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Home , American avocet, Curlew sandpiper, Pectoral sandpiper

RARE OCCURRENCE

FirstNorthern Hemisphere record and first juvenileplumage description of the Cox's (CMidris pammclanotos)

Mark J. Kasprzyk, Richard A. Forster, idris paramelanotos)was observed and Brian A. Harrington AJUVENILEand photographedCOX'SSANDPIPER in Massachu-(CAL- settsSeptember 15-21, 1987. This spe- cies was first formally describedto sci- ence in 1982 (Parker 1982). Approxi- mately 40 individualshave been seenin the field with only two specimensknown to exist, both of which are adults. All previous records have been from Aus- tralia. Becauseof the infrequencywith which Cox's Sandpiper has been re- ported and the fact that its breeding groundsare unknown, it is possiblethat this form may be a (Marchant et al. 1986) rather than a valid species. While mist-netting shorebirds the night of September15, 1987, staffof the Manomet Observatory caught what initially appearedto be a ( melanotos)at Dux- bury Beach, Plymouth County, Mas- sachusetts.During banding,we noticed that someof the morphologicalfeatures of the sandpiperwere strange:the bill was very long and the breast streaking was not as prominent or sharply de- marcatedas in a PectoralSandpiper, es- pecially where the streaking faded out along the lower median edge of the breast. The bird was aged as a juvenile on the basisof its fresh plumage, par- ticulafiy its unworn tertials. The indi- vidual was banded, measured, photo- graphed, and released during the early morning of September 16. The especiallylong black bill with slightlydrooping tip wasthe mostobvious field characteristic In later reference to literature con- of the Coxg SandpiperDuxbury Beach, Massachusetts, September 16, 1987. Photo/MarkK. cerning Pectoral Sandpiper plumages, Kaspryzk.

Volume 41, Number 5 1359 suchas the long black bill and leg color better fit the description for Cox's Sandpiper. On September19, after further study of the bird at Duxbury Beach,and based on the field characters and measure- mentswe had discussed,Forster became convinced that the bird was a Cox's Sandpiper. On September 19 and 20, several more observersexperienced in shorebird identification studied the bird with us. The extensive white sides of the rump, uncharacteristic of Sharp- tailed Sandpiper, were well-seenwhile the bird preened; the extensive white uppertail coverts contained a few streaksthat ran parallel along the dark central tail band, unlike the unmarked uppertailcoverts of PectoralSandpiper. The uniform ageof the body feathering and the light edgings of most dorsal body feathering characterizedthe bird asa juvenile. We ultimately agreedthat the long, entirely black bill, the pro- portionatelylong olive legsand the ex- tensively white uppertail coverts with light streaking most closely matched those characters describing a Cox's Note thefine breaststreaking against the buffybackground. Streaking is bolderon the sides Sandpiper. of theupper breast and absent Jkom the roedial portion of thelower breast. Buffy background On Monday. September 21, staff at colorationof the breastis not sharplydelimited from the white of the belly.Note the split Manomet Bird Observatorymet to dis- supercilium,with the upperbranches less prominent than the lower.Duxbury Beach, Massa- cuss how to proceed with the Cox's chusetts,September 16, 1987. Photo/Mark Kaspryzk_ Sandpiper.Scientifically, a strongcase we found many important contraststo the fine streaks faded near the lower existedfor collectingthe bird. Not only the characters we had seen. Adult Pec- central edge of the breast, unlike the did this individual representwhat was torals are boldly patterned on the chest, stronglypatterned, sharplydemarcated apparently the first known example of and juveniles, although less promi- streakingof a Pectoral Sandpiper. By a juvenile Cox's Sandpiper and a first nently marked than adults, still possess default, the bird was then identified as record for the northern hemisphere,but a complete, well demarcated pectoral an adult Sharp-tailed Sandpiper that a preserved specimen would provide band. Therefore, we consideredSharp- possesseda plumage unfamiliar to us. various characters that could be used to tailed Sandpiper (C. acuminata) to be We were confidentthat it was not a ju- study the bird's taxonomic status. the most likely alternative identifica- venile of this species.The Massachusetts However, another option was to usethe tion, althoughthe bird possessedexten- Audubon Society rare bird alert was techniqueofmitochondrial DNA anal- sive streakingon the upper breast and notified of the bird with its new iden- ysis based on blood samples to deter- lacked the orangishcolor on the upper tification that afternoon. mine the relationship of Cox's Sand- breast and crown characteristicof ju- Later that night, we discussedour piper to other species.Such a blood venile C. acuminata. misgivingsabout the bird's identifica- sampleis best obtained from a live bircL Remaining unconvinced, Kasprzyk tion as an adult Sharp-tailedSandpiper This procedurealso alleviated our con- returned to Duxbury Beach on the eve- and consideredthe possibilityof a Cox's cern about collectingwhat might be an ning of September 17 and recorded a Sandpiper (Calidris paramelanotos). exceptionally rare specieswhose distri- complete field description of the bird. Comparison of the in-hand measure- bution and total population size are On September 18 it was studied by ments were made against measure- unknown. We therefore decided to at- many observers,including the authors, ments for Sharp-tailed, Pectoral and tempt to recapture the bird. as it foragedin the wrack with Short- Cox's sandpipersgiven lzy Marchant et Rocket-nets were set up at the high billed (Limnodromus gris- al. (1986). The bill length was well tide line of Duxbury BeachSeptember eus), White-rumped (C. within the appropriaterange for Cox's 21--23 in an effort to recapture the fuscicollis)and SemipalmatedSandpi- Sandpiper;further, it was 3 millimeters bird. However, we did not see the bird pers (C. pusilia). The bill was long, longer than the maximum bill length after the morning of September21. Af- rather fine, and decurved; the upper listed for Pectoral Sandpipers, and 7 ter September 21, a noticeable reduc- chest and breast were finely streaked; millimeters longer than that given for tion in shorebirdnumbers and diversity, and the legswere olive, darker than the Sharp-tailed Sandpipers(Marchant et followinga break in the persistentstorm typical yellowish of a Pectoral Sandpi- al. 1986). As we compared the field pattern, indicated that many had per. All observerscommented on how marks, we discovered that characters resumedmigration.

