The Behavior of Black-Banded Woodcreepers (Dendrocolaptes Picumnus)
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Condor 84~272-285 0 The Cooper Ornithological Society 1982 THE BEHAVIOR OF BLACK-BANDED WOODCREEPERS (DENDROCOLAPTES PICUMNUS) EDWIN 0. WILLIS ABSTRACT.-In forests and nearby second growth at Manaus, Brazil, Black- banded Woodcreepers (Dendrocoluptespicumnus) regularly foraged with army ants as well as away from ants. Like ant-following Dendrocolaptescerthia and Hylexetastesperrotii in the same study area, they tended to wait or hitch slowly on vertical thick trunks, then sally to or peck at prey. They were intermediate in dominance statusand in use of perchesnear the ground, where ants flushed most prey. Birds of all three speciesalso foraged high above the ground when the ants sent probes up trees. Sleek-headed (presumed female) Black-banded Woodcree- pers supplanted their ruff-headed mates and helped in their disputeswith neigh- boring pairs; one or both birds of a pair sang near roost sites in morning and evening; and pairs trespassedto a limited extent on their neighbors’ areas. Large young were out of the nest with parents as early as July and as late as January, then wandered away from them. Breeding birds molted at about the time young left. At other study sites, the related svecies D. hofmannsi and D. platyrostris behaved like D. pi&m&. Woodcreepersof the genusDendrocolaptes are pers to my presence. I captured and color- among species of birds that regularly follow banded 13 individuals at the Reserva. I took army ants for flushed prey in neotropical for- weights with Pesola scales and cloaca1 tem- ests(Willis and Oniki 1978). The behaviorally peratures with a Schultheis thermometer. little-known Black-banded Woodcreeper (D. Vocalizationswere recordedwith a Uher 4000- picumnus) proved to be an important species Report S tape recorder at 19 cm/s. in the ant-following guild that I studied for over a year near Manaus, Brazil. Here I report MEASUREMENTS AND SEXUAL on studiesof Black-bandedWoodcreepers, and DIFFERENCES compare their behavior with that of related I examined 638 museum specimensof Black- woodcreepers. banded Woodcreepers, measuringculmen and wing chord for most, and did not find strong STUDY AREAS AND METHODS sexual differences in color or measurements. I briefly studied Black-banded Woodcreepers Average wing length of males exceeded that of at severallowland forest localities:Nappi Creek females by 0.5-2.9 mm in seven of eight pop- and Bartica in Guyana (On&i and Willis 1972); ulations considered, but overlap was great Umbria, Leticia, and Mitu, Colombia; Limon- within each population. Moreover, the 0.5-mm cocha and Putuimi in Ecuador; Yarinacocha difference was in nominate D. p. picumnus, and Andoas in Peru; Diamantina, Palhao, Car- which is the subspeciesat Manaus. Females auari, Serra do Navio, Almeirim, and the weighed more than most males in small sam- Campina Reserve (near Manaus) in Brazil. At ples from Surinam (combined x = 88.7 g, Reserva Ducke, Brazil, I studied them almost II = 6) and eastern Peru (X = 86.3 g, y1= 5). daily from 3 July 1973 to 27 August 1974. From Nicaragua northward (X = 61.0, y1= 6) Reserva Ducke (entranceat 2”55’S, 59”59’W) and in the Colombian and Venezuelan Andes is a 10 X 10 km forest tract of the Instituto (X = 73.8 g, IZ = 4), the specimens of D. pi- National de Pesquisasda Amazonia (INPA), cumnus were small, but sexes overlapped just north of Manaus. Tall upland forests at widely in weight. 100-l 20 m elevation are broken here and there In Dendrocolaptes species at Reserva by medium-height forests in sandy valleys of Ducke, two types of birds formed pairs: a sleek- small streams at 50-60 m elevation. Experi- headed individual dominated one that ruffed mental forestry tracts line an entrance road to up its head and breastevery time its mate came a laboratory clearing, and neighboring areas near. In Barred Woodcreepers, one sleek- are irregularly cleared for maniac and other headed bird that I collected proved to be a crops (Willis 1977). female, while two collected ruff-headed birds By watching with binoculars from behind were males (Willis, unpubl.). I assumed,there- swarms of ants (Eciton burchelli), I accus- fore, that “ruffed” birds were males and tomed individual Black-banded Woodcree- “sleeked” birds were females in Black-banded [2721 BLACK-BANDED WOODCREEPERS 213 Woodcreepers also, even though both types remained frozen. (In many passerines,the thin weighed about the same at Manaus (K = 82.8 and high “keening” associatedwith freezing is g, yt = 14). difficult for humans to hear.) I noted freezing Collectors have not recorded the head ruff- in responseto alarm calls of other birds (Plain- ing of their D. picumnus specimens, but the brown Woodcreeper, Dendrocinclafuliginosa, precedingparagraph is consistentwith the fact 8 