First Record of the Common Black-Hawk for California

Thefollowing article is the third in a serieson Californiararities edited by Morlan and Roberson.It isbased on materialssubmitted to the CaliforniaBird Records Committee(CBRC). The descriptionand circumstanceswere edited from the accountsof the observersand havebeen reviewed by them.Roberson prepared the distributionalsummary and Morlan preparedthe identificationsummary. In thisway we hopethat muchimportant information accumulated in CBRC files will become widely available.

Common Black-Hawk Sketch by Tim Manviis

FIRST RECORD OF THE COMMON BLACK-HAWK FOR CALIFORNIA

BRIAN E. DANIELS, 3471 Lama, Long Beach, California 90808 LOREN and DEBRA HAYS, 9896 Argyle, HuntingtonBeach, California92646 JOSEPH MORLAN, 417 TalbotAve., Albany, California94706 DON ROBERSON, 282 Grove Acre Ave., Pacific Grove, California 93950

On 13 April 1985, Danielsand the Haysesfound a Common Black-Hawk Buteoga!iusanthracinus at ThousandPalms Nature ConservancyPreserve, RiversideCounty, California, a lushCalifornia Fan PalmWashingtonia filifera oasiswith a creeklined by Fremont CottonwoodsPopulus fremontii. They firstsaw the hawkat 0700 flyingdownstream about 50 yardsaway. A Common RavenCorvus corax whose nest was nearbyharassed it. The hawk flew back overthe observers(within about 50 feet) and disappearedinto the palmtrees. At about0800 they sawit againabout a half mile upstream.It flew pastthem and then circled higher and higher, disappearingtoward the north. They observedthe bird for a total of about 15 minutes.Efforts to follow it by car were unsuccessful.They, and others,searched for the hawk later that day, but did not find it. The followingdescription was compiled from thoseof the threeobservers: A buteoninehawk aboutthe sizeof a Red-tailedHawk Buteojamaicensis (not directly comparedbut soaringin the samegeneral area) but differingby itsvery broad rounded wingsand short wide tail. It was perhapsthe same length as the adjacentraven but wasnoticeably bulkier and soaredwith a flat flightprofile. Western Birds 20:11-18, 1989 11 COMMON BLACK-HAWK

The entireplumage was black--dull black to coalblack--except for a palewhite patch on the underwingat the baseof the primaries,a broadbright white mediantail band, and a narrowterminal tail band. The white wing patch was not as brightas the tail bandsand waslimited to the basalportions of the outer4 or 5 primaries.The tail bands were seen on both the dorsaland ventralsurfaces; the median band was perhaps5 to 7 timeswider than the terminalband (notedonly by Daniels).The uppertail coverts were particularlyscrutinized (to eliminatethe possibilityof the Great Black-HawkB. urubitinga);they were black. The cere was brightyellow, noticeable even from a distance,the yellowseeming to extendonto the face.The restof the heavilyhooked large bill wasblack. The legsand feet, seenwell when the birdwas overhead, were lemonyellow and extendedin flight to the centerof the mediantail band,emphasizing the tairsshortness. The talonswere black.When the birdwas directlyoverhead, no bandsor jesseswere seen on its legs. L. Hays describeda loud "scree"call. The recordwas unanimously accepted by the CaliforniaBird Records Com- mitteeon the firstcirculation. Daniels and mostCBRC membersdisputed the describedcall, suggestingit was given by the nearby Red-tailedHawk, but L. Haysfelt the call wassimilar to oneshe had heardfrom Common Black- Hawks in Arizona (see below for further discussionof vocalizations). This representsthe firstrecord of the Common Black-Hawkfor California(Roberson 1986).

