SOARING BIRDSOF MT. EVEREST by Edward E. Hindman, New York City, USA Irresented ai the XXll OSTIV Congress, Uvalde, Texas, USA (1991) and rcvised 1992.

the birds first hand. MoLurtaineerint literature This paper contains .lc' on the Mt. Everest retjon of scriptions of soaring bircls fie Himalaya oI obscrved n the Everest re and occasion- gion and estxlates of the allycontainsobsenationsof choughs Blidnrg chara.ter- so;rins brrLls ULLmrn(lob4l istics. It is shown ih.l thc repnrtid srghtrngc of the birds most likely sodre.l tl) ih k\a,r rd blaLl "Borrk" the cxirene aliituclcs in tlrc bird sc.rverlsrnA .ri R.1se nirflows causc.l by lverest. Camp (17,800 fcetelevatht, Thc choughs appear to be 5400n) on thc gla- the surrogate soanng "pi cier and at advanced based crmp (21,100 feet 0450mlrn 2. Sightings of soaringbirds nerrhr Wesr awrn F,,r ilrer,'h, Vcnables (1989) Rflt'.'|1(Carcus corrx) repoted sighting brjlliant The most recorded bhck cl1oughs high-altihdc sightinSs have oc.urrcd at scavengefs "dancint in the tJase Camp (17,600 feet, \^'lnd" just belorv the South 5330nt on the KhurnbLr gla Cc,1 on fi e Kansshuns (easi) cier(Fisure 1).Ullman(i961) face E! erest at an elelation refers to the au'kwarcl, poor of26,000 fect (7eil0nt. Also, flyhg, black gorak (".ror\" Welt)' ( 1975) rcportcd h Nepali). I'orzak (1991, choughs have bccn sccn at pcrsonal conmunicaiion) 27,155 feet (8230m) on the rcports sccnlg thc goraks sunrmit pyramid of Everest. soarand "jurnp" from thcr Ho$'did the birds .iclieve Iigurc 1. a. Thc Evercst-l.hot!.rNuptsc trirriir v;r$ e.l mnl tothermal in the!icinity these .rltitudes? To help .rn from the rvesi. thc locations ofbird sightints at Bnse of BaseCampduring hissuc swer thjs question/ the Clamp, Wcst Cwm, l.hotse fac(: ard .1rt cessful chnb of I]vcrest in lrutlror climbcd from the indicatecl. the spring of 1'190. Uchi.]a Lukln ajrstrip (9,100 fcet, b. \4i. Everest and the Kangshung frce \'ie 'cd lron (1r)rr1) reports Corikshep 2760nt toKala Pauar(18,320 the noriheast. The piciures sho$ thc mod,n .f l\'1r (l7,500 feet, 5300m) the feet, 5550m) near the base of Everest rvlrich was locakrd in thc Eoston Mrsernl of Sherpa sum]nervillate near Mt. Everest in Novembcr Science, Sulrlmer Lss0.The m o.1cl rv as p ro.tucc.t front cst Basc Canp, mcans December, 1992 to obscne the mnp of Mt. Evercst by Washburn (1988). "gravcyard of crows." Ap

TECHNICAL SOARING pareni]y/ihe8orakcannoiW usiinindsingeL(196]) ]]iriI];li:]:.:lil'i.:'|lWl"$#N"$l:tii['ltiili]lii:i.*.iji|lT: il:li:5,::*1';,'.1ilr :::it:li iii'ilti:':,fi ,r,\.,r,u,,.r,'.ur\,!prL,., lffi n,.r'n.pcrrrr,.,.rr.r,ougir. likc ih. climbcrs. lMllfilliN\\\N#"i7,Z4iiriii!.IFr5lffi'l " -jiiryfl nrdividuallv anLl in noaks have occlrrre.l in the West l.i\:,t>t) 41!t:l!t",!ry!itti1--Fi/tlilit-::l i:volutions aro nd rl; ir c\\'n, (sec liBure 1).Por'"k l:l:,i_!.:4'lfl!.f:i-i:-H:f.l *G.' r::l cliffs, wheelins and dash ;:*i:':il:ii,"iir.li:lW-lreili,ffi'#t#,tLi1ilEi:i::tifi lt;iilili:x Hfi :,ix:l:li,'J'.lii: lal1rr :lt:r:;::i:ll:exx;saurts'alrsee''ngrvrordre li,Lt1*.|E':'ilr.1"5 \i.liffil-ill*iilffitill .,:,:i,;..t. 7820m). This obse,aatiot\is l:'tlDr.:!):a::!t r;].'=':' ::=-, :i.:l Theaufor obscn ed sjmi

