Behavioral response of coexisting sparrow species to heterospecific song playback in the central Monte Desert, Argentina

M. CECILIA SAGARIO; VICTOR R. CUETO

Maturín, Venezuela

Congreso; VIII Neotropical Ornithological Congress; 2007

Neotropical Ornithological Society

Behavioral interactions may reflect underlying ecological relationships, which could have consequences in species coexistence. Knowledge of these interactions may therefore provide valuable clues when trying to understand community organization. Our objective was to compare behavioral responses of birds to heterospecific playback, particularly between intra-guild species and cogeneric ones.  We worked in a mesquite open woodland in Monte desert, Argentina, with 4 coexisting Emberizid species: 3 share the same food resource, grass seeds (Zonotrichia capensis, Saltatricula multicolor and Poospiza ornata), and the fourth species, Poospiza torquata, is a foliage insectivorous during the breeding season.  Territorial birds of every species were focally exposed to three types of stimuli (control –Furnarid-, heterospecific and conspecific songs) inside their territory. During playback, latency time to flight towards the speaker, minimum distance and number of flights and songs were recorded. We found that intra guild species did not respond to each other’s playback (i.e., didn’t approach to the speaker nor increased their singing rate compared to control and sang less than when exposed to conspecific’s playback). Contrarily, P. ornata responded to P. torquata’s playback, but we didn’t observe the opposite situation. P. ornata response, for example, may be misdirected because of song similarities (which still wouldn’t explain why the response is asymmetrical) or may reflect interference competition for sheared limiting resources, such as nest sites, which are known to be very similar. In this case, asymmetrical response could be explained by the fact that P. ornata, a migrant species, arrives to the area later in the breeding season, when P. torquata is already established. Further studies are needed to evaluate if this behavioral response is indeed reflecting an underlying ecological interaction between these two cogeneric species.