DISTRIBUTIONAL SUMMARY

The Common Black-Hawkranges from northwesternArizona, southwestern Utah, southernNew Mexico,and westernTexas (Figure 1) to northernSouth America, with isolatedlocal populations in the Caribbean.The northernmost populationsare migratory(A.O.U. 1983). Birdsare presentin Arizona from mid-Marchto earlyOctober (Monson and Phillips1981); thereare no authentic winter records(DeSante and Pyle 1986). At least 150 pairsbreed in the United Statesportion of the hawk'srange, of which80-90% arein Arizona(Schnell 1979, Helen Snyderin litt. to Min- nesotaOrnithologists' Records Committee). A few pairsnest in the DavisMoun- tainsof westernTexas and occasionally along the RioGrande in southernTexas (Schnell1979, TexasOrnithological Society 1984). There are a few nesting recordsfrom the VirginRiver in southwestUtah (Behleet al. 1985). A vagrant wasat ChatfieldState RecreationArea, JeffersonCounty, Colorado, 20-21 June 1980 (Gent 1987). A CommonBlack-Hawk in heavypostjuvenal molt washit by a truckon 18 September1976 at Bemidji,Minnesota. This bird was firstconsidered to be possiblya wild vagrant(Elwell et al. 1978), but it hassince been regarded as a probableescape (DeSante and Pyle 1986). The specieswas offeredcom- merciallyfor sale in the mid-1970s,and the specimenshows asymmetrical molt,fret marks (the result of stress,such as inadequatenutrition) on the juvenal primariesof the left wing,and abnormallyheavy wear on the centralretrices (HarrisonB. Tordoffin litt. to MinnesotaOrnithologists' Records Committee). Thesefacts persuaded the MinnesotaRecords Committee to rejectthe record (R. Janssenpers. comm.). In southern Florida between 1972 and 1976 there were at least four black- hawksthat were originallypublished as Common Black-Hawks,possibly of 12 COMMON BLACK-HAWK

Caribbeanorgin (Abramson1976). However,these birdsdid not have the prominentwhite wing patch of Caribbeanbirds (Ogden I975) and aretreated as escapedbirds, possibly Great Black-Hawks, by the A.O.U.(1983). Wally George (in litt.) observedone of the adultsnumerous times; that bird had whiteuppertail coverts and a whitetail with a blacksubterminal band. These charactersrule out the Common Black-Hawk and are marks of the Great Black- Hawk.In addition,the tail pattern of the immaturebird shown in the published photo(Abramson 1976) suggeststhe birdmay be a second-yearGreat Black- Hawk (seebelow for furtherdiscussion of plumages).These black-hawks have successfullynested in southFlorida (Ogden I975, W. Georgein litt.). Details havenot beensubmitted to the FloridaOrnithological Society Records Com- mitteeand neitherspecies is acceptedon the statelist (Helen Dowling in litt.). The previousrecords nearest California are from the Arizonaside of the ColoradoRiver, southern Nevada, and northwesternBaja California, Mexico. The CommonBlack-Hawk was reported along the ColoradoRiver in Arizona at Parker,near Ehrenberg (ll April 1978 and 5 May 1979, the latterpublished as "possiblyttrttbitinga," Monson and Phillips1981), and in the Bill Williams

Figure1. Approximatebreeding range of Common Black-Hawk(shaded; U.S. range after Schnell1979), with extralimitalnesting (arrows), and recordsof vagrantsmen- tioned in text (asterisks),and the Californiarecord (star).

13 COMMON BLACK-HAWK

Delta from Marchto May 1979 and in summer1981 (Rosenberget al. 1981). There are at leastfive recordsfrom southernNevada (Kingery1980), but the specieshas not attemptedto nestthere (DeSanteand Pyle 1986, contraA.O.U. 1983). Short and Crossin(1967) reportedseeing an adulton 7 April 1967 (not "7 May" as statedby Palmer1988a) nearSan Vicente,northwestern Baja California. Becauseof the numberof recordsjust across the border,a Californiasighting was expected,and this specieswas chosenby 4 of 5 expertsasked by Jehl (1980) to predictthe ten likeliestbirds to be added to the Californiastate list. The mid-Aprildate and the desertoasis locale seem appropriate.A Common Black-Hawkreported ten days later in Joshua Tree National Monument (McCaskie1985) wasjudged by the CBRC to be inadequatelydocumented (Bevier in prep.).