h:ri!:ll:"':l-:5:llll.l,i''llWlil|ilil";:l.l:lIl.ili'''r'" riililTLlrf; cwm (21,3s{) il:niJt-.TI;:i:Ji:i i:$r lwlffi i;,,:,li ilStltrfjl:i}"" l . .,,,'l,n nl1.pr\,.1 ph,,r,,,,t r br ed cl.rBhs at hish elevatjon ),11,,. ro,,r r s J r,r rr r,)!J rirn\ n r,lls fiql': ltA:l"b"l* "tplnc iho"gt. pc.ihea on a rock ii,. r,.t ro,.- 11r,. bi.J: JrJLrdr,l,',.11-.,r'or, Il,epl oroqr-p|,.,^nrl,. .,r rt;c irrrnrrrr oi Krrr h(r(L,bn.nrd lobce^-el ,r' r, f.r, rrrl.r.snr|,R loollrornr.rurl-l li.rr& t.JtrJr ()rrrn rhr.v .,n- video,108 i Rd., Dccrfjcld,ll- lent scavengeF but poor a r Wilmo 60015. p,..i".i t" l1 r,t" soaring. They could not cross country sailplane"rf".iii" pi- perform symmetric hrrns hsoarhg flight,blrt fre(tuently lots. llecause of their hith specd glides and cxtrem€ flappedand adjusted their\rjngs whilc circling, unlike maneuverabllitv, rhey arl the Na;chc Bazar "fighrer the Lammergeicr (scc bclow)which appeared to lock its pilois." wnr8s irtd circle likc a sailplane. Stcp...l cn.Lc Art ilnniptiusis) \tLt'Slt t!t'|o,,',r ll.nrr,g.er,l lloTaj-ppurl,Jrlpppcr.rgl'w.,.r.,rrrd Tl,."eL'i'd.lu\, b,rr-r8l l.dortl,eKir,E.l,u t,..,.l dF- lurrl! \.rrrlri,,l irilo,,c. |r, b.o rihrnwrrrJ facc)(sccFignre 1)r the rnos t recent face of Everest to be hcnce, could not be {onfused wjth the black goraks or climbed. Venables (1989) repo.ts sccnl8 the chough choughs. "dancingh the rvind " just belor{ thc SouthCol on ihc Ini kr8.ict(Cypnrt sbatbntr.) Kangshung fncc ar abour 26,000 feet,7900n (se€ t igure BoihIilcming, etal. nnL1 FisheranLl Pctersoll reportihe 2). lhis reportcaught theauthor'sattentionbecause ihe Linrmcrsrier (beatulccl vulture) beins in the vicinity of birds were Rying in the turbulent wakc of thc Evc.cst Everest a t 21,000 feet (7270m), the bird is brown a dllas pvram , an uncxpcctcd locatjon for sonrtng flight or .r sp.rrrofup to9 fcct, so j i cannoi bc confliscd lvith thc any type of flight. Borik and choughs. rheThe chouthchouehchough has been characterizcd ij the litcrniurc. Thcauthor made numerous sightmgs ofbrowr soar tlening,eial. ( 1979) luvc d escribeddthefljghtchnracter the rng bjrds, most likely either the Lammergcier or thc jstics of the red-billcd chough as vcry playfLr) ancl SteppeeaSle. Ai 1030LSTon December4, r pairoflarBe, cavortmtilrt]re air. A fnvorihr gan1e thcy obscn cd near b(nrnbrorrn