1360 American Birds, Winter 1987 Descriptionof a juvenile Cox's Sandpiper

Measurements taken of the bird in hand are followed by measurementsin parenthesesfrom Marchant et al. (1986) based on two specimensand one live bird, and from Lane et aL (1981) for weightbased on one bird. Note that the wing measurementslisted in Marchant et al. are basedon a flattened wing. wing (unflattened)chord: 129 mm (I 34- 144 mm) culmen(exposed): 35. I mm (33-37 mm) weight: 67.9 g (67 g)

Bill: In the field,appears entirely black: in hand, the base of the lower mandible and the upper mandible immediately anterior to nares is slightlypaler with a grayish-olivetone. Long and thin, slightlydecurved at the tip, slightly longerthan the lengthof the head.Longer and proportionatelyfiner than on eitherSharp-tailed or Pectoralsandpipers; slightly shorter and not as "thick," especiallybasally, as in (C. alpina). Most similar to Sandpiper(C. ferruginea),but lessstrongly decurved, and with a lesspointed tip. Legs: Olive or olive-brown. Proportionately longer-leggedappearance in comparisonwith PectoralSandpiper. Leg color darker than the yellowishleg coloration of PectoralSandpiper, mostclosely resembling that of Sandpiper Here the breastcoloration and streakingare evident,as is the bird• elongatedbill. Duxbury, (C. himantopus). Beach,Massachusetts, September 16, 1987. Photo/Mark K Kaspryzk.

