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j. RaptorRes. 33 (4) :323-326 ¸ 1999 The Raptor ResearchFoundation, Inc.

PRONOUNCED VARIATION IN TARSAL AND FOOT FEATHERING IN THE UPLAND ( BUTEOHEMIIASIUS) IN

DAVID H. ELLIS USGSPatuxent Wildlife Research Center, HCR 1 Box 4420, Oracle,AZ 85623 U.S.A.

NElL WOFFINDEN 210 Engineeringand ScienceBuilding, University of Pittsburghat Johnstown,Johnstown, PA 15904 U.S.A.

PETER L. WHITLOCK P.O. Box 325, Eastham, MA 02642 U.S.A.

P. TSENGEG 307 SweetAvenue No. 7, Moscow,1D 83843 U.S.A.

I•¾ WOP•DS:Upland Buzzard; hemilasius;feather age by comparisonwith Moritsch's (1983) photos of Red- condition;ptilosis. tailed Hawks (B. jamaicensis)which fledge at about 6 wk of age. During 1994, 1995, 1997 and 1998,we locatedover 250 Feather condition wasas follows:69 nestlingshad tars• Upland Buzzard (Buteohemilasius) nests across Mongolia. fully feathered (i.e., feathers extended [or would have In thesenests, we noted considerablemorphological var- extended when fully grown] from the ankle all the way iation in plumage coloration and in leg pterylosisof nest- to the baseof the toes), 32 were three-quartersfeathered lings. Although it is normal for many Buteospecies to and 18 were half feathered. Of the 119 nestlings,16 had display a high degree of color polymorphism, the vari- scattered feathers on their tarsi or feet beyond the zone ability we found in tarsaland foot featheringwas unique of continuous feathering. Among the 69 nestlings w•th and sometimesgreater within a single brood than could fifil tarsal feathering, four had scatteredfeathers between be expected within any naturally occurring raptor spe- or on their toes. Another with only three-quarters cies. feathered tarsi also had scattered feathers on its toes. Of Although Brown and Amadon (1968) illustrated the the 11 nestlings with feathers scattered on their tarsl, Upland Buzzard as bare-legged,their text statesthat the eight were among the 18 nestlingswith tarsi half feath- tarsusis partially feathered and Weick (1980) illustrated ered. For two nestlings, distribution of feathers was dou- partial tarsal feathering. We found that more than half bly odd. The lateral aspectof both tarsi were half feath- of the in Mongolia have fully feathered tarsi (Fig. ered, while the medial sideswere nearly fully feathered. la) while others, sometimes in the same nest, had tarsi In summary, of 119 nestlingswe caretSallyexamined, three-quartersor even half feathered (Fig. lb). Occasion- 50 (42%) had lessthan fully feathered tarsi arid four of ally birds had patchesof feathers or scatteredfeathers on the 69 with fully feathered tarsi had scatteredfeathers on their tarsi (Fig. lb, c), and, lessfrequently, feathers on their toes (Fig. ld). their toes. Thus, 54 of 119 birds (45%) in some way de- viated from the feathered tarsi-bare toes condition. Of Because of the variety of leg feathering that we ob- servedduring our first two expeditions,in 1997 and 1998 this 54, 16 (13% of 119) had scattered feathers on either we examined 131 nests scattered across eastern and cen- tarsi or toes. Observation of an occasionalaberrant spec- tral Mongolia and report here the tarsalcondition of 119 imen in a population is not surprising,but for 13% of nestlingsfrom 59 broodswhere young were at least 2 wk the population to exhibit such a conspicuousaberrancy of age (i.e., we excluded younger nestlingsto minimize (i.e., scattered feathers in otherwise scaled areas) strong- confusion over ontogenic changes). Because develop- lysuggests allelic segregation beyond what would be ex- mental photos are unavailable for Upland pected without hybridization.Further, 42% of the yourig which Zhang (1984) claimsfledge at 7 wk, we estimated had significantlyexposed (i.e., scaled) tarsi, even though

