236 ShortCommunications and Commentaries [Auk, Vol. 113 ment of Madagascarfor permissionto study their red data book, part 1, 3rd ed. International Coun- ; P. Daniels for transportationto and accomo- cil for Preservation and International Union dation at the Duke University field camp;J. Graetz for the Conservation of Nature and Natural Re- for her unpublishedobservations; to G. Schatzof the sources,Cambridge, United Kingdom. Missouri BotannicalGarden, who provided housing DEE,T. J. 1986. The endemic birds of Madagascar. and logisticalsupport; T. Schulenbergfor a transla- International Council for Bird Preservation, tion; and C. Jouanin,who graciouslyallowed me to Cambridge,United Kingdom. use the collections of the Museum National d'Histoire G^DOW,H. 1883. Catalogueof the birds in the Brit- Naturelie, Paris. I thank B. Beehler, R. Bleiweiss, J. ish Museum. Vol. 8, Cichlomorphae,part 5. Brit- Graetz, D. Mason, T. Moermond, K. Parkes, G. Schnell, ish Museum, London. C. Wolf, and S. Yamagishifor helpful commentson KING,W.B. 1981. Endangeredbirds of the world. earlier drafts. W. Feeny drew the figure. Funds for SmithsonianInstitution Press,Washington, D.C. this researchwere providedby a RogerTory Peterson LAhlGP,A•D, O. 1990. Guide to the birds of Mada- Institution Research Grant and a Crowder Memorial gascar.Yale Univ. Press,New Haven, Connect- Conservation Grant from the World Nature Associ- icut. ation.Support during writing wasprovided by a Hen- L^V^UDEN,L. 1932. •tude d'unepetite collection ry Nathan Netzer and Bernard Netzer Brouchoud d'oiseauxde Madagascar.Bull. Mus. Hist. Nat., Scholarshipfor the Study of Wild Bird Life and the Paris, 4 (2nd ser.):629-640. Department of Zoology, University of Wisconsin- L^V^UDEN,L. 1937. Supplement.In Histoire phy- Madison. sique, naturelie et politique de Madagascar,vol. 12, oiseaux (A. Milne-Edwards and A. Grandi- LITERATURE CITED diet, eds.). Soci•t• d'Editions G•ographiques, Maritimes et Coloniales, Paris. A•I^DON, D. 1950. The Hawaiian honeycreepers MILON, P., J.-J.PETTER, AND G. PO,NDPa•N,•SOLO. 1973. (Aves, Drepaniidae). Bull. Am. Mus. Nat. Hist. Oiseaux,2 vols. Faune de Madagascar35:1-263. 95:151-262. MOUNTFORT, G. 1988. Rare birds of the world. Ste- APPERT,O. 1970. Zur Biologie der Vangaw(irger phen Greene Press,Lexington, Massachusetts. (Vangidae)s[idwest-Madagaskars. Ornithol. Beob. S•FORD, R., •ID W. DUCKWORTH(Eds.). 1990. A 67:101-133. wildlife surveyof MarojejyNature Reserve,Mad- APPERT,O. 1973. V•gel madagaskars.Natur und Mu- agascar.Int. Counc.Bird Preserv.Study Rep. 40: seum 103:124-129. 1-172. BENSON,C.W. 1971. The Cambridgecollection from SInLEY,C. G., AND B. L. MONROE, JR. 1990. Distri- the Malagasyregion, part II. Bull. Br. Ornithol. bution and taxonomyof birdsof the World. Yale Club 91:1-7. Univ. Press, New Haven, Connecticut. BENSON,C. W., J. F. R. COI,EnROOK-ROBJENT, AND A. YAMAGISHI, S., E. URANO, AND K. EGUCHI. 1992. The WILLtAMS. 1977. Contribution • l'ornithologie socialstructure of RufousVanga (Schetbarufa) in de Madagascar.Oiseau et R. F. O. 47:41-64. Ampijoroa, Madagascar.Pages 46-52 in Social CAMPBEI,L, B. 1974. The dictionary of birds in color. structureof Madagascarhigher vertebratesin re- Exeter Books, New York. lation to their adaptive radiation (S. Yamagishi, CARLQUIST,S. 1965. Islandlife. Natural HistoryPress, Ed.). OsakaCity Univ., Osaka,Japan. Garden City, New York. COLLAR,N. S., XhlDS. STUART. 1985. Threatened birds Received9 July 1993, accepted21 November1993. of Africa and related islands: The ICBP/IUCN

