PARROT NESTING IN SOUTHEASTERN PERU: SEASONAL PATTERNS AND KEYSTONE TREES Author(s): DONALD J. BRIGHTSMITH Source: The Wilson Bulletin, 117(3):296-305. 2005. Published By: The Wilson Ornithological Society DOI: http://dx.doi.org/10.1676/03-087A.1 URL: http://www.bioone.org/doi/full/10.1676/03-087A.1 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Wilson Bulletin 117(3):296±305, 2005 PARROT NESTING IN SOUTHEASTERN PERU: SEASONAL PATTERNS AND KEYSTONE TREES DONALD J. BRIGHTSMITH1 ABSTRACT.ÐParrots that inhabit tropical lowland forests are dif®cult to study, are poorly known, and little information is available on their nesting habits, making analysis of community-wide nesting patterns dif®cult. I present nesting records for 15 species of psittacids that co-occur in southeastern Peru. The psittacid breeding season in this area lasted from June to April, with smaller species nesting earlier than larger species. Why smaller species bred earlier is uncertain, though it may be related to interspeci®c competition for nest sites or variations in food availability. This study identi®ed two keystone plant resources used by nesting parrots: Dip- teryx micrantha (Fabaceae) and Mauritia ¯exuosa (Arecaceae). Local threats to these plant species are discussed. Received 25 August 2003, accepted 14 April 2005. Nesting is a critically important stage in the est areas shrink, conservationists must priori- natural history of all bird species. Reproduc- tize their conservation efforts. Large, old trees tive failure has caused numerous conservation and the cavities they contain are vital for the crises, so knowledge of nesting habits is crit- persistence of many cavity-nesting birds ical (Ratcliffe 1967, Herkert et al. 2003). The (Mawson and Long 1994, Poulsen 2002). nesting ecology of many tropical species re- However, cavity nesters usually do not use mains poorly documented, especially for can- trees in proportion to their abundance, sug- opy nesters in dense, lowland tropical forests. gesting that some tree species are more im- The family Psittacidae is the most endangered portant than others to these birds (Martin and large avian family in the world, making its Eadie 1999, Monterrubio and Enkerlin 2004). study a conservation priority (Bennett and In this study, I compiled nesting records for Owens 1997, Collar 1997). Most of our 15 species to determine which trees were most knowledge of parrot nesting comes from an- important to the nesting parrot community in ecdotal accounts by early collectors (Huber southeastern Peru. 1933), regional avifaunal compendia (Cherrie 1916, Havershmidt 1968), detailed studies of METHODS individual taxa (reviewed in Masello and Study area.ÐI studied parrot nesting in the Quillfeldt 2002), and the monumental com- Departamento de Madre de Dios in south- pendium of Forshaw (1989). eastern Peru. The primary site was the Tam- New World parrot diversity is highest in the bopata Research Center (138 079 S, 698 369 W; western Amazon Basin, where communities 250 m in elevation) on the border between the commonly include more than 15 species (Roth Tambopata National Reserve (275,000 ha) and 1984, Montambault 2002). This diversity Bahuaja-Sonene National Park (537,000 ha). peaks in southeastern Peru, where 18 to 20 The center is located in a small (,1 ha) clear- species have been reported at various sites ing surrounded by a mix of mature ¯oodplain (Terborgh et al. 1984, Foster et al. 1994). forest, riparian successional forest, Mauritia However, the nesting season for all but ®ve ¯exuosa (Arecaceae) palm swamps, upland species in the region remains undocumented, forest, and bamboo (Foster et al. 1994, Gris- making community-level analyses impossible. com and Ashton 2003; DJB pers. obs.). The Here, I report on the nesting season for 15 forest is classi®ed as tropical moist forest species of sympatric parrots inhabiting low- (Holdridge 1967). The site is adjacent to a lands of the western Amazon Basin in south- 500-m-long, 30-m-high riverbank clay lick, eastern Peru. where up to 1,000 macaws and parrots gather Land clearing and pressures on global for- daily, resulting in high parrot densities in the est resources are constantly increasing. As for- area (Brightsmith 2004a). Annual rainfall is 3,200 mm. The dry season extends from April 1 Duke Univ., Dept. of