323 324 SHORT COMMUNICATIONS VOL. 33, NO. 4

A

Figure la. Recentlyfledged, dark morph, Upland Buzzardfrom central Mongolia.This bird showssmall pale breast patch suggestiveof Long-leggedBuzzard dark morph birds but fully feathered tarsuslike about half of the Upland Buzzardsin our sample. This bird is a brood mate of the fledgling in Fig. lc. Figure lb. Tarsi of Upland Buzzard nestlingsin eastern Mongolia. Upper, half-feathered tarsuswith a disjunct line or patch of feathers. Lower, three- DECEMBER 1999 SHORT COMMUNICATIONS 325 tarsal feathering has obviousadaptive advantagesin cold markable similarity between many light morph Rough- climates. legged and Upland Buzzards.Further, many dark morph The variability that we sawin tarsal feathering in the Upland and Long-leggedBuzzards have a unique light Upland Buzzard in Mongolia rivals the variability crescent on an otherwise dark breast and both sometimes achievedafter many generationsof selectivebreeding in have a light patch on the crown and forehead (Brown domestic varieties of (Gallus domesticus)and and Amadon 1968, Plate 107; Fig. la, c). Rock Doves (Columbalivia). Poultry breeders have con- The •nost likely explanation of this tarsal and foot cluded that one or two independent autosomalgenes are feathering anomalyand theseplumage similaritiesis that responsiblefor shank feathering in several breeds of extensivehybridization is ongoing between Upland and chickens.The interaction of these genes produces the Long-leggedBuzzards. Alternately, the Upland Buzzard different patterns and the extent of feathering noted in may be the result of a major hybridizationevent between various breeds (Hutt 1949). Three classesof leg feath- Long-legged and Rough-leggedBuzzards in the recent ering are recognized in pigeons,with the "grouse pat- past. If either (or both) of thesepossibilities is (are) true, tern" more closelyresembling the condition observedin we expect that careful morphological comparisons for feather-leggedraptors. The mechanismfor inheritance other anatomical features of Upland Buzzard specimens of this trait is not clear, but the gene appearsto be au- will also show extreme variability.Another, but we think tosomal (Levi 1986). It is not uncommon in both poultry unlikely, explanation is that the variability that we noted and pigeons for clean4eggedbirds to grow a few short is simply the norm for the Upland Buzzard. feathers on the tarsi or show pin feathers on the toes. In explaining this anomaly, it may be helpful to ex- Levi (1986) found that a strain of clean-leggedpigeons amine Rough-leggedBuzzard nestlingsaround the Sea continued to throw some pin feathers after 35 yr of se- of Okhotsk and Long-leggedBuzzard nestlingsin north- lection againstfeathered legs.Apparently more than one western and eastern , or other zones of autosomalgene is responsiblefor thesescattered feathers sympatrywith the Upland Buzzard.Field teamsworking and the alleles responsible may be recessive. outside of Mongolia could provide useful comparative The geneticsof tarsalfeathering in raptorsis unknown, data on other Upland Buzzard populations as well. In nor do we know of any publicationindicating that there 1997, we gatheredblood samplesfor geneticanalysis in •s any considerablevariation for the trait within either the expectation that comparison of DNA for the three feather-leggedor bare-tarsispecies. The extreme varia- ""will ultimately resolvethis interestingquestion. tion observedin Mongolian Upland Buzzardsis believed to be unique. It is germane that some authors treat the RESUMEN.--Casila mitad de 119 pichonesde Buteohem•- Upland Buzzard as conspecificwith the Long-leggedBuz- lasiusobservados en Mongolia, mostraron tarsosy garras zard (B. rufinus,Vaurie 1961), a specieswith bare tarsi emplumadas en forma distinta a lo esperado (tarsos,em- (Brown and Annadon 1968, Weick 1980). It is pertinent plumados, garras desnudas).Muchos mostraron parches that the only bare-legged Upland Buzzard we noted on de plumas en •reas desnudasde tarsosy garras. Este ex- any of our expeditionswas in westernMongolia and with- traordinario grado de variabilidad puede ser explicado •n Vaurie's (1961) zone of Upland and Long-leggedBuz- como el resultado de una extensivay reciente hibrida- zard sympatry.Also pertinent to the hybridizationques- ci6n entre Buteorufinus y Buteolagopus y/o entre Buteo Uon is Vaurie's (1961) map showingthat the easternmost rufinusy Buteohemilasius. extension of the breeding range of the Upland Buzzard [Traducci6n de Cfisar M/trquez] •s only 600 km west of and at the same latitude as the ACKNOWLEDGMENTS southern extension of the range of the Rough-legged Buzzard (B. lagopus),a specieswith consistentlyfeathered We thank George Gee, Michael Wink, Ted Swem and tarsi. Galushin (1981) mentions a nesting record of the Clayton White for useful comments on the manuscript. Fundsfor our travelsin 1997 were providedby Mr. How- Upland Buzzard on the Amur River that is even further ell Wynne and an anonymousdonor. Our 1994 and 1995 east than the eastern limit mapped by Vaurie. Further, expeditionswere largely funded by USGS PatuxentWild- Vaurie showsthat Rough-leggedBuzzards occasionally life Research Center and NASA-Goddard Space Flight breed only about 700 km north of the westernrange of Center with supplementalfunding by the National Avian both Upland and Long-legged Buzzards.There is re- Research Centre of the United Arab Emirates.