The Auk 113(1):236-239, 1996

Nesting of the Buff-throatedWoodcreeper ( guttatus)

ALEXANDER F. SKUTCH Quizarrd,8000 San Isidrode E1General, Costa Rica

The Buff-throatedWoodcreeper (Xiphorhynchus gut- forestsin more arid regions,and mangroves.It wan- tatus)is about 22 cm long and clad in the brownsand ders into lighter second-growthwoods and shady buffs widespread in its family. The sexesare alike. clearingsnear the old foreststhat are its true home. From Guatemala to Bolivia, Amazonian and south- Thesewoodcreepers usually are solitary, or one may easternBrazil, it inhabits rain forests,humid gallery join a mixed flock of woodlandbirds. They subsist January1996] ShortCommunications andCommentaries 237 largely on insectsand spidersthat they extractfrom ulatedto do so,if they bring long piecesof stiff bark crevicesin bark or epiphytes,while they climb up that will not enter while held transverselyin the bill. trees,using their long, spine-tippedtails for support, Then the bird may peck at the edgesof the orificein or outward alongbranches. An occasionalsmall lizard an effort to widen it. Late on an afternoon in mid- or frog varies their diet. They sleep singly in old February,continued loud tapping,audible ! 5 m away, woodpeckers'nests or other holes in trees. drew my attention to a solitary woodcreeperham- When I published my life history of this wood- mering, with strong,woodpeckerlike blows, at a gap creeper (Skutch 1981), ! had, after many years of in a dead but fairly sound bambootrunk. For about searchingin forestswhere the birds were not rare, half an hour, in the waning light, she continued to found only three of their nests.The first, inaccessibly peck,at intervalsentering the bamboo'scentral hol- high, was watched for many hours at all stagesof the low and coming out again. She pulled loose fibers nesting,the secondcontained infertile eggs,and the from the edgesof the aperture,which alreadyseemed third was prematurelylost. Later, ! found four more wide enough.Twice she called, loudly and clearly, nests, all within reach. At these nests ! confirmed che-e-e-r,with a slight roll. conclusionsreached from study of the first nest, and Stiff flakes of bark from tree trunks are the main determinedincubation and nestlingperiods more ac- materialsof Buff-throatedWoodcreeper nests. The curately than was possibleat the inaccessiblenest. birdsusually bring onepiece at a time, held crosswise The studyhere reportedwas made,from 1972to 1987, in the bill. When a pieceis too long to passthrough on or near our nature reserve, Los Cusingos, near the doorway in this manner, it is usually dropped Quizarr• (9ø20'N,83ø38'W) in the valley of E1General, after a brief struggle, insteadof being inserted end- on the southern Pacific slope of Costa Rica, at an wise. After the nestlingsdeparted the nest in the altitude of 740 m. timber bamboo, ! cut it open and found the cavity Nestsand eggs.