ORNITOLOGIA NEOTROPICAL 15: 319–330, 2004 © The Neotropical Ornithological Society NEST SITES OF TERMITARIUM NESTING BIRDS IN SE PERU Donald J. Brightsmith Duke University Department of Biology, Box 90338, Durham NC 27708, USA. E-mail: [email protected]. Resumen. – Nidos de aves en termiteros arbóreos en el sureste del Perú. – En todas las áreas tropicales del mundo hay aves que anidan en los nidos arbóreos de termitas. Este comportamiento de anidamiento en termiteros está poco documentado y ha sido objeto de pocos estudios científicos. Este artículo reporta la estación de anidamiento y las características de los nidos de seis especies de aves que anidan en termite- ros arbóreos en el bosque húmedo tropical del suroeste de la cuenca Amazónica. El Jacamar grande (Jaca- merops aurea) excavó nidos en termiteros hechos por la termita Constrictotermes cavifrons, este representa el primer registro de aves de este género anidando en termiteros. El Jacamar castaño (Galbalcyrhynchus purusi- anus), el Trogón colinegro (Trogon melanurus), el Trogón coroniazul (T. curucui), el Pihuicho tui (Brotogeris sanctithomae) y el Pihuicho alicobalto (B. cyanoptera) usaron termiteros de Nasutitermes corniger. También se reporta un nido del Jacamar frentiazulada (Galbula cyanescens) en el margen de una pequeña quebrada. Las excavaciones hechas por todas las especies de aves en los termiteros de N. corniger consistieron de un túnel angosto con inclinación positiva que lleva a cámaras de anidamiento casi hemisféricas. Las excavaciones de los pihuichos Brotogeris tuvieron entradas significativamente mas angostas y con un mayor ángulo de incli- nación que las del Trogón colinegro. Las excavaciones de los pihuichos Brotogeris fueron similares a las reportadas en la literatura para otros miembros de este mismo género. Las excavaciones del Trogón coline- gro y el Trogón coroniazul fueron similares entre ellas y similares las de otros miembros del “violaceous subclade” del género Trogon pero difieren de las excavaciones poco profundas hechas por miembros del “elegant subclade” de este mismo género. Abstract. – In all tropical areas of the world there are birds that nest in the arboreal nests of termites. The termitarium nesting behavior is poorly documented and has been the object of few scientific studies. This paper reports on the nesting season and nest characteristics of six species of termitarium nesting birds from moist tropical forests in the southwestern Amazon Basin of Peru. Great Jacamar (Jacamerops aurea) excavated nests in termitaria made by Constrictotermes cavifrons; this represents the first record of birds nesting in termitaria of this genus. Purus Jacamars (Galbalcyrhynchus purusianus), Black-tailed (Trogon melanurus) and Blue-crowned (T. curucui) trogons, Tui (Brotogeris sanctithomae) and Cobalt-winged (B. cyanoptera) parakeets used Nasutitermes corniger termitaria. A single nest for Bluish-fronted Jacamar (Galbula cyanescens) in a stream bank is also reported. Nest excavations made by all species in N. corniger termitaria consisted of narrow up sloping tunnels leading to roughly hemispherical nesting chambers. Excavations of Brotogeris parakeets had significantly narrower entrance tunnels and entered at significantly steeper angles than those of Black-tailed Trogons. The excavations of Brotogeris parakeets were similar to those reported in the literature for other members of this genus. The excavations of Black-tailed and Blue-crowned trogons are similar and similar to other members of the “Violaceous subclade” of the genus Trogon but dif- fer from the shallow excavations made by members of the “Elegant subclade” of this genus. Accepted 24 January 2004. Key words: Galbalcyrhynchus purusianus, Trogon melanurus, Trogon curucui, Brotogeris cyanoptera, Brotogeris sanctithomae, Jacamerops aurea, Galbula cyanescens, nest site characteristics, nest excavation, termite, Nasutitermes corniger, Constrictotermes cavifrons. 319 BRIGHTSMITH INTRODUCTION opies 35–40 m high, with emergents reaching 60 m (Robinson et al. 1990, Terborgh & The great structural complexity of tropical Petren 1991). Over 560 bird species have lowland forests provides birds with many been recorded in the 15 km2 surrounding the nesting niches not available to temperate spe- station (Terborgh et al. 1984). Alpha diversity, cies (Koepcke 1972, Terborgh 1985). One defined here as the number of species with structural element of these forests exploited overlapping home ranges, exceeds 160 species by nesting birds throughout the tropics is in some areas of the mature forest, making arboreal termite nests or termitaria (Hind- this one of the most diverse avian communi- wood 1959). Despite its global distribution, ties in the world (Terborgh et al. 1984, 1990; termitarium nesting has been subject to few Gentry 1988, Karr et al. 1990, Robinson et al. scientific investigations and comparatively lit- 1990). tle is known about this behavior (Reed & Data were collected from September to Tidemann 1994, Brightsmith 2000). Termi- November 