Investigating the breeding population and soil texture of breeding sites of four Terns, Crab Plover, and Western Reef Heron on the islands of Khan, Nakhilou, Om-al-Gorm, and Tahmadon in Mond Marine National Park in Persian Gulf carried out in the spring and summer in 2015. Twenty-two species of water birds identified on the islands. Eight species of them were breeder and reminder (14 species) was passage. The dominant species was Bridled Tern Sterna Anaethetus with 170427 breeder pairs that had bred on sandy ground under the Atriplex bushes. The populations of Lesser Crested Tern Sterna bengalensis and Greater Crested Tern Sterna bergii were 19933 pairs in Nakhilou and Om-al-Gorm Islands that had bred also on the Sandy ground. The breeder population of Western Reef Heron Egretta gularis was 12, 72, and 45 pairs in Om-al-Gorm, Nakhilou, and Khan Islands respectively. The nests have been built on the short bushes. The breeder population of Crab Plover Dromas ardeola was 2266 on Nakhilou and 481 on Om-al-Gorm. The nests of this species have been built under ground in tunnels. Soil texture of tern’s nests sites in Nakhilou, Island consisted of 94.6% sand, 1.3% silt and 4.1% Clay, and under Atriplex bushes was 95.4% sand, 1.7% silt and 3.9% Clay. Soil texture of terns nesting sites in Om-al-Gorm, Khan, and Tahmadon consisted of 93.4% sand, 1.7% silt, and 4.9% clay; 92.8% sand, 2.7% silt and 4.7% clay, 89.4% sand, 3% silt and 7.6% clay respectively. The soil texture of the nesting sites on four islands did not differ significantly (p=0.05).