SUBSPECIES

The A.O.U. (1957) regardedUnited Statesbirds as part of the subspecies B. a. anthracinus.The populationfrom Cuba and the Isle of Pines is a subspecies,gundlachii, of the CommonBlack-Hawk, according to the A.O.U. (1983). B. a. gundlachiidiffers from nominateanthracinus by the muchlarger whitepatch on itsunderwing (Bond 1979), itsbrowner overall coloration, and its whitishmalar stripe(Brown and Areadon 1968). Becauseof the sizeof the wing patch and lack of malar stripe,as well as geographicdistribution, we assignthe Californiabird to the anthracinusgroup (A.O.U. 1983), generally regardedas comprisinga singlesubspecies B. a. anthracinus(Blake 1977, Brown and Areadon 1968), with which B. a. utilensisof islandsin the Gulf of Honduras,recognized by Stresemannand Areadon(1979), is synonymized. Accordingto the A.O.U. (1983), populationsfrom Pacificcoastal areas of El Salvadorsouthward are a separatespecies, the MangroveBlack-Hawk B. subtilis(discussed further below), but someauthors (e.g., Palmer 1988a) stilltreat these populationsas subspeciesof B. anthracinus.

IDENTIFICATION SUMMARY

In the United States,the Common Black-Hawkis mostlikely to be con- fusedwith the Zone-tailedHawk Buteo aibonotatus,although dark morphs of otherspecies may bear some resemblance to it (Clarkand Wheeler1987). The Common Black-Hawk resemblesthe BlackVulture Coragypsatratus in that bothbirds are blackwith a white patchat the baseof the primaries(faint on the Common Black-Hawk)and have roundedwings and a shorttail. Both soar on flat wings,but the Black Vulture flaps its wings quickly,while the CommonBlack-Hawk flaps its wings slowly. The tailsof adultCommon Black- Hawks and adult Zone-tailed Hawks both show a broad white band across the center of the tail. The Zone-tailed has one or two additional narrow bands acrossthe baseof thetail. These are usually lacking or concealedby tail coverts on the Common Black-Hawk,but narrowwhite edgeson the tail covertsof the Common Black-Hawkmay give the illusionof narrow bands.On the CommonBlack-Hawk the bandsare whiteon boththe upperand lowersides of the tail, but on the Zone-tailedthe bandson the upper side are gray and