Breast:Incomplete band of fine blackish-brown supercilium faded out, and the conspicuous Tail: A detaileddescription of the rectriceswas streaksrunning vertically acrossa rich buff lower branch extendedslightly upwards, con- not obtained.Photographs of the bird in-hand background,the streaksbeing lighter, finer and tributing to a slightlycapped appearance. indicatesthat the tail wasuniformly dark. Cen- lessclearly demarcatedthan in PectoralSand- tral rectriceswere longer and more pointedthan Wing: Upper wing coverts were light gray- piper. Streaksbecoming less pronounced to- outer feathers,similar to a PectoralSandpiper. ward the lower central region of the breast, brownedged pale buff, lower wing coverts edged which appearsunstreaked in the field; in the rufons.Primaries dark blackish-brown.In flight, Behavior hand,small blackish-brown flecks were present narrow white wing bar formed by pale tips of in this region.Breast patterning lacks the sharp greater secondarycoverts. At rest, primaries cutoff characteristic of Pectoral Sandpiper. extendedjust beyondthe tail. Tertialswere dark The bird foraged in the wrack by blackish-brownbroadly edgedwith bright ru- Streakingextends farther along the upperflanks peckingand probing. While the Cox's than in Pectoral Sandpiper. Breast coloration fous. Sandpiperwas alwaysseen in the com- and patternsomewhat reminiscent of juvenile Scapulars: Lower scapulars with blackish- Baird'sSandpiper (C. bairdii), exceptfor the brown centers;feathers fading to light brown pany of other shorebirds,it never as- greateramount of streakingin the Cox's Sand- at the base.Dark feathershaft streaks extending sociatedwith any particular species,in- piper. through white feather tips; shaft streakses- cludinga groupof three PectoralSand- Undertail covertsand belly: Immaculate white, peciallyobvious on basal,light brown portions pipers that was sporadicallypresent at no markings. of lower scapulars.Upper scapularswith more Duxbury Beach. During its visit, the uniformlydark feathercenters and more com- Head: Chin white; throat mostly white with plete, brighterrufous edgings, without the con- Cox's Sandpiper was seen regularly faint streakingalong lower edge. Lores blackish; trastingwhite feathertips as in the lower scap- along 70 metersof beach,usually from crownwarm brown, finely streakedwith black- ulars. The richly-coloredupper scapularscon- two hours before until two hours after ish, palingat the nape wherestreaks were gray- trasted with the back and lower scapulars, high tide. However, from September somewhat like those on a juvenile White- ish-brown with a lighter brown background. 18-20 it remainedlonger, still foraging Auricular regionrufous brown, accentuatedby rumped Sandpiper. in the upper tidal zone. Only once did palenape. No noticeableeye ring Whitish su- Mantle: Blackish-brown feather centers; feather perciliumobvious but not prominent,with in- we seethe bird feedingaway from the edgingspale buff, givingspangled appearance. distictgray-brown streaks. Facing the bird, the Contrast between brighter, more strongly ru- tidal wrack on sand flats; we could not superciliumappeared to split immediatelyan- fous-edgedscapulars and palermantle feathers. find the bird during low tides.We never terior to the eye, similar to that of a Broad- Pale "V" along the mantle edgesand across heard the bird call. billed Sandpiper(Ltmicola falcinellus). The scapularsless distinct than in Pectoral Sand- upper lessconspicuous branch extended up to In , Cox's Sandpipers have piper due to duller feathertips. the sidesof the crown and then ran parallel to been describedas rapid probersin soft the blackishcrown streaks;the more prominent Rump: Solid blackish-brownband extending mud, often feeding in belly-deepwater through the tail and bordered by a few dark lowerbranch continued above the eyeand along while completelysubmerging their head the sideof the head. The split superciliumwas streaksalong upper tail coverts.Extensive white lessevident when viewed from the side. Toward sidesto rump and upper tail covertssimilar to (Smith 1982). Cox (1987) described the backof the headthe upperfork of the split PectoralSandpiper. foragingas peckingfrom the mud sur-

Volume4 I, Number 5 1361 Note the whitefeather tips to lowerscapulars. The mantlefeather edgingsare enttrelyruffms. The nape is slightlypaler than the crown.Note thedark feather shaft streaks. especially on the upper wing coverts. Duxbury Beach. Massachusetts. September 16. 1987.Photo/Mark Km'pryzk.