--Like other ,the Buff- filled to a depth of 18 cm with hundreds, if not throated Woodcreepernests in diverse closedspaces. thousands,of pieces of stiff bark. The largest mea- The first nest was in a decayingstem of a clump of sured6.4 by 5.0 cm and when dried had a massof 3.2 tall timber bamboos(Bambusa vulgaris), in front of my g. Another piece was 8.5 by 3.0 cm (3 g) and the study window and at the edge of a large tract of rain heaviestpiece, thick and irregular in shape, had a forest.These stems are hollow, with cavitiesup to 10 massof 3.7 g. ! did not attemptto countall the pieces cm wide, divided into chambersby transversewalls becausemany appearedto be tiny fragmentsof larger at the nodes.The firstsepturn below the oval doorway piecesthat had decayedwhile remaining in the nest in the side had rotted out, or perhapshad been re- for severalrainy months.The woodcreepermust have movedby the ,and the nest restedupon made hundreds of trips bringing so much material. the second,50 cm below the doorway. Two nestswere Thesebirds carry bark to their nestsin spurtsof in chambers,of irregular shapeand much more spa- concentratedactivity separatedby long intervals:six ciousthan the woodcreepersneeded, amid the maze trips in 25 rain, sevenin 17 rain, and five in 11 min. of thick aerial roots of a massivestrangling fig tree Occasionally, they bring a contribution when they (Ficussp.) that surroundedthe trunk of a mufiecotree return for a spell of incubation and even while at- (Cordiabicolor) in a pasture,close by the forest. Access tending nestlings. A few piecesof foliaceouslichens to the chamberswas through a vertically elongated may be mixed with the bark. ! never found more than gap, about35 cm high, betweenthe roots.The effec- one woodcreeperengaged in preparing a nest. tive width of these openingswas about 3 cm--too Chapman (1938) counted more than 7,000 frag- narrow to admit my hand laid flat. Another nest was ments of bark and dead wood in a nest beneath the in a hollow, decayingtrunk of a guava tree (Psidium elevated floor of a building set upon posts in the guajava)close by our house. A little farther away a narrow clearing amid the forest on Barro Colorado woodcreepernested in a horizontalcavity in the head Island in Gatfin Lake, Panama. In Trinidad, Belcher of an old, pollared madera negra (Gliricidiasepium) and Smooker(1936) found eggsresting upon a bed that served as a living fence post. In a clump of pe- of weed stems,dead leaves,and plant down, all of jibayepalms (Bactris gasipaes) in the midst of a narrow which might have been carried into the hole in a strip of moderatelytall second-growthwoods with dead stump before the woodcreeperclaimed it. thick undergrowth, about 100 m from forest,a wood- Eachof six nestsin E1General containedtwo eggs creeperoccupied the stumpof one of the palms.The or nestlings,which is the number reportedfrom Trin- spiny, thin-shelledstump was 94 cm high and about idad and Tobagoby ffrench(1973). From only one of 15 cmin diameter.The eggswere located46 cmbelow my nestscould ! remove the eggs without jeopard- the open top. From this lowestnest, six othersranged izing them. In a nest among the fig-tree roots, the up to 5.4 m (measuredto the doorway) above the eggswere positionedon the level of the entrance, ground. from which ! could remove them uninjured with a Woodcreepersare not known to carvea new cavity, long-handledspoon. They were pure white, glossy, but they may enlarge or otherwise modify one that slightlytapering, almost equally blunt at the two poles, they find. Buff-throated Woodcreepersappear es- and measured30.0 by 19.9 ram, and 27.0 by 19.0 min. pecially apt to engagein this activity, and seemstim- In E1 General, five setswere laid in March, one ap- 238 ShortCommunications andCommentaries [Auk,Vol. 113

TABI•E1. Incubationby femaleBuff-throated Wood- TABI• 2. Feeding and brooding of Buff-throated creepers. Woodcreepers.