14 COMMON BLACK-HAWK

much lessdistinct. The Common Black-Hawkappears to have a shortertail than the Zone-tailed,but on perchedbirds tail differencesmay be difficultto seeand the clearestdifferences are on the billand legs.The billof the Common Black-Hawkis about30% largerthan that of the Zone-tailedHawk and hasa largeryellow cere connecting to more extensiveyellow lores. The Common Black-Hawk'syellow legsare much longerthan the Zone-tailed's(Stallcup 1985, Friedmann 1950). In the tropics,several other speciesclosely resemble the CommonBlack- Hawk. The MangroveBlack-Hawk replaces the Common Black-Hawkin coastalmangroves along the Pacificcoast from El Salvador(possibly southern Mexico; Davis 1972) southto Peru (A.O.U. 1983). The MangroveBlack- Hawk exhibitssubstantial geographic variation, with three well-marked subspeciesdiffering in the amount of rufousin their secondariesand inner primaries.South American birds (B. s. subtilis)have the mostrufous and El Salvador/Honduras birds (B. s. rhizophorae) have the least; Costa Rica/Panamabirds (B. s. bangsi)are intermediate (Blake 1977, Monroe1968). Otherwise,the MangroveBlack-Hawk is similarto the CommonBlack-Hawk (which also has faint rufous in the secondariesbut not the inner primaries) exceptfor itssmaller size and morewhite in itsunderwing (Brown and Areadon 1968). The Great Black-Hawk of Middle and South America is also quite similar to the Common Black-Hawk. It rangesnorth to northern Mexico,and some previousreports of Common Black-Hawksin Floridaand Arizonahave been suspectedof pertainingto this species.The adult Great Black-Hawk is best distinguishedby its uppertailcoverts, which are white in all populations.It also has longer legs, which nearly reach the tip of the tail in flight, and its underwingsaverage less white than the Common Black-Hawk's.Middle Americanpopulations (B. u. ridgwayi)have two or three white bandson the tail, fairlyconspicuous white barring on the thighs,and slatylores with yellow confinedto the cere (Ridgely 1976). The South American B. u. urubitinga lacksthe thighmarkings, has yellow lores, and hasa singlewhite band across the entire base of the tail connectingto the white uppertailcoverts. The rare Solitary Eagle Plarpyhaliaetussolitarius, whose range broadly overlapsthat of the Great Black-Hawk,is even larger,lacks the white wing patch of the Common Black-Hawk, and has a larger,more projectinghead, often with a bushycrest (Hilty and Brown 1986). All juvenal black-hawksare similarto each other and quite differentfrom immatureZone-tailed Hawks. They have a highlypatterned head with a bold dark malar stripe, and many have a pale superciliumthat contrastswith a darkishcap. Their underpartsare largelybuff or whitishwith heavydark streaks and large teardrop-shapedbrown spots,especially on the flanks and sides of the breast.Their backsare blackishbrown, heavily mottled with white or buff, especiallyon the upperback and nape. On the juvenalCommon Black- Hawk, the tail is whitish,crossed by about 5-8 wavy narrowdark bars.The Great Black-Hawkis similar,but itstail is crossedby 10-14 dark bars(Ridgely 1976, Hilty and Brown 1986). In both species,juvenal plumage is retained through winter and graduallymolted during the next spring,summer, and fall (Palmer 1988a). Unlike the Common Black-Hawk, the Great Black-Hawk has a distinctivesecond-year immature plumage, similar to the juvenal, but 15 COMMON BLACK-HAWK with only 5 or 6 tail bands.In this plumage,the subterminalblackish band is much wider, constitutingabout a fifth of the entiretail length,unlike juvenal plumagesof bothspecies, in whichthe subterminalband is only slighfiy broader than the others(Friedmann 1950). The longerlegs of the Great Black-Hawk remainhelpful in identificationof iramatures.Juvenal Solitary Eagles apparenfiy lackprominent tail barring (Friedmann 1950, Hilty and Brown1986). Juvenal MangroveBlack-Hawks are very similarto juvenal Common Black-Hawks, differingonly in theirsmaller size and possiblyin havingless streaking on the underpartsand morerufous in theirsecondaries and wingcoverts (Friedmann 1950). However,these plumage differences probably vary dependingon the subspecies. JuvenalBroad-winged Hawks Buteo platypterus and GrayHawks B. nitidus are smallerand havestraighter, more even gray-and-brownrather than wavy black-and-whitetail bands.However, the juvenalBroad-winged Hawk varies conspicuouslyin the width of itsproximal tail bands,variation not illustrated in field guides.On such birds,the tail bandsare about equal in width and muchbroader than the narrowwavy bands on the tailsof juvenalblack-hawks. Forbush(1927) and Oberholser(1974) misinterpretedthis variant as a second- yearplumage, and Friedmann(1950) suggestedthat it mightbe transitional, but Johnsonand Peeters(1963) showedthat it wasmerely normal variation in juvenal plumage (cf. also Palmer 1988a,b). Furtherstudy of vocalizationsis needed.Hilty and Brown (1986), Ridgely (1976), and Schnell (1979) statedthat the callsof Common and Great Black- Hawks are distinctive,but descriptionsin other literatureare confusing.The CommonBlack-Hawk typically gives a seriesof shrill,high-pitched, whistled screams best described as "whee-wheee-we-we-we-we" or "fie-fie-flee-fie-fie- fie-fie"with the longestsyllable higher and louderthan the rest(Terrill 1983). These are the high-pitched"spinking" whistled notes describedby Ridgely (1976) and Hilty and Brown (1986) and the sevento eightpiercing staccato, multi-pitchednotes described by Schnell(1979). A harshprolonged cry "ka- a-a-ah, ka-a-a-ah" (Bent 1937) or "haaaaaah" (Petersonand Chalif 1973), a weak, long, high-pitchedwhistle (Edwards 1972), and a night-heron-like squawk(Bent 1937) have alsobeen attributedto the Common Black-Hawk, possiblyin error (cf. alsoSchnell 1988). The voiceof the GreatBlack-Hawk is usuallydescribed as a high-pitchedwhistled scream "wheeeeeeeur" (Hilty and Brown 1986, Ridgely 1976, Petersonand Chalif 1973) or a rasping extendedhigh-pitched whistle (Edwards 1972). Thiscall is givenby bothflying and perchedbirds, but Petersonand Chalif (1973) attributea "keek-keek-keek- keek"to the aerialdisplay of the GreatBlack-Hawk, and Davis(1972) describes this as "ka-ka-ka-keeeo,"with the final "keeeoo"sometimes given alone as a loud scream.