fourths feathered tarsus.Figure lc. Fledgling, dark morph Upland Buzzard (brood mate of the bird in Fig. la) w•th extensivepale patches on breast and head like that known for the dark morph of the Long-leggedBuzzard. The tarsusis half feathered with a more distal, disjunct patch of feathers. Figure ld. Tarsi of nestling Upland Buzzards •n eastern Mongolia. Both birds will have fully feathered tarsi (when hard-penned) and both have a scatteringof feathers on the toes. 326 SHORT COMMUNICATIONS VOL. 33, No. 4

LITERATURE CITED nestling Red-tailed Hawks. USDI/BLM Snake River Birds of Prey Project, Boise, ID U.S.A. BROWN,L. ANDD. AMADON.1968. ,hawks and fal- V^UmE,C. 1961. Systematicnotes on Palearcticbirds. No cons of the world. Vol. 2. McGraw-Hill, New York, NY 47. : the Buteo.Am. Mus. Novit. U.S.A. 2042:1-13. GALUSHIN,V.M. 1981. Changes in population statusand WEICK,F. 1980. Birds of prey of the world. Verlag Paul nest range distribution of Falconiforms in the USSR Parey,Hamburg and Berlin, Germany. since 1950. RaptorRes. 15:4-11. ZHANG,X. 1984. Measurementsof growth, development HUTT, F.B. 1949. Genetics of the fowl. McGraw-Hill, New and daily energy intake of Upland Buzzard nestlings. York, NY U.S.A. [In Chinesewith English summary.] Zool.Res. 5:369- LExq,W.M. 1986. The pigeon. Levi Publishing Co., Inc., 376. Sumpter, SC U.S.A. MOmTSCH,M.Q. 1983. Photographic guide for aging Received17 May 1998; accepted26June 1999

j. RaptorRes. 33 (4) :326-328 ¸ 1999 The Raptor ResearchFoundation, Inc.

CLOSE INBREEDING IN PEREGRINE FALCONS IN MIDWESTERN UNITED STATES

HARRISON B. TORDOFF BellMuseum of Natural Historyand Dept. ofEcolo•, Evolutionand Behavior,1987 UpperBuford Circle, Universityof Minnesota,St. Paul MN 55108 U.S.A

PATRtCK T. REmG The RaptorCentg 1920 P•tchAve., Universityof Minnesota,St. Paul MN 55108 U.S.A.

KEYWORDS: PeregrineFalcon; Falco peregrinus; closein- malesbegin at one year of age. First-yearsurvival is prob- breeding;midwestern United States ably closeto 40% and annual survivalof adultsis 86%. Dispersal from hack or natal sites has huge variation Selection against inbreeding is usually assumedto be (range 0->1500 km for both sexes,but mean dispersal an important factor in the evolution of dispersalpatterns of females (323 kin) is about twice that of males (176 •n (Thornhill 1993), because close inbreeding k•n). •ncreasesthe probability of expressionof deleterious re- Peregrines released in the restoration effort have cessivegenes. We have identified several casesof close passed through three bottlenecks, each of which must •nbreeding (here defined as mating between siblings, have reduced genetic variation in the population. The half-siblingsor parents and offspring) in Peregrine Fal- first was the pesticide-inducedreduction in size of wild cons (Falcoperegrinus) in the midwesternUnited States. populations from which captive birds were drawn. Sec- Th•s paper discussesthe possiblecauses and consequenc- ond, captive-breeding peregrines represented a small es of these inbreeding events. smnpleof the wild populationsfrom which theywere tak- The current midwestern peregrine population origi- en. The number of true founders (unrelated ancestors nated from 857 captive-bredfalcons released since 1982 brought in t?om the wild for captive breeding) for the as a part of the continent-wideeffbrt to reestablishpop- new midwesternpopulation was 70-80 individuals.Third, ulationsof the speciesin areaswhere they had been elim- a founder's contribution of genetic material to the wild inated or reduced by poisoningby DDT and related com- population is determined by differential reproductionin pounds. Midwest as here used includes Minnesota, captivity,which is probablymore pronouncedthan in the W•sconsin, Michigan, Nebraska, Iowa, Illinois, Indiana, wild. Ohio, Kansas,Missouri, Kentucky, sontheastern Manitoba Only about one-fourth of fledged young, released or and the Lake Superior basin of Ontario. We have already wild-produced, actually become breeders in the wild. shownfor this new population(Tordoff and Redig 1997), Through 1996, 1383 peregrines were known to have numbering99 territorial pairsin 1998, that: 72% neston fledged in the Midwest (757 hacked, 626 wild); through man-made structuresand 28% on cliffs. First breeding is 1998, about 290 (21%) of these were known to have be- usually at age two, although some females and fewer come breeders, although some additional birds fledged