EXTREME VARIATION IN THE TAILS OF ADULT HARLAN’S HAWKS
William S. (Bill) Clark Some adult Harlan’s Hawks have tails somewhat similar to this one
Bob Dittrick
But many others have very different tails, both in color and in markings Harlan’s Hawk type specimen. Audubon collected this adult in 1830 in Louisiana (USA) and described it as Harlan’s Buzzard or Black Warrier - Buteo harlani
It is a dark morph, the common morph for this taxon. British Museum of Natural History, Tring Harlan’s Hawk Range They breed in Alaska, Yukon, & ne British Columbia & winter over much of North America. It occurs in two color morphs, dark and light. The AOS considers Harlan’s Hawk a subspecies of Red- tailed Hawk, Buteo jamaicensis harlani, but my paper in Zootaxa advocates it as a species. Clark (2018) Taxonomic status of Harlan’s Hawk Buteo jamaicensis harlani (Aves: Accipitriformes) Zootaxa concludes: “It [Harlan’s Hawk] should be considered a full species based on lack of justification for considering it a subspecies, and the many differences between it and B. jamaicensis, which are greater than differences between any two subspecies of diurnal raptor.” Harlan’s Hawk is a species:
1. Lack of taxonomic justification for inclusion with Buteo jamaicensis. 2. Differs from Buteo jamaicensis by:
* Frequency of color morphs; * Adult plumages by color morph, especially in tail pattern and color;
* Neotony: Harlan’s adult & juvenile body plumages are almost alike; whereas those of Red-tails differ.
* Extent of bare area on the tarsus. * Some behaviors. TYPE SPECIMEN - Upper tail is medium gray, with a hint of rufous and some speckling, wavy banding on one feather, & wide irregular subterminal band. I have not found a similar tail on more than 700 adult Harlan’s Hawks. British Museum of Natural History We expect that the tail color and patterns of adult buzzards to be rather constant. Red-shouldered Hawk Gray Hawk
Broad-winged Hawk Augur Buzzard
Common Buzzard Zone-tailed Hawk Harris’s Hawk (Parabuteo unicinctus) adult tails Show variation, particularly white markings or banding
But the general pattern and color are constant. RED-TAILED HAWKS Tails of adult Red-tails vary little; >99% are like one of the six below Texas Texas RoyalBC
British Columbia Texas British Columbia 1st mention of harlani tail variation Taverner 15 & 22 are juvenile tails (1927): XXX Eight feathers from different adults are gray or rufous & grizzled, mottled, or XXX banded.
Taverner, P. A. 1927. A study of Buteo borealis, the Red- tailed Hawk, and its varieties in Canada. Victoria Mem. Mus. Bull. No. 48 Biol. Series 13:1-25. Most NA bird They usually field guides show only gray show only a tails few of the many variations of adult Harlan’s Hawk’s tails Even specialty raptor guides HAWKS show only a few of the II many variations in the tail pattern of adult Harlan’s Hawks
Peterson series: Hawks To better understand Harlan’s Hawks, I captured, photographed, and examined in hand 36 hawks & collected hundreds of similar photos from raptor banders and rehabilitators.
Mike Tichner – WS Clark Mike Blom Rocky Mt. Raptor Program I have examined & photographed >1000 Harlan’s Hawk specimens in all major North American museums & many others
Can M Nat ADULT HARLAN’S HAWK TAILS Few museum collections have enough adult specimens to show the large range of variation in their tails. Note that no two tails are exactly alike!
Royal Alberta And that Museum many show some rufous
U of Iowa U. of Michigan has 149 adult specimens Six museums have 20 to 29 specimens Seven museums have 10 to 19 specimens 43 museums have 1 to 9 adult specimens
Museum of Southwest Biology, U. of New Mexico ADULT HARLAN’S HAWK TAILS Only 7 museum collections have enough adult specimens to show the large range of variation in their tails. NOTE THAT NO TWO TAILS ARE EXACTLY ALIKE! Field
And that many show some rufous ADULT HARLAN’S HAWK TAILS Collections with only 1 adult Harlan’s
Boise State U Golden Gate Raptor Nat. F&WS For. Lab
NC State Mus. Cal State LB P-Fund Peabody (Yale) ADULT HARLAN’S HAWK TAILS Collections with only 2 adult Harlan’s
Cal Academy Burke Museum, U. Of Wash.
