Great Basin Naturalist

Volume 58 Number 3 Article 10

7-1-1998

Observations of Black-billed Magpies (Pica pica) grooming feral horses (Equus caballus)

Michael C. Ashley University of Nevada, Reno

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Recommended Citation Ashley, Michael C. (1998) "Observations of Black-billed Magpies (Pica pica) grooming feral horses (Equus caballus)," Great Basin Naturalist: Vol. 58 : No. 3 , Article 10. Available at: https://scholarsarchive.byu.edu/gbn/vol58/iss3/10

This Note is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Great B.mn Natumlist58(3), C 1998, pp. 289-291

OBSERVATIONS OF BLACK-BILLED MAGPIES (PICA PICA) GROOMING FERAL HORSES (EQUUS CABALLUS)

Michael C. Ashley!

Key words: Black-billed Magpies, Pica pica,feralltcrses. gmoming hoims.

On 4 March 1995 I was observing feral and piek for approximately 3 min. During tbe horses (Equus caballus) in the southeast sec­ grooming bout this magpie climbed into the tion of the Granite Range in Nevada (latitude mane of the horse, again withollt any adverse 40°47'19" North, longitude 119°18'13" West) response. The wind was variable, 10-15 kph, (Fig. I), when 1 witnessed an interaction be­ and stronger gusts occasionally caused the 2nd tween a Black-Billed Magpie (Pica pica) and 2 magpie to struggle. . to maintain its fnoting.. In of my study animals. The magpie alighted on one instance the horse twitched, dislodging the back of the 1st horse and moved around the magpie. the animal's back. The magpie appeared to be I nexl observed 2 magpies grooming a year­ scanning each new section of the horse's hack ling feral horse on 12 Aprd 1997 in the Gran­ a') it moved, oc>casionally making pecking move­ ite Basin, approximately 7 kID south-southwest ments with its head, presumably removing of the previous 2 sightin~s. This encounter ectoparasites from the animal. After about 3 lasted sligbtly more than 10 min. One of the min, the magpie left the 1st horse aud landed magpies groomed the horse's rump, hack, and on the back of the 2nd animal. 11 repeated its dorsal area of its neck up to the base of its searching and picking behavior, this time mov­ skull. The 2nd magpie clung to and groomed ing onto the horse's neck and searching exten­ the ventral surface of tbe animal's neck for sively through its mane. After 5 min on the more than 1 min, moved to the inner aspect of 2nd horse, the magpie returned to the 1st and the right foreleg at the hock for 4 min, and searched its mane for more than 1 min. Nei­ then briefly returned to grooming the under­ ther borse attempted to displace the magpie side of the borse's neck. Although there were and both remained quiet throughout the visi­ periods when one or the other ofthe birds was tations, suggesting familiarity with this behav­ not on thc horse, there were 2 magpies ior. 1 was able to closely observe the magpie grooming the animal simultaneously for more behavior with a Kawa 22-60X spotting scope than 5 mill. from ~20 rn. The regularity and extent ofthis behavior is On 17 February 1996 1 saw a repeat of this impossible to determine at this time. In more behavior with 2 magpies and 2 different feral than 50 trips to this area, I have witnessed horses. This episode occurred approximately 2 only these 3 incidents involving magpies and km east-southeast of the lst ohservation hut leral borses. The distances between observa­ within the same valley. A magpie landed on tions at the Granite Ranch sile and between top of the withers of tbe 1st horse and moved Gnmite Ranch and Granite Basin can lead one about its back for 3 min, occasionally picking to believe that magpies in this area search for at the horse's back. horses to groom rather than wait at an estah­ During the same period a 2nd magpie flew lished feeding station as described by Isenhart to a nearby sagebrush (Ar/.emisia triden/.a/.a) and DeSante (1985) f<>r Scrub Jays (Aphelo­ and appeared to be watching the bebavior of coma coerulescens) cleaning Columbian hlack­ tbe 1st bird. Tbe 2nd magpie then flew to the tailed deer (Odocoikus hemionus colurnbianus). back of a 2nd horse and proceeded to search That ~onclusion, however, ccmnot be supported

1Biology OeparlIll(l.l1t, Uniw..nily of N<;WI\d.J., Reno, NV t!9557.

