... Size 100,000 100,000 50,000 45 ,000 40 ,000 30,000 18,000 15,000 3,000 2,000 1,500 1,000 500 150 110 250 45 0 45 0 45 0 100 75 60 60 15 18 15 14 13 10 102 Biology of Marine Birds ranges are only now ... which shows actual results from two Black-legged Kittiwake colonies © 2002 by CRC Press LLC 94 4 .4. 3 A COLONY IS Biology of Marine Birds A SAFE PLACE Subadult birds visit their natal colony and other ... Fairweather and Coulson 1995) 4. 4 THEORIES OF THE FUNCTIONS AND ADVANTAGES OF COLONIAL BREEDING 4. 4.1 SHORTAGE OF NESTING SITES One of the earliest suggestions as to why some birds nest in colonies...