Slater Museum - U. Phil. Acad of Nat. Sciences Puget Sound My article in Birding Clark 2009 All Harlan’s whose tails are shown are pure harlani (not hybrids). Dark adults (>90%) & easily ID’d
Blackish plumage with white bases, often usually forming white breast marks, one or more unbanded secondaries, whitish under tails, & other traits. All Harlan’s whose tails are shown are pure harlani (not hybrids). Light adults (< 10%) & easily ID’d
Al Hinde
White throat & streaks on forehead. Often one or more secondaries unbanded or widely banded. Blackish markings on white underparts and under wing coverts All adult Harlan’s whose tail shown are pure harlani & easily distinguished
Can M Nat Field
Light-morph Dark-morph Tails can be grouped into five types:
Bob Dittrick U Mich Can M Nat
Gray Gray banded Rufous Royal BC Can M Nat MCZ
Rufous banded Mixed TAIL MARKINGS – dark mottling FIELD BYU
UMICH CMN TAIL MARKINGS – grizzling (paint spatter) OU NC STATE M
UMICH WFVZ TAIL MARKINGS – dark streaks MVZ UMICH
BELL UMICH TAIL MARKINGS – banding BYU KU MSB
UMICH OU KU TAIL MARKINGS – subterminal band
BYU WFVZ UMICH
No band Narrow Incomplete UMICH P-FUND UMICH
Wide Wider Very wide Variation in paler gray tails Field U Kansas Royal Sask
Can M Nat U Iowa Bob Dittrick Variation in darker gray tails Field MCZ Cal Acad S
USNM U NE M Bob Dittrick TAIL COLOR –Gray-brown. Considered as gray or gray banded CAS CMN FRANK NICOLETTI
OU UIOWA CMN Variation in gray banded 1 BYU David Mindell Rehab USNM
U Mich WS Clark BYU Bob Dittrick Variation in gray banded 2
U Kansas U Mich BYU U Iowa
U Mich U OK LSU U Kansas Variation in rufous 1 Mike Blom Carole Hallett R Chamberlain
Can M Nat Al Hinde Carole Hallett Variation in rufous 2
Royal Alberta Ted Swem U Wis Den Mus
U Mich Field USNM Variation in rufous banded 1 WS Clark Gary Searing Bell WS Clark
WFVZ WFVZ U Mich USNM Variation in rufous banded 2 Royal BC ANS Phil U Kansas Bell
Perot Mus Can M Nat Royal Alb. Field Spread tails courtesy of Bill Voelker Jim Lish prepared this composite using two of Bill Voelker’s pics Red-tail adult - Harlan’s adult
Harlan’s on the right shows wider and wavier banding, thicker at base. A few adult Red-tail specimens (4 out of > 1000) have harlani-like tail markings All four were PA CA otherwise pure adult CAR LACo Red-tails. Is this due to gene flow with harlani? Or chance odd expressions of U Mich CAR ancestral Buteo traits?
MICH FL Mixed - Pattern and color can also vary among feathers in some tails. MCZ Can M Nat MCZ
U COLO Mike Blom U OKLA Mixed 2- Pattern and color can also vary among feathers in some tails. Frank Taylor Royal Ont MVZ
Bob Dittrick U of MO Rehab OR Pattern and color can also vary in individual adult tail feathers MCZ Royal Ont Rehab BC Can M Nat Dark and light- morph adults can have similar tails
Royal Saskatchewan Museum Number and percentage of each type of adult tail, from a sample of 635 photos: Gray: 336 53% Gray banded 67 11% Rufous 68 11% Rufous banded 76 12% Mixed 88 13%
In this presentation, I have shown 117 different adult tails, no two of which are alike. Juveniles’ tails also show variation Royal AB MVZ U Kansas WS Clark USNM
Burke Bell Frank Nicoletti Field AMNH
Sue LSU USNM Royal Sask WS Clark Cottrell Tails of dark juveniles sometimes show pale spots on the tips
Jim Lish Some juvenile Harlan’s Hawks have adult-like tails Buzz Hull ROM Betsy Rosencrans UWis
Ryan Brady Buzz Hull Step Wilson Adult tails can vary in color and pattern with age David Mindell took 3 nestling Harlan’s Hawks from sw Alaska (1 in 1981 and 2 in 1982) and raised them in captivity
David Mindell
Red Devil Sterling Wassillee David later sent me photos of them as adults in late 1983
Wassillee
Red Devil Sterling
All photos by David Mindell All three were made into specimens and are now in the Monty Beane Museum at BYU
Red Devil– Sterling– Wasillee– BYU 8160 BYU 8306 BYU 8161
I also took close-up photos of their upper tails at the BYU museum. I compared these specimen tail photos to the ones David sent me earlier for all three:
1983 1986
Red Devil– BYU 8160
The banding pattern differs, especially on the outer rectrices. The subterminal band on the central feathers became wider. I compared these specimen tail photos to the ones David sent me earlier for all three:
1983 1986
Sterling– BYU 8306
The banding pattern differs, especially on the central feathers, and there is less rufous wash overall later. I compared these specimen tail photos to the ones David sent me earlier for all three:
1983 1986
Wasillee– BYU 8161
The banding pattern is similar, but there seems to be more brown wash on the later tail. Cody Fields has a Harlan’s Hawk used for falconry. He took these photos of its adult tail in two subsequent years.
