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ORNITOLOGIA NEOTROPICAL 14: 121–125, 2003 © The Neotropical Ornithological Society

OBSERVATIONS OF AGGRESSIVENESS AND TERRITORIALITY AMONG SPECIES OF RHINOCRYPTIDAE IN A RAIN FOREST FRAGMENT IN SOUTHERN CHILE

Alejandro Correa Rueda1,3 & Javier A. Figueroa2

1Fundación Senda Darwin, Chiloé, Chile. 2Centro de Estudios Avanzados en Ecología y Biodiversidad, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, CP 6513677, Chile. E-mail: [email protected]

Observaciones de agresividad y territorialidad entre especies de Rhinocryptidae en un fragmento de bosque templado húmedo del sur de Chile. Key words: Aggressiveness inter-species, Rhinocriptydae, Chiloé rain forest, Chile.

All five species of in the Family Rhino- tid species (Sieving et al. 2000). All three cryptidae inhabiting the temperate forests of rhinocryptids have omnivorous and opportu- austral South America are endemic to these nistic diets, depending on regional and sea- temperate forests (Johnson 1967, Meyer de sonal changes in the availability of Schauensee 1982, Arctander & Fjeldså 1994). invertebrates and fruits (Armesto et al. 1987, Three of them, the Chucao (Sce- Correa et al. 1990, Sabag 1993, Rozzi et al. lorchilus rubecula), the Huet-huet (Pteroptochos 1996). The aim of this study was to register tarnii) and the Andean Tapaculo (Scytalopus behavioral patterns, including degrees of magellanicus ) are sympatric inhabitants of the aggressiveness, in Chucaos , Huet- temperate rain forest of Chiloé Island (Short huets, and Andean Tapaculos during their 1969, Correa & Figueroa in press). Through- breeding period in a forest fragment located out their entire latitudinal distribution range, on the north-eastern part of Chiloé Island. these rhinocryptids live in primary and sec- This study constitutes the first report of ondary forests, and show preference for for- aggressive behavior among rhinocryptids est understories (Johnson 1967). However, inhabiting the rainforests of southern Chile. lowland forests in southern Chile have The study was conducted between 20 become increasingly fragmented through fell- October and 20 November 1994 in a forested ing and burning, thus decreasing available area near Manao, c. 50 km east of Ancud habitat for feeding and nesting of rhinocryp- (41°S, 73°W), on the northern coast of Chiloé ______Island. Observations were carried out within 3Current address: Felix de Amesti 991, Depto 502, a primary forest fragment (Mandiola forest) c. Las Condes, Santiago, Chile. E-mail: alcorru@ 15 ha in size that had been intervened for hotmail.com wood extraction. The forest canopy was dom-

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FIG. 1. Areas occupied by the rhinocryptid species in a forest fragment of Chiloé Island. inated by various tree species including Notho- ent mosses. We observed activity and move- fagus nitida, Drymis winteri, as well as a few ment patterns of two pairs of Chucao Myrtaceae such as Amomyrtus luma, A. meli Tapaculos for a period of 17 days (Correa and Myrceugenia planipes. Numerous species of 1999). A pair and a female were captured and vines grow within the forest interior (e.g., banded with color rings. They were observed Luzuriaga radicans, Philesia magellanica) as well as daily, every two hours between the 06:00 h epiphytes (Gesneriaceae: Mitraria coccinea and and 18:00 h. Moreover, we recorded the daily Sarmienta scadens), lichens (e.g., Usnea sp.), activity of pair of Huet-huets every four ferns (Hymenophyllum) and a variety of differ- hours between 06:00 h and 18:00 h during a

