The reserve spans over 40 ha (99 acres) of desert shrub land and 10 km (6.2 mi) of lakes and is home to 26 identified species of reptiles, nine of mammals and 39 species of plants. It provides a sanctuary for 19 animal species considered endangered, as well as flocks of between 300 and 500 flamingos and over 360 other bird species, of which 158 are migratory.[1] Rare species observed at Al Marmoom include the Egyptian Nightjar and the butterfly Coeliades Anchises Jucunda, which is native to the island of Socotra, off Yemen.[4]