2010 2011
The banding pattern is subtly different; absent near tip on center feathers in 2011 Rob Domenech captured a Harlan’s Hawk and put a satellite transmitter on it. He later re-caught it and took the transmitter off. December 2013 January 2016
The banding pattern is subtly different; look at T6 right. In summary, tails of adult Harlan’s Hawks show a huge range of variation, with no two tails alike. More than any other raptors, indeed more than any other bird. Tail variation is a trait of harlani
Why and how do they show such variety in their tails? New DNA techniques, including whole genome sequencing, should be able to identify the genes that are responsible for this extreme variation.
The genes responsible for this variation should differ among individual adult Harlan’s Hawks. Thanks to curators and collection managers of the museums in the next slides for permission to study their precious bird skin resources.
Thanks to many banders and rehabbers for the use of their photos, especially: Mike Blom, Ryan Brady, Ritchie Chamberlain, Sue Cottrell, Bob Dittrick, Rob Domenech, Cody Fields, Carole Hallett, Al Hinde, Buzz Hull, Jim Lish, David Mindell, Frank Nicoletti, Betsy Rosencrans, Gary Searing, Ted Swem, Frank Taylor, Mike Tichner, Bill Voelker, & Step Wilson. Museums visited
Academy of Natural Sciences, Philadelphia; American Museum of Natural History; Arkansas State U; Beaty Biodiversity Museum, U. British Columbia; Bell Museum (U. of Minn); Boise State U bird collection; Burke Museum (U of WA); California Academy of Science; California State U Long Beach bird collection; Canadian Museum of Nature; Carnegie Museum of Natural History; Cleveland Museum of Natural History; Cincinnati Museum of Natural History; Conner Museum, Wash. State U; Delaware Museum of Natural History; Denver Museum of Nature & Science; Field Museum; Golden Gate Bird Obs; Heard Natural History Museum; Houston Museum of Natural Science; LSU Museum of Natural Science: Ornithology; Michigan State U; Milwaukee Public Museum; Monte L. Bean Museum (BYU); Museum of Natural History, U of Iowa; Museum of Southwestern Biology (U of NM); Vertebrate Zoology. Museums visited (Cont.)
Museum of Vertebrate Zoology (U of CA); Museum of Wildlife & Fish Biology (UC Davis); Museum of Zoology, U of Mich; Natural History Museum of LA County; Nebraska State Museum; Oklahoma State U; Noble OK Museum, U of Okla.; North Dakota State U; Ohio State U; Over Museum, SD; Peregrine Fund; Perot Museum of Natural History; Royal Alberta Museum; Royal British Columbia Museum; Royal Ontario Museum; Royal Saskechewan Museum; San Diego Natural History Museum; Santa Barbara Natural History Museum; Slater Museum (U. of Puget Sound); South Dakota State U; Tulane U; WFSD collection, Texas A & M; UCLA – Dickey Bird and Mammal Collections; U of AK Museum; U of AB bird collection; U of AZ bird collection; U of CO Museum of Natural History; U of Kansas Natural History Museum; U of MO bird collection; U of NE State Museum; U of WI; U. S. National Museum; Utah Museum of Natural History; Western Foundation of Vertebrate Zoology; Wright Zoological Museum, U. of Mont; Yale Peabody Museum; Yukon Parks. THANKS FOR YOUR ATTENTION
Bill Voelker
Thanks also to The Peregrine Fund (especially Lloyd Kiff, Chris McClure, & Travis Rosenberry) for making this presentation available on their Global Raptor Information Network (GRIN) web site.