Bird anatomy Birds have a four-chambered heart, in common with mammals, and some reptiles (mainly the crocodilia). This adaptation allows for an efficient nutrient and oxygen transport throughout the body, providing birds with energy to fly and maintain high levels of activity. A ruby-throated hummingbird's heart beats up to 1200 times per minute (about 20 beats per second). Many birds possess a muscular pouch along the esophagus called a crop. The crop functions to both soften food and regulate its flow through the system by storing it temporarily. The size and shape of the crop is quite variable among the birds. Members
The Handbook of Australian Sea-birds into their habits, and the problem of their conservation. The second part (Section V) of the book summarises what is known to date of the different species of birds in our region. Where there are adequate data each bird is described under the heads: Field Characteristics and General Habits; Status in Australia; Migration; Voice; Display; Breeding; Enemies and Mortality; Breeding Distribution.” The Handbook of Australian Sea-birds The Handbook of Australian Sea-birds is a book published in 1971 by A.H. & A.W. Reed in Sydney. It was authored by Dominic Serventy, his brother Vincent Serventy, and John Warham. It is in