236 ShortCommunications and Commentaries [Auk, Vol. 113 ment of Madagascarfor permissionto study their red data book, part 1, 3rd ed. International Coun- birds; P. Daniels for transportationto and accomo- cil for Bird 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 (Xiphorhynchus 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 along branches.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 woodcreepers,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 woodcreeper,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.