ACKNOWLEDGMENTS

We thank CBRC membersLouis Beylet, LaurenceC. Binford,Jon L. Dunn, Richard A. Erickson,Jeri M. Langham,Guy McCaskie,Benjamin D. Parmeter,and Richard Stallcupfor theircomments in reviewingthis record, and RichardL. Glinskifor helpful commentson an earlierdraft. RobertB. Janssengraciously provided the file on the Minnesotarecord of the CommonBlack-Hawk. Helen P. Dowlingkindly provided infor- mationregarding Florida black-hawks and WallyGeorge forwarded much useful infor- 16 COMMON BLACK-HAWK

mation aboutthose birds.We also thank Stephen E Baileyfor assistancein Morlan's examinationof specimensat the CaliforniaAcademy of Sciences,and Tim Manoils for preparingthe sketch.

LITERATURE CITED

Abramson,I. J. 1976. The BlackHawk (Buteogallusantbracings) in southFlorida. Am. Birds 30:661-662. American Ornithologists'Union. 1957. Check-List of North American Birds. 5th ed. Am. Ornithol. Union, Baltimore, MD. American Ornithologists'Union. 1983. Check-Listof North American Birds.6th ed. Am. Ornithol. Union, Washington, D.C. Behle, W., Sorensen, E., and White, C. 1985. Utah Birds: A revised checklist.Utah Mus. Nat. Hist. Occ. Publ. 4. Bent,A. C. 1937. Life historiesof NorthAmerican birds of prey,part 1. U.S. Nat. Mus. Bull. 170. Bevier,L. in prep. Eleventhreport of the CaliforniaBird RecordsCommittee. W. Birds. Blake, E. 1977. Manual of NeotropicalBirds. Univ. of Chicago Press,Chicago. Bond, J. 1979. Birds of the West Indies. Collins, London. Brown,L., and Areadon,D. 1968. Eagles,Hawks and Falconsof the World. Country Life, Feltham, England. Clark,W., and Wheeler,B. 1987. A FieldGuide to Hawksof North America.Houghton Mifflin, Boston. Davis, L. I. 1972. A Field Guide to the Birds of Mexico and Central America. Univ. of TexasPress, Austin. DeSante, D., and Pyle, P. 1986. DistributionalChecklist of North American Birds. ArtemisiaPress, Lee Vining, CA. Edwards,E. P. 1972. A Field Guide to the Birdsof Mexico.E. P. Edwards,Sweet Briar, VA. Elwell,L., Mathisen,J., and Mathisen,A. 1978. BlackHawk found in Bemidji.Loon 50:31-34. Forbush,E. H. 1927. Birdsof Massachusettsand Other New EnglandStates. Vol. 2. Mass. Dept. Agric., Norwood, MA. Friedmann, H. 1950. The birds of North and Middle America. U.S. Natl. Mus. Bull. 50, part XI. Gent, R 1987. ColoradoField Ornithologists' Records Committee report for 1978-1985. W. Birds 18:97-108. Hilty, S., and Brown, W. 1986. A Guide to the Birds of Colombia. PrincetonUniv. Press, Princeton, NJ. Jehl, J. R., Jr. 1980. Trendsin the state list of California birds. W. Birds 11:103-109. Johnson,N. K., and Peeters,H. J. 1963. The systematicposition of certainhawks in the genusButeo. Auk 80:417-446. Kingery,H. 1980. The springmigration: Mountain West region. Am. Birds34:800-803. McCaskie,G. 1985. The springmigration: Southern Pacific Coast region. Am. Birds 349-351. Monson, G., and Phillips,A. 1981. Annotated Checklistof the Birdsof Arizona. Univ. of Ariz. Press, Tucson.