faceor deepprobing when in belly-deep 1987, fed on mudflats at low tide (R.J. Hybridization in shorebirds water, repeatedly"dunking its bill below Swindleypers. comm.). the surface with forward and downward No information is available to indi- The question is still unresolvedas to head movements,seemingly identical to cate whether sexual dimorphism exists whether Cox's Sandpiper is a true spe- the method of when in Cox's Sandpipers as in Pectoral cies or a hybrid, possiblybetween C. feedingin similar circumstances."Cox's and Sharp-tailed sandpipers.However, acuminata and C. ferruginea or C. me- Sandpipersthat Smith (1982) described Smith ( 1982:pers. comm.) hasobserved lanotosand C. ferruginea (Lane et al. were"often in the companywith Sharp- size variation of Cox's Sandpiper in 1981; Cox 1987). Cox (1987) recently tailed and Curlew sandpipersand Ru- Australia similar to that of Pectoral compared many morphologicalfeatures fous-neckedStints [Cah'dris ruficollis]." Sandpiper. Smith (pers. comm.) men- of Cox's Sandpiper with those of Pec- Cox (1987) observed that birds were tions how "larger birds can look fairly toral and Curlew sandpipersand pro- mostlysolitary, although they tendedto squat at times, almost Red Knot (Cal- vided evidence suggestinga closerela- join largegroups of other calidridswhen idris canutus)like." The Massachusetts tionship to the two species.However, flushed. bird appearedstocky both in the hand this question may not be settled until and in the field. either the breeding grounds of para- melanotos are found or additional specimenevidence clearly indicates hy- Dry, rocky upper tidal zone inter- DISCUSSION brid origin. spersed with Saltmarsh cordgrass Compared with mostgroups of birds, (Spartina alternillora) and coveredex- To date, all records (but see below) hybridization among shorebirds has tensivelywith rotted and freshwrack of of Cox's Sandpiper have been in south- been rarely reported. Hybridization has algae and Eelgrass (Zostera marina). eastern Australia during the austral been documented more often among Foraged primarily in the rotted wrack summer (September-March), where it the oystercatcher complex (Bancroft and tidal pools along the rocky section occurs primarily in the company of 1927;Jehl et al. 1973;Jehl 1978, 1985), of the beach. Only once was the bird Rufous-neckedStints and Sharp-tailed a poorly differentiated superspecies observedfeeding in sand poolsalong the and Curlew sandpipers, which breed group that collectivelyhas a continuous tide line. primarily in during the temper- breeding range from Alaska to Tierra In Australia, Cox's Sandpiper has ate summer.The lack of reportsin Aus- del Fuego. In , hybridiza- beenreported from a variety of wetland tralia during their winter suggeststhat tion between pied and black forms of , including muddy shoreline it might breed in Siberia (as hypothe- the Variable Oystercatcher (Haemato- shallows,brackish and freshwaterlakes, sizedby Marchant et aL 1986). The ap- pus unicolor) has also been described marshesand sewageponds (Smith 1982; pearance of a Cox's Sandpiper on the (Baker 1975). F.T.H. Smith pers. comm.). An indi- east coastof , where va- Hybridization hasalso been reported vidual present at Werribee, Victoria, grantsfrom Siberiaoccasionally appear, in avocetsand , which are in the September24, 1987, to eady November further strengthensthat supposition. same suborder (Charadrii) as oyster-

1362 American Birds, Winter 1987 Note bill lengthrelative to headlength and the slight droop of the blackbill tip. The bill is blackand the baseof the lowermandtble and upper mandibleimmediately anterior to naresare slightlypale. Duxbury Beach,Massachusetts. September 16, 1987. Photo/Mark Kaspryzk. catchers.Principe (1977) describedan resemble those of Cox's Sandpiper, al- 1987 season.Smith reportedsingle birds "avostilt" (Recurvirostra americana x thoughsome featuresdo not agreesuch at Werribee (November 10, 1986), Lake Himantopus mexicanus) from Califor- as "... upper tail-coverts white, with Murdeduke (December 20, 1986) and, nia•and Pierce(1984) discusseshybrid- irregular sagittateand V-shaped marks for the first multiple report, he saw a ization in New Zealand stilts, Himan- of dusky." However, Ridgway's mea- "flock" of three in New South Wales topus spp. However, the "avostilt" re- surementswere closeto thosegiven for (March 8, 1987) (F.I.H. Smith pers. sultedfrom birds held captive for at least Cox's Sandpiper in Marchant et al. comm.). Cox (1987) observeda mini- five years and cannot be considered a (1986). Ridgwaygave no descriptionof mum of four individuals north-north- natural occurrence. Other apparent the bird's soft parts. west of Adelaide, one of which appar- shorebird hybrids include a Greater Roger B. Clapp at the United States ently remained almost four months Golden-Plover (Pluvialis apricaria) x National Museum kindly reexamined (December 6, 1986-April 4, 1987). Lesser Golden-Plover (Pluvialis dom- the Cooper's Sandpiper specimen and The 1987-1988 field season has al- inica), based on measurements (Borg provided more details. The measure- ready yielded three reports from Aus- 1976), and a Black-winged Pratincole ments and descriptionhe obtained were tralia. Single adult birds were found (G!areola nordmanni) x Common Pra- nearly identical to those presentedby during late August in South Australia tincole(G. pratincola)(Walmsley 1970). Ridgway (1919). The legsand bill ap- and at Werribee (September 24, 1987) Gray (1958) lists earlier apparent pearedas if they were originally darkish (fide Robert J. Swindley); Australia's shorebirdhybrids, however, only a few throughout: most importantly, the bill first documented sightingof a juvenile scolopacidsand no calidrids were cited. was not decurvedas in Cox's Sandpiper. Cox's Sandpiper occurred October 3, Based on this information, the possi- 1987, with photographsobtained (fide bility of the specimen being a Cox's Robert J. Swindley). Sandpiperwas ruled out. The confusing Further records of Cox's Sandpiper Cox's and Cooper's sandpipers question then remains: what hybrid or outside Australia will likely increase aberrant plumage does this individual now that more observers are on the The Cooper's Sandpiper (Calidris represent? alert. Eventual knowledge of parame- cooperi) is known only from the type !anotos' true distribution and abun- specimencollected at Long Island, New dance in Australia, along with addi- York, on May 24, 1833, by William Recent sight records tional life history information, should Cooper (Ridgway 1919). Could this provide further clues as to this bird's specimenrepresent an early record of Sightings of Cox's Sandpiper have taxonomic status. Based on the increas- what is now called Cox's Sandpiper? been increasing recently from south- ing number of field sightings,the limited Many of the plumage characters of eastern Australia, where at least nine plumagevariability betweenindividuals Cooper's Sandpiper (Ridgway 1919) birds were sighted during the 1986- and the apparent scarcityof hybrid cal-

