In this study, bird species of Hoynat Island, which is one of the two biggest islands on and around the Black Sea coast, and population trends of these species in a year and nesting site selection of breeding bird species, were examined. Hoynat Island is also the largest know area to show breeding behaviour for European shag in Turkey. Observations were conducted between 2011 and 2017 years. It was found three bird species preferred for nesting Hoynat Island throughout the year. These species are great cormorant (Phalacrocorax carbo Linnaeus 1758), European shag (Phalacrocorax aristotelis Linnaeus 1761) and yellow-legged gull (Larus michahellis J. F. Naumann 1840). These species show breeding and incubation behaviours on the island and surrounding rocks. While P. aristotelis uses the island as a short-term stopover when it first comes to the area, it stays in the rocks on the tunnel then and during the incubation process. P. carbo and L. michahellis do not use the rocks on the tunnel and only P. carbo stays for a while on the top of trees in the upper part of the tunnel. P. carbo and L. michahellis use the island as a stopover and incubation area. Using the island and surrounding as a nesting site, P. aristotelis, P. carbo and L. michahellis have reached the highest population in June. During this month, 170 P. aristotelis, 670 P. carbo and 475 L. michahellis were counted. It was found that breeding preparations of the birds in the study area started in February and hatching continues until June.