birclsbir.ls were seen to.onia.ito contact a thermaldjrectlvthermal dire.llv of1off Dhaulagirjrl,.rs foracltougl, tcidcscen.i a narrorv gully therne endeno ofor therne rya'lgoocneSyangboche rrrstnpairstripa'rsrnp rndandarlo cljnbclrrrbcn'nD slix]vslowls,ow'y sl(x!ly, supporied bl' a strong updratt. Once at the (€stimated 200 ftlmin)ft /min) circlinrcirclnrg oppositeoDDosi te each odrer witwith bottom, the bir.l extcndcdo ir ts s,nrgssnnSs and ascendedascenoed qu ickl], locked w ings jL rst like two d isci pllned gijd er pjlots. The and.rnd waitedh irtLd inrn turn for{or the nexibirdl1e\ib,rd tocompletetoLDmplete thecvclethec]'cle'cK,y birds app€nred not to "iop" iltc thermal but rolle.t oft (it s r\ nut mcn lioned whethcr the \v r trngbir.l perched flexed their l{'ings nnd rapidly glid€d (penetrate.t) up ihe Dudh Kosivallev tolrard . Lik('wise, theauthorobsen ed ontheclearmorningof from this sumrnnr!,, it appears the goraks, chouths, Novcmber23, 1992 ai0950LSTa gaggleconianingover Lam ergeier .rnd Steppc ergle nre ihe lo1\'nltitudc 100 . LoUBl . .p.r.,linB i L, il,.r 1,Jl ,h,,\ c tlr' -lu p., F.vcrcst flycrsand ihe choughs the high-altitude fli'€rs. '.llJg. .l Drn,tb^.1r. (l .rol f.,i l'7lmJ ll,, '1.,.1 Irurihe,, thc goraks ind choughs appear k)be ihe ntost driftad k warLl the f;rce of Phok.r ].:le (19,160|eei,5805m) frequen t fl iers of rverest. Venables ( 1991, persona I conr- nr the Lrpslopc flow. municatjon) sLrpports th js conclusjon. risherand I'ctcl'son (1977) state, wjihout supporinrg 3. Bird aerodynamics evidence, that ihe alpine ck,uglr has probably rcachcd Thr updr.ft strcngih rcquircd for thcchougl$ to soar thcsumnitof Ilvcrest. hr all the literature theauthorhas and, thus, perform their aerial aerobatjcs can bc esti re.ld on Everest, no discLrssnrn of tltc 5umntithns men' m.ied fron thc minimum snlkin,l specd (Vn.) of the tioned the appeararrcc of the bird. it is important to bird. The Vn15 value is obtajned from ihe bird gljde- document h'hether r bird has elarrbc.r sighte.l on ihe polar: sinkfig speccl (v2) vcrsus nrsard specd (v). sum,i'ir ihe reports by lvelt)' (1q75) of chouths at PennycLl irk ( 1989 ) p rovides th€ iecessa ri a lgorithn to 8230m on l-v€rest nrdic.rte thc birds ltrre bcen sighted caiculate bid glnte-polars: near the summitwhich ls.rt.n elelition of8870m. Vz , DV,/mg (1)

