differ with colder brown tones, white tail with mottled tail (usually in light morphs) and lack of buffy underwings. Harlan's also frequently show unbanded remiges and thicker patagials. Some Harlan's have Some juveniles can appear very calurus-looking but they differ with having "V" shaped tail banding.

Morphs: Around 84% are dark morph or intermediate morphs and the rest are light.

Photos -- (1) Light morph Harlan's. (2) White-spotted dark morph Harlan's. (3) Same dark morph Harlan's but shows awesome tail pattern. (4) Intermediate morph Harlan's. (5) Flying juvenile intermediate morph Harlan's. (6) Dark morph Harlan's.

https://macaulaylibrary.org/asset/73157161#_ga=2.28774783.2114655241.1571538712-1175263981.1555651889
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https://macaulaylibrary.org/asset/119476081#_ga=2.65919597.2114655241.1571538712-1175263981.1555651889

Intergrades

We know for a fact that ranges overlap and intergrades do occur. Identifying them is the hard part because of feature overlapping among subspecies, so trying to weed out what's normal for one subspecies and not for another and trying to confirm it as an intergrade is either incredibly hard or impossible. Here's a list of intergrades that can or have occurred.

Western (calurus) X Harlan's
Northern (abieticola) X Harlan's
Western X Eastern (borealis)
Eastern X Krider's -- Most common intergrade
Northern X Eastern
Western X Alaska (alascensis) -- Probable
Eastern X Fuertes (fuertesi) -- Probable
Western X Fuertes -- Probable

Photos -- (1) Probable Western X Eastern intergrade (2) Probable Eastern X Krider's intergrade. (3) Probable Northern X Eastern intergrade -- note, though identified as abieticola, the bellyband is brownish and not the jet black typical of the subspecies, suggesting some intergradation but that can't be proven. (4) Harlan's X Western/Eastern or unusual light morph Harlan's. (5) Probable Northern X Harlan's intergrade.

https://macaulaylibrary.org/asset/119765151
https://macaulaylibrary.org/asset/109391161#_ga=2.201199853.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/42791171#_ga=2.268898482.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/80131711#_ga=2.20846203.2114655241.1571538712-1175263981.1555651889
https://macaulaylibrary.org/asset/172500461

Literature Sourced:

  • Clark, William S. (2014) -- Harlan’s Hawks are & have been Breeding within the Red-tailed Hawk Range in Western Canada.
  • Clark, William S. (2014) -- Harlan's Hawk differs from Red-tailed Hawk, especially in plumages
  • Clark, William S. (2018) -- The Alaska Red-tailed Hawk
  • Ligouri, Jerry (2004) -- Dark Red-tailed Hawks
  • Ligouri, Jerry and Brian L. Sullivan (2010) -- A Study of Krider's Red-tailed Hawk
  • Schmoker, Bill and Jerry Ligouri (2010) -- Photo Recovery of Harlan's Red-tailed Hawk in Colorado and Alaska
  • Sullivan, Brian L. and Jerry Ligouri (2010) -- A Territoral Harlan's Hawk (Buteo jamaicensis harlani) in North Dakota, with Notes on Summer Records of this Subspecies from the Northern Great Plains
  • Sullivan, Brian L. (2011) -- Apparent Eastern Red-tailed Hawk (Buteo jamaicensis borealis) nesting in Alaska
  • Ligouri, Jerry and Brian L. Sullivan (2014) -- Comparison of Harlan's with Western and Eastern Red-tailed Hawks
  • Ligouri, Jerry and Brian L. Sullivan (2014) -- Northern Red-tailed Hawk (Buteo jamaicensis abieticola) Revisited
  • Wheeler, Brian K. (2018) -- Birds of Prey of the East
  • Wheeler, Brian K. (2018) -- Birds of Prey of the West

Publicado por birdwhisperer birdwhisperer, 01 de noviembre de 2019

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