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30-day period. Finally, we registered the activ- ond pair of Chucao Tapaculos. The Andean ity of a pair of Andean Tapaculos every two Tapaculo pair occupied an area of c. 0.1 ha of hours between 06:00 and 18:00 h during 17 forest, overlapping the area occupied by the days. We defined the approximate limits of two other species (Fig. 1). breeding territories within each species by All three rhinocryptid species used the joining various observation points (sensu M. same habitat of forest every day, going out of Willson pers. com.). Observation points were the estimated limits of their territory only on defined following the birds leaving their nests rare occasions. The forest habitats used by in search for food and back again, or until the four pairs were highly heterogeneous, they were lost from view. We estimated the consisting of small and shallow streams with size of the areas used in the search for food, abundant vegetation cover in various stages or nest materials, and recorded inter-species of decomposition and large dead trees. The aggressive interactions. By means of a single three species of Chilean rhinocryptids seem “sudden attack” (Lorenz 1978) using fog nets to display the same behavioral patterns. placed at ground level, we captured both indi- When one of the two individuals of a given viduals of a pair of Chucao Tapaculos that pair was away searching for food (between 10 had two nestlings in their nest. We also cap- and 30 min), its place at the nest was taken by tured the female of a second pair with three its respective mate. Also, nests were cleaned chicks in its nest. All captured birds were and maintained regularly and each pair gener- color-banded. ally followed the same route on the ground The first pair of Chucao Tapaculos (nest- while searching for prey for themselves or 1, Fig.1) used c. 0.34 ha of forest during the their nestlings. The small streams were regu- study period. Its nest was meticulously con- larly visited during the entire day, each time structed in a Myrceugenia ovata tree close to the the individuals left the nest. edge of the forest fragment, c. 1.5 m above We registered different degrees of aggres- ground level. It consisted of dry leaves, siveness between species and pairs. No sign branches, lichens, and mosses. The second of agressiveness was observed between the pair (nest-2) used c. 0.29 ha of forest during two Chucao Tapaculos; one of the pairs only of the period of study. The dense nest was rarely entered the territory of the other. In constructed over branches of quila, contrast, we observed inter-species aggressive and was made of dry leaves, mosses, lichens behavior. The most aggressive species proved and materials of the same C. quila, c. 2 m to be the largest sized Huet-huet (c. 154 g and above ground level. Both nests were sepa- 25 cm). An adult Huet-huet traveling with rated by a distance of c. 50 m (Fig. 1). The two of its nestlings and mate was seen attack- Huet-huet pair had two nestlings in a hole ing an adult Chucao Tapaculo (c. 38 g and 17 within a dead dombeyii tree, c. 4 m cm) of nest-2, violently entering the nest and above the ground. The Huet-huet pair obser- assaulting it, but without causing physical vation points were defined following the damage to the chicks. Furthermore, the same birds leaving their nests in search for food pair of Chucao Tapaculos (nest-2) was and back again, or until they were lost from aggressive towards one of the adult Andean view. The pair used an area of c. 1.5 ha. Its Tapaculos (c. 10 g and 10 cm) of nest-3 when nest was c. 140 m away from those of the two the latter was searching for food in the vicin- Chucao Tapaculo pairs (Fig. 1). The nest of ity of nest-2. However, overall, only a small the Andean Tapaculo pair was located under number of aggressive encounters were a C. quila shrub, c. 10 m from that of the sec- detected among rhinocryptid species in this