times; D. picumnus, 2; Black Nunbird, Mon- that more males (303) have been taken than asa atra, 2; keening of Rufous-throated Ant- females (240). Sleek-headed birds normally bird, Gymnopithysrujigula, 1). Once, one clung were retiring at Manaus, leaving the subordi- close to a tree as Little Chachalacas (Ortalis nate ruff-headedbirds to foragenear the ground motmot) flew past. Woodcreepers generally and near me. However, it is possiblethat males seem to be protectively colored, and the pale sing more than females at dawn and dusk (see streakson a Black-banded Woodcreeper may below), a factor that could also bias collecting have increased its resemblance to furrowed in favor of males. bark or to spaces between epiphyte leaves. Streaking appears to be correlated with rapid OBSERVATIONS OF BLACK-BANDED hitching along dark trunks in woodcreepers; WOODCREEPERS unstreakedand barred forms wait more or use VOICE well-lighted trunks. Song. Black-banded Woodcreepers at Manaus Fleeing. These woodcreepers often fled to sangdescending series of 15 to 20 simple chirps, avoid danger, sometimes by sidling quickly lasting almost 2 s (Fig. 1A): “kie-ie-ie-ie-ie-ie- around a tree trunk, then freezing or hitching ie-ie-ie-ie-ie-ie-ie-ee-eu-eu-er.” Barred Wood- upward on the far side of the trunk. During creepers (Dendrocolaptescerthia) at Manaus pauses,the bird often turned its head, flitted had a similar but slower song, of 8 notes in the tips of its wings or wrists, or peered around 1.4 s. A Planalto Woodcreeper (Dendroco- the trunk (Fig. 2A). An isolated snarl might laptesplatyrostris)from Fazenda Barreiro Rico, break the silence. Another method was flight S&o Paulo, gave a slow evening song like that to other trees, without the usual downward of a Barred Woodcreeper, 12 notes in 2.3 s swing to a lower perch characteristic of for- (Fig. 1C), but one from Fazenda Klabin, Espir- aging moves. When the presumed danger was ito Santo, (courtesy of Michael Gochfeld) sang a human or low-flying raptor, the bird often a fast songlike that of a Black-banded Wood- climbed to large branches 20-35 m above the creeper, 18 notes in 2.3 s (Fig. 1C). ground. Once, at the sound of a distant gun- Rattles. Series of short chirps at 6-8 per s, shot, a bird dropped instead to a low trunk; fluctuating in volume and changingirregularly on another occasion, a woodcreeper snarled in quality “ee-ee-ee-ee-ie-ie-e-e-ie-ei-” and so and backed down a trunk when macaws (Ara on (Fig. lF, H), were frequent after disputes ararauna) flew over. The bird might sleek the or in responseto playback of recordings.They head or ruff it when near the observer; ruffing sometimes graded into songs. could refer to the following behavior pattern, Squeals. Loud series of several “squeeh” however, as it was most characteristic of a notes were given during fights. returning bird or one reluctant to move as I Snarls.A growlingnoise followed by a squeal, approached. “chauhhh-eesk,” (Fig. 1G) seemed to be an Snarling, usually with fleeing, was specifi- alarm call. At times the last note of a snarl was cally recorded at the approach of hawks and less piercing, perhaps a different call. falcons (Micrastur ruficollis, 4; Leucopternis Grunts. Short faint series,“ uk-uk-uk,” were albicollis, 2; unidentified hawk, 2; Buteogallus given at nearby competitors. Barred Wood- urubitinga, I), at the soundof avian alarm calls creepersin Panama grunted similarly. (Dendrocincla fuliginosa, 4) at a gunshot or Peepsongs.The brief songsof fledglingBlack- passingmacaws, to nets (4) and to me (5). The banded Woodcreepers (Figs. lD, E) consisted snarlsat me were usually a less sharp version, of 12 or so chirps in 1 s, the song at times apparently without a sharp rise in pitch at the rising and then falling rather than falling end. I noted fleeing or nervous wing-flitting in throughout: “wh-e-e-e-e-e-e-e-e-e-e-up.” response to me and to another person who came up to me (even though the bird involved ALARM BEHAVIOR had been ignoringme), to passingcars, to alarm Freezing. I commonly saw birds simply freeze, calls (Dendrocincla fuliginosa, Pithys albi- pressingtheir bodies againstthe limb or trunk frons, 2; Ortalis motmot) and to a hawk (Leu- and remaining immobile for several seconds copternisalbicollis). to minutes. Immature birds stoppedpeepsing- Other birds often performed alarm move- ing while they froze. Occasionallya bird snarled ments or calls following the sharp snarls of as it froze, but I detected no sound while it Black-banded Woodcreepers, even when the EDWIN 0. WILLIS TINEID SECDIIDS FIGURE 1. Sonogramsof Black-banded (B-b) and Planalto (P) woodcreeper vocalizations. A. B-b, song, Manaus. B. P, song, Fazenda Klabin, Espirito Santo (courtesyof Michael Gochfeld). C. P, song at Fazenda Barreiro Rico, Slo Paul0 (note changeof scales).D and E. B-b, peepsongsof young, Manaus. F. B-b, rattles, Manaus.