Biology, Durham, NC 27708, to October, during which monthly rainfall av- USA; e-mail: [email protected] erages 90±250 mm (Brightsmith 2004a). Ad- 296 Brightsmith x COMMUNITY-WIDE PARROT NESTING IN PERU 297 ditional nesting records come from Posada tree. One pair, consisting of a wild bird and a Amazonas Lodge in the Native Community of hand-raised bird released to the wild, nested In®erno (128 489 S, 698 189 W; 195 m in ele- in wooden nest boxes in 2 years (see Nycan- vation; 2,800 mm annual rainfall; Pearson and der et al. 1995 for a description of the nest Derr 1986, Brightsmith and Aramburu 2004) boxes). Three nests were in ¯oodplain forest and Cocha Cashu Biological Station in Manu (one ,10 m from the river edge) and nine National Park (118 549 S, 718 189 W;400min were in terra ®rme forest. elevation; 2,000 mm annual rainfall; Terborgh Blue-and-yellow Macaw (Ara ararauna).Ð 1983, Terborgh et al. 1984). These two sites Seventy-two nests in at least 50 different cav- are characterized by similar vegetation and ities were recorded. Most cavities (47 of 50) dry seasons, and they are located 50 km north- were in dead Mauritia ¯exuosa palms. Be- northeast and 250 km northwest of Tambopata cause it is dif®cult to climb dead palms, only Research Center, respectively. 21 nest trees were climbed, and nest contents Nesting records.ÐNesting records consist- were checked infrequently. I estimated that ed of two types: con®rmed nests and birds at egg laying occurred in November (n 5 9), De- cavities. Con®rmed nests were locations cember (n 5 2), and January (n 5 2). I con- where I observed eggs or chicks. Observa- ®rmed ¯edging in late February (n 5 1), tions of birds at cavities, where contents were March (n 5 4), and May (n 5 1). Fifty of not checked, were included only when birds these nests were in a 3-ha section of naturally were observed repeatedly at the cavity and dying Mauritia ¯exuosa palm swamp, where where behavioral cues suggested incubation or dead palms occurred at a density of .200 per feeding of young. Single observations of birds ha (A. Bravo and DJB unpubl. data). Sixteen at cavities were not included, as parrots may nests were in a small (,0.25 ha) section of a visit cavities when not breeding. swamp being managed to encourage nesting Most of the nesting records were from July of Blue-and-yellow Macaws (Nycander et al. to August (1998) and November to April 1995). Three other nests were in tall, dead (1999 to 2003) in Tambopata and September palms that rose above the surrounding vege- to November (1993, 1995, 1996, and 1997) in tation in an otherwise healthy palm swamp. Manu. I collected additional unpublished nest- Two nests were in ¯oodplain forest in dead ing records from researchers and guides with Iriartea palms ,10 m from the river edge. experience working in southeastern Peru. One additional nest was in an unidenti®ed These other observers were stationed at Tam- dead, hollow tree in terra ®rme forest, 10 m bopata year-round. from the edge of a cliff that overlooked the Data analysis.ÐI tested the relationship be- Tambopata River. The cavity was a deep, tween body size and the onset of breeding us- open-topped tube, similar in structure to a hol- ing a rank correlation of body mass versus low palm. month of ®rst breeding and a t-test (a50.05) Scarlet Macaw (Ara macao).ÐI studied 55 of month of ®rst breeding for large (.250 g) clutches at 26 different nest sites. I was certain versus small (,250 g) psittacids (Gibbons of ®rst-clutch initiation for 40 nests: late Oc- 1985). Body-mass data are from Dunning tober (n 5 1), November (n 5 32), and De- (1993). cember (n 5 7). When the ®rst clutch was lost or did not hatch, 35% (7 of 20) of the birds RESULTS re-laid in the same nest. Second clutches were Red-and-green Macaw (Ara chlorop- initiated in late December (n 5 4) or early tera).ÐTwelve nests of this species were January (n 5 3). Fledging took place in Feb- monitored in Tambopata between 1993 and ruary (n 5 4), March (n 5 14), and April (n 2003. I determined laying date for nine nests: 5 2). No eggs from second clutches hatched. September (n 5 1), November (n 5 7), and Nests were found in natural cavities of live December (n 5 1). Fledging was con®rmed in Dipteryx micrantha (n 5 6), live Hymenaea January (n 5 1) and March (n 5 5; Table 1).