NestHours Sessions(min) Recesses(min) Nest Hours Nestlings TimesMinutes no. watched n ß (range) n • (range) no. watched No. Age (days) fed brooded 1 6.0 2 125 (99-151) 2 38.0 (33-43) 1 6 2 ca. 2 7 94+ 1 12.5 3 145 (111-181) 4 27.5 (25-34) 1 6 2 ca. 7 13 13 2 7.0 3 96 (91-107) 3 37.0 (28-47) 1 6 2 ca. 16 12 0 4 5.5 2 101 (94-108) 3 33.0 (30-37) 4 5 2 3 10 75 6 6.0 6 42 (18-58) 5 21.0 (3-48) 5 5 1 4 1 109 6 6.5 2 3 7 128

parently in mid-April, and one in mid-July.This last, infertile set appeared to be the secondof a wood- bationof the unseeneggs to the beginningof feeding creeperwhose young fledgedin late April. In Trin- the invisible nestlings.At another nest, the incuba- idad, five nestsof Buff-throatedWoodcreepers were tion period was at least18 days.This is one day longer found in March, June, and July (ffrench 1973). than the 17-dayperiod of the Spotted-crownedWood- Incubation.--At their nests, these Buff-throated creeper( affinis), whose eggs are incu- Woodcreeperswere not very shyand couldbe watched bated by both parents. The empty shells soon dis- through 8 x binocularswhile I sat without a blind appear;in the Buff-throatedWoodcreeper I did not about 12 m away. If undisturbed, they rarely incu- learn whether they were eaten or carriedaway in the bated for less than 1.5 h at a stretch and sometimes parent'sbill. At the late nest in the fig tree, the wood- twice as long (Table 1). Although, taking turns, my creepercontinued for no lessthan 29 daysto incubate wife, son, and I watched nest 1 continuouslyfrom infertile eggs. dawn to dusk (12.5 h) on 24 March 1972, the wood- Nestlings.--The newly hatched Buff-throated creeper'sactive day was much shorter than this. She Woodcreeperhas tightly closedeyes. Its dark gray did not emerge from the hole in the bambootrunk down, about 2 cm long, fails to concealits pink skin. until 0617, well after sunrise, and at 1521 on the clear The young bird peepsweakly and gapes,revealing a afternoon,she returned and remaineduntil nightfall. yellow mouth borderedby prominent white flanges. Of the 544 min in this interval, she was in the nest When a week old, dorsal pinfeathersbegin to erupt 434 min, or 80% of the time. The remainder was oc- from the skin.At 10 daysthey arelong but still closed, cupied by four recesses,each of about half an hour. and at 11 or 12 days the plumage begins to expand. At nest 6, near the house,the woodcreepersat for At 17 days body and wings are well feathered,but shorterintervals, probably because she was occasion- the head is still almost naked, and the rectrices are ally disturbedby human activity. On the morning almostcompletely enclosed in long sheaths.A day when I watched, only two of her six sessionswere later, when the crown is feathered,the young wood- curtailedby peoplepassing by, and she incubatedfor creeper resemblesan adult, but its central rectrices 70% of the time. are still ensheathed. In contrast to Lepidocolaptes In 37 h of prolongedwatches during incubation, woodcreepers,these nestlings were almost silent. Their we saw no changeover.Only oncedid anotherwood- infantine peepswere audible only when I was quite creeperappear while the attendantwas in or near the close to the nest. nest. On this occasion,the secondbird, possibly a From the single parent who attended them, the male,alighted beside the doorwayof the nest,where- nestlingsreceived ,, and an occasional upon the incubating bird emerged,and both flew lizard. Thesewere brought,one at a time, held in the away. tip of an adult'slong, slenderbill (Table2). A solitary Returningto her nest,a woodcreeperoften brought nestling,four daysold, receivedonly one lizard dur- a flake of bark to add to her already large accumu- ing the morning hours,but this substantialmeal ap- lation. During her absences,the eggswere sometimes pearedto satisfyit. During their firstdays, other young partly or wholly coveredby this loosematerial. Once, were fed at the hourly rate of about 0.5 mealsper beforeher eggshatched, a femaleentered with a large capita. Even when they were older, the rate rarely . These birds often called loudly with cheeror exceededonce per hour for each of them, but they chunotes when approachingtheir nests,with head oftenreceived fat larvae;occasionally, a parentbrought in the doorway,just after leaving, and even while a pieceof bark insteadof food. sitting unseenin the cavity. Occasionally,an incu- After the first few days, the woodcreeperswere bating female answeredcalls of a distantwoodcree- broodedlittle; when 9 or 10 daysold, the nestlings per, who might have been the neglectful father of were not covered,even at night. Parentscarried away her progeny. fecal sacsin their bills and kept the nestsclean. The At nest 1, 18 days elapsedfrom the start of