P 2 Pigeons , Domestication of 3

8 Domesticated from the rock pigeon (Columba 9 livia), the domestic pigeon is an Old World 10 pigeon that, along with over 300 other pigeon 11 and dove species, comprises the family 12 Columbidae, in the order Columbiformes. 13 Although fossil evidence suggests that rock 14 pigeons evolved in Southern Asia, today the nat15 ural habitats of the wild rock pigeon are open and 16 semi-open environments across Europe, North 17 Africa, and Western Asia, with a preference for 18 cliffs and rock ledges for breeding. Domestic 19 pigeons, however, and their feral descendants 20 have spread across all permanently inhabited 21 regions of the world. 22 Pigeons exhibit variations in more traits than 23 any other bird species (Price 2002). Although first 24 domesticated as a source of food, the later spread 25 of the chicken diminished their importance and 26 thus most domestication traits present in modern 27 birds were explicitly selected for exhibition, or 28 to improve racing speed and homing ability. As 29 a result, the different breeds show dramatic 30 variations in craniofacial structures, color and 31 pattern of plumage pigmentation, feather place32 ment and structure, number and size of axial and 33 appendicular skeletal elements, vocalizations, 34 and flight behaviors (Figs. 1 and 2). This variation 35 is so great that Charles Darwin, the father of 36 modern evolutionary thought, noted that based 37 on morphology alone, a taxonomist might be 38 tempted to classify different breeds as completely 39 different genera (Darwin 1868). Despite their 40 remarkable divergence, pigeon breeds are so 41 obviously unified in their descent from a single 42 ancestral species, that Darwin used them as a key 43 example to illustrate his ground-breaking ideas 44 about natural selection. In particular, he saw 45 pigeons as a striking exemplar of how continual 46 selection can lead to significant, and rapid, mor47 phological and behavioral variations from 48 a single ancestral type (Darwin 1859). 49 Although pigeons are among the earliest 50 domestic birds and one of the earliest domestic 51 animals (Hansell 1998), relatively little is known 52 about their initial domestication. The rock pigeon 53 today consists of many subspecies spread across 54 Eurasia and North Africa, but exactly which sub55 species was the ancestor of domestics, when, 56 where, and how many times domestication 57 occurred, and how domestics spread over the 58 majority of their history are largely unknown. 59 Most of the available information comes from 60 written accounts rather than archaeological 61 remains, probably due to both the problem of 62 morphologically discriminating between wild 63 rock pigeons and the earliest ferals and domestic 64 strains, and their relatively fragile bones, which 65 could bias against long-term survival in the 66 archaeological record.