Novelty responses in a bird assemblage inhabiting an urban area

ECHEVERRÍA, ALEJANDRA; VASSALLO, ALDO IVÁN

ETHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Berlín; Año: 2008 p. 616 - 624

0179-1613

Alejandra Isabel Echeverría (AIE) and Aldo Iván Vassallo (AIV). NOVELTY RESPONSES IN A BIRD ASSEMBLAGE INHABITING AN URBAN AREA Abstract. Neophobia, or the hesitancy to approach or feed at novel objects or on novel foods, is an important factor influencing the foraging behavior of animals. Variation in the intensity of novelty responses may influence the probability that an individual will explore and locate unfamiliar resources, determining in part the degree of ecological plasticity. Mechanisms that underlie the differential neophobia response may involve complex interactions with the environment. In a previous study it was observed that some urbanized species inhabiting  suburban marshes of Cortaderia selloana (a relatively simple and predictable ecosystem as compared to urban areas), in particular House Sparrows (Passer domesticus L., 1758) and Shiny Cowbirds (Molothrus bonariensis J. F. Gmelin, 1789), showed stronger neophobic reactions, compared with more specialized species. Because the post-fledging experience in a greater diversity of habitats or in habitats that are more complex may contributes to a reduced neophobia, we explored the role of inhabitating a more complex environment on novelty responses displayed by bird species. The present study was carried out at the city of Mar del Plata and the results were compared with those obtained from the suburban marsh study. We found unexpectedly high levels of neophobia in House Sparrows. Shiny Cowbirds showed a somewhat neophilic response: they performed longer visits to the feeder when novel objects were present. The proportion of individuals that visited the feeders during treatments in relation to the total number of individuals arriving in the surrounding area was lower at the urban setting for House Sparrows and Eared Doves (Zenaida auriculata Des Murs, 1847), whereas Shiny Cowbirds showed both a higher effective number of visits to the feeder and no differences between habitat types in this variable. The results are discussed regarding invasion success and feeding innovation in Shiny Cowbirds.