Birds

Birds

Birds (class Aves) are a group of endothermic vertebrates, characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines. Collision with wind turbine blades can kill birds, though the impact of individual deaths on the greater population varies greatly based on species. Reserach is exploring mitigation such as operation limitations, siting location, and lighting selection. Bird collisions with offshore wind turbines present the additional challenge of being unable to count bodies to determine the scale of mortality. Marine energy poses some threat to diving birds colliding with tidal turbines, or birds colliding with floating wave devices during adverse weather conditions. Birds are classified in the following categories:

• Ground-Nesting Birds
• Passerines
• Raptors
• Seabirds
• Shorebirds
• Waterfowl

_{Photo Credit: "Birds in sunset over water" by U.S. Fish and Wildlife Service}