 Pelicans are very large birds with very long bills characterised by a downcurved hook at the end of the upper mandible , and the attachment of a huge gular pouch to the lower . The slender rami of the lower bill and the flexible tongue muscles form the pouch into a basket for catching fish and , sometimes , rainwater , though in order not to hinder the swallowing of large fish , the tongue itself is tiny . They have a long neck and short stout legs with large , fully webbed feet . Although they are among the heaviest of flying birds , they are relatively light for their apparent bulk because of air pockets in the skeleton and beneath the skin enabling them to float high in the water . The tail is short and square . The wings are long and broad , suitably shaped for soaring and gliding flight , and have the unusually large number of 30 to 35 secondary flight feathers . 
