Foraging areas of Cayenne, royal and South American terns breeding in northern Patagonia, Argentina

GATTO, ALEJANDRO; YORIO, PABLO; DOLDAN, MARÍA DEL SOCORRO; VILLANUEVA GOMILA, LUJÁN; CABRAL, KARINA

Congreso; 25th International Ornithological Congress; 2010

Cayenne (Thalasseus sandvicensis eurygnathus), royal (Thalasseus maximus) and SouthAmerican terns (Sterna hirundinacea) breed sympatrically in Patagonia, Argentina. Very little isknown on the breeding foraging areas and feeding patterns of these species and thus studies areneeded to understand their role in coastal ecosystems and develop adequate managementstrategies. We present information on the use of foraging areas by these species at a mixedspecies colony in the Punta León Protected Area (43º 04‘ S, 64º 29‘ W), and in the Punta LomaProtected Area (42° 49‘ S, 64° 53‘ W), Chubut, Argentina. Radio-transmitters were deployed oneight nesting adults of each species, which were tracked during the late incubation. Feedingareas were identified during foraging trips by means of radio-telemetry from the coast, using twofixed tracking stations for each colony, consisting each of two attached 9-element Yagi antennae.Terns foraged mostly between the colony and the first 15 km from the coast, and 35 km awayfrom the colony. However, lack of signal reception in some of these trips, indicate that foragingcan also take place in waters further away. In general, individual birds were consistent in the useof one particular area. Implications for foraging area partitioning between terns and the coastalmanagement and conservation guidelines will be discussed.