Breeding Behavior and Threats to Saunders's Tern (sternula Saundersi) at Sir Bani Yas Island, United Arab Emirates

The numbers of Saunders's Tern (Sternula saundersi) are decreasing globally, and the species' biology remains poorly known. This study used camera traps to determine clutch size, incubation period, hatching and fledging success, and threats to breeding Saunders's Terns on Sir Bani Yas Island, United Arab Emirates. Six nests were selected in each breeding season (12 nests total) from April to June 2017 and 2018 (out of 9 and 8 nests, respectively). The mean clutch size during the two-year period was 1.50 +/- 0.22 SE and 1.33 +/- 0.21 eggs per nest in 2017 and 2018, respectively. The mean incubation period was 18.97 +/- 0.33 days. The mean hatching success was 62.5% in 2017and 45% in 2018. Out of the 12 nests, three nests did not produce any successful chicks, as one nest failed due to predation by feral cats and two due to anthropogenic factors. The monitoring of chicks with camera traps was limited due to their active movement patterns after the third day, but 80-100% of chicks successfully departed nests, and the colony fledged 75-86% of known chicks.