VOLUME XVIII, NO. 1 rcst,lts in an nsp.:ct riti() 6..1 inal w,ng l..rJrng of 21.8 N/ mz (1).12 lg \ 9.8lrr/rrl 0.t.l,1mlt ill r.isolrhl,. !.,1-

Theabove m.rss,ivingsp.n ar)ct wnrg aren for the rcd billed.houBhw-creLlscd with (l) lo cnl.ulite th. sl'J, polnr rt

TECHNICAL SOARING 5. Conclusions Thc highcst flvifg blrd on Mt. [\'ercsi appcarsiobe ihe chc,l,gh, whlch has bccn ob- serYed "dancing jnthel{'in.t (eiiher so.rring or pcrn)rm ing aerobatics for thc obsc^'hs climbcrs) just be los ihe south Col at nbout 26,000 fe$ and on the srlm mit pyramid at 27,155 fect. The glide polar of thc red- billed chough was cstnlated. It was found th.r t ttris bird may havc one of the 1o$' est snrkmg specds of an) soarint bircl; a possibleex- planation for the supcrior aerobniic artd soarhS skills

Thebird sighthgsoccurcd jnregicmsof kno$,nrishgair around Evcrest support ih€ corlclusion th.rt ihe choughs soarcd io th(' rcmarkable i2!,02B N heights. The birds are.rs' su re.i not tobc nblc b flv k) thesc hciShts u1.tcr thcir ;r1r Pos,cr/ an assumPiion rcqurr 1 lllg s!pPorting obsefvatiotrs

Other questbns ren.rnr k) be ansrvered. Why do the choughs flv sohith? Arethey curious about tlte brightly clrd chnbers, arc they beg- glng f<,r nx,d or do thcy fly Figure 4. schcmatic of the Everesi irinity nnd the air flows just because the ljft is ihere? deducedbyHindm.1^(1986), HinLlmrn ind Wjck (1990 a,b)and cloucl obscrvations .Also, snlcc 1952 m any c limb- maclc by thc aL,thor dLtring November December, 1992 (I Iin.:tman, 1993). ers have renched the Everesi summit bv ail but the N! ridte rouie. To the author's Ii is temptnrg b postuhtc that choui{hs could soar in knorvlcdgc, no bird sightings have becn r('portcd fronr ihe risnrg air nr thc wakc of tllc Evcrcst tyranrid, this the summjt. It rna,v be rmpossible for the chouths to risnrg air (when moisi) forms the banner cloud. If this rsccnd to th.r sunnnit or a sailplinc, for that matter. posiulatc turns out b bc trlre, thc up drauitlrt nrust bc Nevertheless, othcr fljght acti!ities have taken place greater ihan thc 0.66 m/s nrinimunr sink spccd of thc ii lhe Lverest sumDrit. A piraglider descdrt from thc choughs aialtiiude (see F iture .l). lroriher, thc Lrir must sutnmit was planned b!rt noi execuied due to an nrabil' be turbule t it1 the lcc of [\'crcst but thc turblrlencc ity of th. pilot io.limb to thc summit (llowlh8, 1991). rvorild have to be sufficientl,v coherent lor the choughs However, a successful paragl erdescent from the sum' to move from one risnlgcd.t) h) anothcr and avoicl thc mlt $/as reporied by Wilcox (1992, personal sinking ed.lies. .ommuni.ain,1) and b) Touranch{,au (19e2, personil It is assLrne.l thc birds.anrot fl) k) ihcs( altitlr.lcs .ommu,ricat](nr); p.rr,rgl er flights on Elerest's lowrr un.lcr thcir own porvc' thc.alclrl.tions to !erift this slL,pcs hrvc bccn rcportcd by Schcllhannncr (1q92) crLLcial assumption llave yet to b. perfonned; lrerxrvcuick liin.nl'', hot rir brllo(n$ ha\ c fl)wn ovcr the summit as (1989) mi), prcvidc thc colnpl,iatiuul fram$vork. rqn,lcd by 1)ickinson (l992), thc flights wcrc r€ported merefore, the birds had io soar i(r reach the extre re tobe"ihe ultim.rteascent."Theultin]ate.rscentreDranls altitudes. TIlis cr,rclusiolr is rcasonible bccause thc L L', t,,t,r,,"1 , lr,rl-1 , ,,.r', Bb,d.r.,,o, ,,- locations of thc bird sightnrSs ir1 thc lvest C]vm and 6. Acknowledgments K.' t. lr..rrqi.., .rr, r'r5i,'r.,'itron i.ir.F.,ir.. ' .l. Flr.rlfel lur,tsllre \.rrfnE.rlts ,.rr.rrgf'l.l . t Prof. Janei NL Willims of S*nrthnrorc Cdleg€, F.vercsL Carcfulobscnationsof thcir fliglris m.ly rcvcal Silarthnrorc, Ircnnsyl! aia proviLled ihe pichrre of thc possible s.1fe r1r tltes to ihe sunnnit nn a skilli'd sailpLxrr acrobatic choughs rn l'igure 2. Raiau Shopa skillfully pilot. guidc,:l tL[.ruthornnd car ricd alrx)stnll ihe geardurnrg