incu- parentswere more silent during this part of the nest- January1996] ShortCommunications andCommentaries 239 ing cycle than while they incubated.When I visited In the breeding season,mainly from February or their nests,they remainedat a distance,neither com- March to June in E1 General, males advertise their plaining nor making hostiledemonstrations. A squir- presenceby frequent singing, usually while they cling rel (Sciurusgranatensis) that climbed over the guava unseenhigh amid densefoliage or vine tangles.Their tree that sheltered nestlingswas usually ignored by loud, clear, melodious notes, which have been com- the parent,but oncemy sonsaw her chasethe rodent. pared to those of the Northern Cardinal (Cardinalis Likewise, when a squirrel climbed down the fig tree cardinalis), are delivered in series of about 7 to 16, toward the cranny that contained nestlings, the par- often 7 or 8. Sometimesthe song is followed by sev- ent, who was present,made neither sound nor feint eral drawled notes, che-e-e-r, che-e-e-r, che-e-e-r in fall- of attack. These woodcreepers appear to depend ing cadence.It is heard throughout the day, but most wholly upon concealment,silence, and infrequent frequently in early morning, late afternoon,and when visits for the safety of their nestlingsin odd nooks sunshine breaks through clouds after an actual or difficult to find. threatenedshower. Singing malesare too widely dis- Departureof fledglings.--When I inserteda tiny, un- persed to form a lek. lighted electricbulb throughthe narrowgap between Another of woodcreepersin which males do the rootsinto the chamberin the fig tree, an almost not participate in nesting is ,of which alarming outburstof high, shrill notesemerged from two ,the Tawny-winged Woodcreeper(D. an- it. When I switched on the light, the outcry was re- abatina)and the Plain-brown Woodcreeper(D. fuli- peatedby the two featherednestlings who hitherto ginosa)have been adequatelystudied (Skutch 1969, has been so silent. Thereafter, they remained quiet Willis 1972). From fragmentary observations,I sus- while I peeredin with a small mirror. Two dayslater, pectthat the OlivaceousWoodcreeper (Sittasomus gris- these nestlings were silent while I inspected their eicapillus)falls into this category. Contrasting with nest, but one struck the mirror with a wing. After this pattern, malesof Streaked-headedWoodcreepers removing light, mirror, and ladder, I retired a short (Lepidocolaptes souleyetii), Spotted-crowned Woodcree- distance and watched. Soon a nestling silently pers(L. affinis),and Wedge-billedWoodcreepers (Gly- emerged,climbed up the trunk for about 120 cm, and phorhynchusspiurus) are known to cooperatewith their crept into the space between two thick branches. matesat all stagesof the nesting (Skutch 1969, 1981). Stubby-tailed,it still bore much natal down. By the To learn the distribution of these two patterns of nest following day, both young had vanished,aged 18 or attendanceamong the 60 speciesof Dendrocolapti- 19days. From another nest, two youngdeparted when dae, we need many more careful studies of their re- 19 days old. The lone nestling in the palm stub left production. at the age of 19 or 20 days. Two in the high nest where I could not seethem emerged20 days after I LITERATURE CITED first saw the parent carry in food. From another nest, two young vanishedwhen 18 daysold, leaving feath- BEI•C•IER,C., AND G. D. SmOOKER. 1936. Birds of the ersthat revealedthat they had been attacked.The full Colonyof Trinidad and Tobago--PartIV. Ibis 14: nestling period of the Buff-throated Woodcreeper is 792-813. 19 or 20 days. From these nestsin clearings,all the CHAPMAN,F.M. 1938. Life in an air castle.Appleton- fledglings promptly disappeared,probably into the Century Co., New York. neighboring forest. They did not return to sleep in FFRENC•I,R. 1973. A guide to the birds of Trinidad the nestswhere they were hatched,as certainwood- and Tobago.Livingston Publishing Co., Wynne- peckersdo. If the young who lost escaped wood, Pennsylvania. with no more seriousinjury, all five of the nestswhere SKt•TC•I, A.F. 1969. Life histories of Central Amer- the eggs hatchedwere successful,an exceptionally ican birds. III. Pacific Coast Avifauna no. 35. good record in the tropics. SKt•TC•I,A. F. 1981. New studiesof tropicalAmer- Behaviorof males.--The sexes of Buff-throated ican birds. Publ. Nuttall Ornithol. Club, no. 19. Woodcreepers are indistinguishable in the field. WII•LIS, E. O. 1972. The behavior of Plain-brown However, more than 75 h of watching at six nests, Woodcreepers.Wilson Bull. 84:377-420. covering all stagesfrom building to fledging, failed to yield evidencethat two individuals were interested Received5 October1994, accepted 25 April 1995. in a nest.