Status of Terns on Nakhiloo Island, Persian Gulf, with Emphasis on Lesser Crested Terns <i>Thalasseus bengalensis</i>

Lesser Crested Tern Thalasseus bengalensis (LCT) is the second most abundant tern in the Persian Gulf region. Stratified random sampling was used to census the colonies on Nakhiloo Island, Iran. On average, 9.45 eggs, 2.2 early chicks, and 1.1 empty nests with material were counted in each 1×1 m plot in late June 2022. Analysis of those results indicated the breeding population of LCT on Nakhiloo Island to be 31 786 pairs. Other terns and plovers were also present in five of seven LCT subcolonies. Variable sea-surface temperatures (SST) with a slight upward trend and a decrease in chlorophyll a (Chl a) were evident in waters surrounding the island during 2002–2021, but it is unknown whether the tern population has or will be affected by changes in the food web caused by these evident changing oceanographic conditions. Results show that Nakhiloo Island is a hotspot for tern colonies in the Persian Gulf. Anthropogenic factors, including climate change, will threaten its future suitability, requiring more specific conservation management than currently practiced.