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Monroe, B. L., Jr. 1968. A distributionalsurvey of the birdsof Honduras.Ornithol. Monogr. 7. Oberholser, H. 1974. The Bird Life of Texas. Univ. of Texas Press, Austin. Ogden, J. C. 1975. The nestingseason: Florida region. Am. Birds29:960-963. Palmer, R. S. 1988a. Handbook of North American Birds. Vol. 4. Yale Univ. Press, New Haven, CT. Palmer, R. S. 1988b. Handbook of North American Birds. Vol. 5. Yale Univ. Press, New Haven, CT. Peterson,R. T., and Chalif, E. L. 1973. A Field Guide to Mexican Birds. Houghton Mifflin, Boston. Ridgely,R. 1976. A Guide to the Birdsof Panama.Princeton Univ. Press, Princeton, NJ. Roberson,D. 1986. Ninth reportof the CaliforniaBird RecordsCommittee. W. Birds 17:49-77. Rosenberg,K., Hubbard,J., and Rosenberg,G. 1981. The nestingseason: Southwest region. Am. Birds 35:966-969. Schnell, J. H. 1979. Habitat managementseries for unique or endangeredspecies. Report 18: BlackHawk (Buteogallusanthracinus). U.S. Dept. Interior,Bur. Land Mgmt.,Technical Note T/N 329, FilingCode 6611. Availablefor $15.95 postpaid from NationalTechnical Information Services, 5285 Port Royal Rd., Springfield, VA 22161. Schnell,J. H. 1988. LesserBlack-Hawk--Voice, in Handbook of North American Birds, (R. S. Palmer, ed.), Vol. 4, p. 382. Yale Univ. Press, New Haven, CT. Short, L. L., and Crossin,R. S. 1967. Noteson the avifaunaof northwesternBaja Cali- fornia. Trans.San Diego Soc. Nat. Hist. 14:281-300. Stallcup,R. 1985. Birdsfor Real. R. Stallcup,Inverness, CA. Stresemann,E., and Areadon, D. 1979. Order Falconiformes,in Check-listof Birds of the World, Vol. 1, 2nd ed. (E. Mayr and G. W. Cottrell,eds.), pp. 271-425. Mus. Comp. Zool., Cambridge,MA. Terrill,S. B. 1983. Common Black-Hawk,in The Audubon Society MasterGuide to Birding(J. Farrand,Jr., ed.), Vol. 1, pp. 232-234. Knopf, New York. TexasOrnithological Society. 1984. Checklistof the Birdsof Texas,2nd ed. (K. Arnold, ed.). Texas Ornithol. Soc., Austin, TX. Accepted 13 January 1989