123 CORREA RUEDA & FIGUEROA study. These observations suggest that the Foundation Fellowship. This is a contribution degree of aggressiveness among Chilean rhi- of Research Program 2 to CASEB. A. Correa nocryptids increases with territory size and dedicates this work to Museu de Zoología, body size. Barcelona, España, and particularly to Drs J. We suggest that the aggressive behavior Pique and F. Uribe. of the Huet-huet towards the Chucao Tapa- culo is associated with the defense of its nest- REFERENCES lings and not with an attempt of the Huet- huet to attack the nest of the Chucao Tapa- Araya, B., & H. Millie. 1988. Guía de campo de las culo. Nest predation among rhinocryptids has aves de Chile. Editorial Universitaria, Santiago, not been registered in Southern Chile. Addi- Chile. tionally, the aggression of the Chucao Tapa- Arctander, P., & J. Fjeldså. 1994. Andean tapaculos culo could be related to the fact that an of the genus Scytalopus (Aves, Rhinocryptidae): Andean Tapaculo was approaching the nest A study of speciation using DNA sequence data. Pp. 205–225 in Loeschcke, V., J. Tomiuk, where the Chucao Tapaculo was brooding its & S. K. Jain (eds.). Conservation Genetics. nestlings. This study constitutes the first Burkhäuser Vertag, Basel, Switzerland. report showing that the three rhinocryptids Armesto, J. J., R. Rozzi, P. Miranda, & C. Sabag. breed simultaneously. We suggest that the 1987. Plant/frugivore interactions in South decrease in habitat availability due to increas- American temperate forest. Rev. Chil. Hist. ing temperate rainforest fragmentation in Nat. 60: 321–336. southern Chile will result in a reduction in the Correa, A., J. J. Armesto, R. Schlatter, R. Rozzi, & J. distance among nests, which in turn could C. Torres-Mura. 1990. La dieta del Chucao (Sce- result in an increase in the degree of aggres- lorchilus rubecula), un passeriforme terrícola sive behavior due to a reduced habitat avail- endémico del bosque templado húmedo de ability for territories and reduce availability of Sudamérica austral. Rev. Chil. Hist. Nat. 63: 197–202. resources. Finally, the results suggest that the Correa, A. 1999. Observaciones sobre el compor- Huet-huet has the adequate traits (aggressive- tamiento de rubecula (Rhinocrypidae) ness and size) that enable it to displace the en época de reproducción. Not. Mens. Mus. Chucao Tapaculo and the Andean Tapaculo Nac. Hist. Nat. (Santiago) 339: 13–16. in forest fragments similar in size to the one Correa, A., & J. A.. Figueroa in press. Observa- studied. However, a significant reduction in ciones sobre la reproducción de tres Rhi- the size of the fragment could force the nocriptídos del bosque templado de Chiloé, migration of the Huet-huet because it needs a Chile. Bol. Chil. Ornitol . larger forested area. Johnson, A. W. 1967. The birds of Chile and adja- cent regions of Argentina, Bolivia and Perú. ACKNOWLEDGMENTS Volumen II. Platt Establecimientos Gráficos, Buenos Aires. A. Correa greatly appreciates M. F. Wilson’s Lorenz, K. 1978. Fundamentos de la etología. Estudio comparado de las conductas. Edi- and J. J. Armesto’s invitation to collaborate in ciones Paidós Ibérica, Barcelona. Proyecto Chucao. Karl Bardon and Toni de Meyer de Shauensee, R. 1982. A guide to the birds Santo helped us in fieldwork. We thank Toni of South America. Academy Natural Sciences de Santo for providing the bibliography. We of Philadelphia, Philadelphia, Pennsylvania. thank A. Muñoz and J. F. Hernández for Rozzi, R., J. J. Armesto, A. Correa, J. C. Torres- important comments and suggestions on the Mura, & M. Sallaberry. 1996. Avifauna de manuscript. JAF is supported by A. Mellon bosques primarios templados en islas deshabi-

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tadas del archipiélago de Chiloé, Chile. Rev. Argentina. Ibis 111: 239–240. Chil. Hist. Nat. 69: 125–139. Sieving, K., M. F. Willson, & T. L. de Santo. 2000. Sabag, C. 1993. El rol de las aves en la dispersión Defining corridor functions for endemic birds de semillas en el bosque templado secundario in fragmented south-temperate rainforest. de Chiloé (42ºS). Tesis de Magister, Univ. de Conserv. Biol. 14: 1120–1132. Chile, Santiago, Chile. Short, L. 1969. Observations on three sympatric species of tapaculos (Rhynocriptidae) in Accepted 3 July 2002.

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