CESIMAR - CENPAT   25625
CENTRO PARA EL ESTUDIO DE SISTEMAS MARINOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
TROPHIC INTERACTIONS DURING CHICK REARING BETWEEN KELP GULLS AND CAYENNE AND ROYAL TERNS
Autor/es:
NICOLÁS SUÁREZ; CRISTIAN MARINAO; PABLO YORIO
Reunión:
Congreso; Ornithological Congress of the Americas (XVII RAO/XXIV CBO/XCV AFO; 2017
Institución organizadora:
AVES ARGENTINAS
Resumen:
Terns are one of the most affected groups by gulls, through predation, kleptoparasitism and competition for nesting sites. These interactions have been reported in Patagonia, where Cayenne and Royal terns (Thalasseus sandvicensis eurygnathus and T. maximus, respectively) nest in mixed-species colonies with the Kelp Gull (Larus dominicanus). However, trophic interactions between these species have not been yet evaluated. During 2014, we assessed their diet during the chick stage at the Bahía San Blas Protected area, through the analysis of Kelp gull chick stomach samples (n=66) and direct observation of prey deliveries (DO) in Cayenne and Royal terns (n=1747 and 1014, respectively), in addition to stable isotope analysis (SIA) of chick whole blood (n=10 per species).Engraulis anchoita was the main prey shared by the three species. In both tern species, this was one of the three most frequent prey (~30% DO; ~ 50% SIA), together with two silverside species, while in the Kelp Gull it showed a frequency of ~35% (both methods) followed in similar frequencies by Cynoscion guatucupa derived from recreational fishery waste. Both analysis indicated that the overlap between the trophic niches of Kelp Gulls and each tern species was low (Czekanowski Index