Identification of Black Rat (Rattus rattus) Signs in Mangrove Forests of Harra Protected Area in South of Iran

Black rat (Rattus rattus) is the only rodent present in the mangrove forests of Harra biosphere reserve in Hormozgan province. Identifying signs of this nocturnal species is the preliminary study for other ecological researches in this fragile ecosystem. Signs of this species were studied with 18 random transects in three growth formations (deltaic، island and coastal formations) of grey mangrove (Avicennia marina). Signs of black rat in mangrove forests are nests، food stations، shelters، feces، tracks and food remains. Nests are the most significant and useful sign which consists of branches and leaves of mangrove tree. Nest is the most suitable sign for black rat studies and can be used forecological investigations such as habitat selection. Food stations are nearly flat places that food is transferred there for eating and usually are located on the nests. Shelters are found in the trunk of mangrove trees and only observed in island formations. Because of the tide، feces and tracks are not reliable signs and can be observed accidentally. By investigating food stations it was determined that black rats in mangrove forests are omnivore species which feed on all species of crabs، shells،fishes، insects، seeds of mangrove trees and birds (eggs، nestlings and adults).