1993, 1995, 1996, and 1997. As a taria nesters include species from the pre- result, only species nesting during this time of dominantly burrow nesting families the year were recorded. Additional species Galbulidae (Jacamars), Coraciidae (Kingfish- likely use termite mounds at other times of ers), and Bucconidae (Puffbirds), and species year. Nests were found using three methods: from the predominantly tree nesting families 1) checking all termitaria located in 13 ha of Trogonidae (Trogons) and Psittacidae (For- plots; 2) walking trails and systematically shaw 1989, Fry et al. 1992, Collar 1997, 2001; checking each termitarium found; and 3) fol- Rasmussen & Collar 2002, Tobias 2002). This lowing the characteristic sounds of calling suggests that there are at least two paths by adult and nestling birds (Brightsmith 1999a, which birds made the evolutionary transition 2000). to nesting in termite mounds (Brightsmith Termitarium length, width and depth were 1999a). Unfortunately, detailed analysis of the measured directly with tape measurers or esti- ecological importance and evolutionary his- mated from the ground using 5-cm diameter tory of termitaria nesting is inhibited by a lack PVC tubes with 1.5 x 1.5 mm grid on one of basic nest site descriptions. To help fill this end. These values were then converted to gap in our knowledge, I report on the nesting cm using the height and distance from the of six species of birds that used arboreal ter- termitaria (Brightsmith 2000). The volume of mite mounds in a moist tropical lowland for- the termitarium was calculated assuming it est in southeastern Peru. was an ellipse with diameters equal to the measured height, width and depth (Lubin et METHODS al. 1977). Entrance angle for excavations was measured with a clinometer. Cavity character- This study took place in mature and late suc- istics were measured using a rigid metal tape cessional tropical floodplain forest surround- measure. Nests visibility was recorded from ing Cocha Cashu Biological Station in Manu the ground and each nest was scored as National Park, Peru (11°54’S, 71°18’W; Ter- clearly visible, obscured by leaves or in the borgh et al. 1984). This site lies at about 400 m shadows at the bottom of the termitarium. elevation on the boundary between tropical Characteristics of the nest excavations were and subtropical moist forest (Holdridge compared among species using t-tests and 1967). The mature forests of this site are esti- differences in nest visibility among species mated to be over 200 years old and have can- were tested with c2 tests (Gibbons 1985). 320 TERMITARIUM NESTING IN PERU Data are presented as mean ± SD unless oth- mes cavifrons (subfamily Nasutiterminae). One erwise reported; P-values < 0.05 are consid- mound was still occupied by the termites ered significant. whereas the other was not. The nests of Great Jacamars were 7.0 and 3.8 m above the RESULTS ground in termitaria that were 82 and 201 l in volume. The one nest that could be measured Six bird species were found using termite had an entrance 10 cm high and 6 cm wide. mounds during this study: Purus (Galbalcyrhyn- The floor sloped down from the entrance at chus purusianus), and Great (Jacamerops aurea) 30° into a chamber about 8 cm wide and 25 jacamars, Black-tailed (Trogon melanurus) and cm long that hugged the side of the tree. In Blue-crowned (T. curucui) trogons, Tui (Broto- the other nest, the tunnel sloped up at an geris sanctithomae) and Cobalt-winged (B. angle of +40° into the chamber. Both nest cyanoptera) parakeets. Each is discussed below holes were clearly visible and not obstructed in detail. by leaves or other vegetation. Termitaria made by C. cavifrons were Purus Jacamar. I observed a group of at least extremely rare in the study area, I found only six Purus Jacamars excavating a cavity in a ter- two in 13 ha of forest surveyed, and only mitarium on 20 October 1997. The termitar- seven in total. These termite mounds were ium was in open swamp forest dominated by also spatially clumped. All seven were within a Ficus trigona, with a dense Heliconia understory 7-ha triangular-shaped area, despite the fact (see Terborgh 1983 for a description of this that searches were conducted throughout an swamp). At night, the group roosted in the area over 1500 ha. The architecture and place- cavity together. On 6 November, I checked ment of C. cavifrons termitaria was nearly the termitarium for the last time; the birds identical for all seven encountered: all were were still attending it but I could not confirm attached to the main boles of large living the presence or absence of eggs because the Dipteryx micrantha trees (diameter at termitar- entire interior of the chamber was not visible. ium height = 67 ± 12.1 cm, range = 51–81 The termitarium was 4.7 m above the ground, cm, N = 6) with no branches or lianas passing 143 l in volume, built and inhabited by Nasuti- through or near the mounds. The mounds termes corniger termites (subfamily Nasutitermi- were on average 7.3 ± 1.91 m above nae).