Volume 41, Number 5 1363 ldrlds, Cox's Sandpiper may, in fact, LITERATURE CITED MARCHANT, J, T PRATER, and P represent a valid species. HAYMAN 1986 Shorebirds an Iden- tification Guide to the of the BAKER, A. J. 1975. Morphologicalvaria- tion, hybridizationand systematicsof World. Houghton Mifflin Company, Boston. New Zealand Oystercatchers(Charadri- ACKNOWLEDGMENTS iformes:Haematopodidae). Journal of PARKER, S. A. 1982. A new sandpiperof Zool., Lond. 175:357-390. the genusCalidris. S. Aust.Nat. 56(4) We especiallywish to thank Mano- BANCROFT, C. 1927. Breedingbirds of 63. met Bird Observatory,along with the Scammon's Lagoon, lower California. PIERCE, R. J. 1984. Plumage,morphology Condor 29:29-57. numerous students and volunteers who and hybridizationof New Zealand stilts, BORG, S. 1976.Hybrid Pluvialisapricaria Himantopus spp. Notornis 31(2): 106- participatedin the shorebirdbanding x Pluvialis dominica. I1-Merill No. 17: 130, illust. program. Specialthanks to JonathanL. 36. Atwood for his help and contributions COX, J. B. 1987. Somenotes on the per- PRINCIPE, W. L., Jr. 1977. A hybrid in manuscript preparation, and addi- plexingCox's Sandpiper. S. Aust. Ornith. American x Black-necked Stilt Condor79( 1):128-130, illust. tional thanksto Linda E. Leddy,Trevor 30:85-97. Lloyd-Evans, Simon A. Perkins and GRAY, A. P. 1958. Bird Hybrids. Tech. RIDGWAY, R. S. 1919. The Birdsof North Commun. No. 13, London, Common- Bruce A. Some for their helpful com- and Middle America. U.S. Nat. Mus wealth Agricul. Bureaux. Bull. 50, pt. 8, p. 289-290. ments. David C. Morimoto kindly JEHL, J. R., Jr., M. A. E. RUMBOLL, and alerted us to contacts in Australia. We J.P. WINTER. 1973. Winter bird pop- SMITH, F. T. H. 1982. undone Stilt 2:10-11. wish to acknowledge our Australian ulationsof Golfo San Jose,Argentina. correspondents, Fred T.H. Smith, Bull. Br. Ornith. Club. 93:56-63. WALMSLEY, J. G. 1970. Une giareole de Robert J. Swindley, Shane A. Parker, JEHL, J. R., Jr. 1978.A new hybridoyster- Nordmann Glareola nordmanni en Ca- catcher from , Haemato- and John B. Cox for supplyinginfor- margue,premiere observation et premier pus leucopodusx Haematopus ater. cas de nudification pour la France mation on field characters and on cur- Condor 80:344-346, illust. Alauda 38:295-305, 3 pls (Eng. Sum- rent sightingsof the Cox's Sandpiper. __. 1985. Hybridization and evolutionof mary). Roger B. Clapp at the National Mu- oystercatcherson the pacificcoast of Baja seum clarified our questions on Coo- California. In P. A. Buckley,M. S. For- per's Sandpiper. Martha U. Rustigian ster, E. S. Morton, R. S. Ridgely and typed the manuscript. Camille M. Ro- F. G. Buckley (Eds). Neotropical Orni- thology. Allen Press,Kansas. --Manomet Bird Observatory,Box mano patiently listened to and com- LANE, S. G., F. W. C. VAN GESSEL and 936, Manomet, MA 02345 (Kasprzyk mented on more than one hundred sto- C. D. T. MINTON. 1981. A hybrid and Harrington), 257 Exchange nes concerningthe Cox's Sandpiper. ?Corella 5(5):114-115. Street,Millis, MA 02154 (Forster)

1364 AmericanB•rds, W•nter 1987