289 290 GREAT BASIN NATURALIST [Volume 58

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Fig. 1. Locations ofgrooming events: (1) Granite Ranl:h, 4 March 1995; (2) Granite Ranch, 17 February 199G; (3) Granite Basin, 12 April 1997. Enlarged ii'om u.s. Geological Survey 1:100,000 Gerlach, N\~ map.

by the small number of observations and lack Magpies are reputed to probe sores on the ofindividual identification ofthe birds involved, backs of domestic and wild animals that are in On 3 occasions I have seen magpies in the poor physical condition (Bendire 1895). All of vicinity of feral horses in even more remote the horses 1 observed beiug groomed by mag­ sites in the Granite Range; however, I saw no pies were in excellent condition. Because I grooming. viewed the behaviors closely, from <20 m with Magpies exhibit a variety of opportunistic a 22-60X spotting scope, 1 am confident tbat foraging practices including scavenging, prey­ grooming took place. I suspect the magpies ing on nests (Groom 1993, Pampush and were removing ectoparasites from the animals, Anthony 1993), preying on small mammals not probing sores. Ticks (Parasitiformes: Meta­ (Goulden 1975), and grooming large herbi­ stigmata) are ahundant mammalian ectopara­ vores (Dixon 1944, Linsdale 1946, Linsdale sites in the Granite Range and are likely objects and Tomich 1953, Massei and Genov 1995). ofthe magpies' behaviors. 1998] NOTES 291

These observations add to the number of BE:-JDIRE, C.H. 1895. Life histories of North American apparently mutualistic interactions between birds. Smithsonian Institution, Washington, DC. DIXON, lG. 1944. California Scrub Jay pich tich from corvids and large herbivores. This extensive mule deer. Condor 46:204. relationship includes (1) Black-billed Magpies FITZPATRICK, C.W, AND G.E. WOOLFE:-Aphelocoma califomiea) GOULDEI\", L.L. 1975. Magpie kills ground squirrel. Auk 92,606. (Dixon 1944) interacting with mule deer (Gdo­ GROO~1, D.W 1993. Magpie Pica pica predation on Black­ coileus hemionus); (2) Black-billed Magpies bird Tu.rdus merula nests in urban areas. Bird Study (Linsdale 1946) with elk (Cerous canadensis); 40$~62. (3) Florida Scrub Jays !/J.phelocoma coerules­ ISENHART, FR., AND D.F. DESAI\"TE. 1985. Observations of Scrub Jays cleaning ectoparasites from black-tailed cens) with white-tailed deer (Gdoeoileus vir­ deer. Condor 87:145-147. ginianus) (Fitzpatrick and Woolfenden 1996); KILHAM, L. 1982. Cleaning/feeding symbioses ofCommon (4) Scrub Jays (Aphelocoma coerulescens) with Crows with cattle and feral hogs. Journal of Field Columbian black-tailed deer (Gdocoileus hemi­ Ornithology 53:275-276. onus columbianus) (Isenhart and DeSante LINSDALE, J.M. 1946. American Magpie (Pica pica). Pages 133~154 in A.C. Bent, editor, Life histories of North 1985); (5) Common Crows (Corvus brachy­ American jays, crows, and titmice. u.s. National rhynchos) with cattle (Bos taurus) (Kilham Museum Bulletin 19l. 1982); and (6) Common Crows (Corvus brachy­ LINSDALE, J.M., AND P.Q. TOMICH. 1953. A herd of mule rhynchos) (Kilham 1982), Florida Scrub Jays deer. University ofCalifornia Press, Berkeley. MASSEl, G., AND P GENOV. 1995. Observations of Blnck­ (Aphelocoma coerulescens) (Baber and Morris billed Magpies (Pica pica) and Carrion Crow (Corvus 1980), Black-billed Magpies, and Carrion carone cornix) grooming wild boar (Sus 8crofa). Jour­ Crows (Corvus carone comix) with feral hogs nal of Zoology London 236:338-341. (Sus serofa) (Massei and Genov 1995). PAMPUSH, G.J., AND R.G. ANTHONY. 1993. Nest success, habitat utilization, and nest-site selection of Long­ billed Curlews in the Columbia Basin, Oregon. Con­ My thanks to E. Gray and S.H. Jenkins for do,95,957-967. review and comments, and to the Bureau of Land Management for supporting my feral Received 18 June 1997 horse research. Accepted 27 September 1997

LITERATURE CITED

BABER, D.W, AND lG. MORRIS. 1980. Florida Scrub Jays foraging from feral hogs. Auk 97:202.