vaLUI'tE XV t. NO. 1 the Nolember Deccmber. 1992 trck k) the balc of Mt. flights." Subn\iticd h) XXtll OSTIV (l('rgress, June, t993. McMashrs, J. H., "Arr an.rl,viic suLvcy of low speect Auslin,O. L.,Ir. and A. Shqer, ADlsoflrr m)rld,(loldcn flynrg devices naturil and m.ri made." T.craxr,l Press, New York, p.226, 1961. Sonrnrg, Vol.3, pp. t7 3(r, 1974. i ts. dnd F.I .tr Ledrto .,.,4nai., "mpbcll. ,r'.,1Ir',/. I'ennycuick, C. 1., Bt'd I llqr/ P.,'/o/,rrr.., Llxford, 118 B.rl'd Bo.'1..\"rnIlli^n.np ./15 22" loSr Pp.,1S8q Dicknlson, V. L., Ballonfntrcn ubta d( r.rttcst. t'errins, C. M. and A. L. A. Middlclon, T/?. [,,]y./.p!iin "1ot"t Gleitschrin. Nov/Dec, i9q2, pp.36 40, 1992. oIBtds, Facts on File Publicatbns, Yo.k, p.-143, fjsher,J. and R. T. Peterson, T/ze WuldrfBirls, Lloublectay ^-(:w and Co., Garden City, N\, p.15,1977. Porzak,Cl.,"Amer'canEvcrcst-LhotscExpedi n,'Trr llemins, Sr, R. L., R. 1.. Fleming,lr. and L. S. Bangder, Explotc/s loutndl,\al. 69, No. 2, pp. 38-,15, 1991. Btds o/ Ncprl, Avalok Publishcrs, Kathmanclu, p. Schellhammer, V. C., Nepal. clleitschim. Nov/l)cc, 358.1979. oo).I,P l4-44 lnaz Dowlhg, C. G., "Too near thc stn," LtJi Magazinc, Uchida, R., Trctk;rg Mout Erdrrsl, Chronicle Llooks,Ian S€ptember.lot'1, pp 47 56. Irancisco, 128 pp., 1991. llrnJn:n Ll.. Arerrdl'E\.4t I \.r. tthr,'[Ehr'J'- U11man,I. R.,,4nrrricrrr o, fi,c/.s/,I. B. Lippnrcoii Co., i\sflisht," Tc(httiol Sanrnls, Vo]. 10, pp.41 52,1986. Ncw York, p.-129, 196'1. I lindman, E. E. and F.. J. wick, "Air moti('$ h the Ven.rbles, S., ft'./.srr K,,r.tsr",8 r'.r, Hodder & vi.n itv ofMt. llver.si as d.d u..:d from I'ila ius l'ortcr Sbughton, Lon.lon, 236 pp., 1989. flightl," Ttthnicnl Soari,S, Vo]. 14, pp. 52 56, 1990. lvashbu r, U., "Mouft ilveresi: SuNe)inil tlre thirLl Hndman, E. E. and E. l. wick, "Air motn)ns h the pole,".l. Ndhr,,n/ Cc,)tmprt. S,./itV, Vol.174, pp.653 vicuriiy ofMt.Iverest as deduced trom aircraft.lncl 659,1988. cloud obserwations," I'rcprints lif th Conference on Weli\', T. C., Thc Lilc al Bihls, w. B. saulclcrs co., Mt. Meieorology, Am. Meteor. Soc., Boston,pp.166 Philadclpia, 623 pp., 1975. 169. 1990b. lVilcox, R., Choughphoio. NrifHa,rpr/r;/. Prc'r.r, Feb Hnrdman,I:,. E., "Airm.nnDs in the Klturnbu Himalayn runry, pg. 2, Portsmouth, NI i, USA, 1991. \.,re,, DFr De.embe, l,o) " rl l, ...b., ",rr.irt

TECHNICAL SOARING