Efecto de la asociación y actividad de un cleptoparásito sobre el comportamiento trófico de su hospedador

GARCÍA GERMÁN OSCAR; FAVERO MARCO; VASSALLO ALDO IVÁN

ORNITOLOGIA NEOTROPICAL

NEOTROPICAL ORNITHOLOGICAL SOC

Año: 2011 vol. 22 p. 505 - 516

1075-4377

Between April and September 2006 and 2007 we studied the effect of kleptoparasitism on the foraging behavior of its host. The study was conducted at Mar Chiquita Lagoon (Argentina, 37º46’S, 57º27’W). Our study system consisted of the Brown-hooded Gull (Chroicocephalus maculipennis) and the Grey-hooded Gull (Chroicocephalus cirrocephalus) as kleptoparasitic species, and the American Oystercatcher (Haematopus palliatus) as a host species. Focal observations were performed on oystercatchers feeding under two different feeding scenarios, that is in presence or absence of kleptoparasites. No differences were found in the comparison of hosts’ foraging effort in presence or absence of kleptoparasites. However, prey capture rate and the duration of each capture event were significantly affected by the presence of the kleptoparasites, with kleptoparasitized hosts showing higher prey capture rates and lower duration of capture events. These changes in the foraging behavior can be regarded as two avoidance strategies performed by hosts in presence of kleptoparasites. In addition, the larger capture rates and shorter duration of captures in kleptoparasitized hosts might also be linked to the association of gulls to more efficient or experienced oystercatchers. The exploration of these new questions would require studies with banded individuals to allow the observation of same birds under contrasting scenarios (i.e., with and without kleptoparasites).