Extreme Variation in the Tails of Adult Harlan’S Hawks
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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.