Food shortage and predation are the main factors limiting the breeding success of many colonial seabirds. The aim of this study was to examine whether they influence breeding success of Arctic Terns Sterna paradisaea in a colony of 99 breeding pairs at Kaldbaksbotnur on the island of Streymoy, Faroe Islands. In 2003, we investigated clutch size, hatching success, food provisioning to chicks, kleptoparasitism, and predation, and the number of fledged chicks. Clutch size was on average 1.65 (±0.48) eggs/clutch with a hatching success of 100%. Food provisioning rates were low with 0.47 (±0.18) feeds per nest per hour. Most prey items were small (c. 32 mm long), and terns showed high rates of intraspecific kleptoparasitism. Attacks by avian predators were occasionally observed, mainly by Herring Gulls Larus argentatus, but were unsuccessful in all observed cases. Counts of fledged chicks indicated average breeding productivity of 0.22 chicks per pair. Our results suggest that breeding success in this colony was mainly affected by food shortage, possibly limited sandeel Ammodytes spp. availability. Predation appears to be less important, but could occur at a low rate. The results are consistent with recent evidence showing that seabirds that feed on sandeels currently have limited breeding success in the North Atlantic region.

Atlantic seabirds

CC BY 3.0 NL ("Naamsvermelding")

Nederlandse Zeevogelgroep

Jochen Schreiber, & W. Daniel Kissling. (2005). Factors affecting the breeding success of Arctic Terns Sterna paradisaea in a colony at Kaldbaksbotnur, Faroe Islands. Atlantic seabirds, 7(3), 97–105.