Replacement and growth of primary feathers in captive rock pigeons, Columba livia (Aves: Columbidae)

the replacement and growth of 311 primary feathers of eight captive male rock pigeons, columba livia gmelin, 1789 were monitored daily. feather replacement was recorded in all months, but the primaries 1 to 5 (innermost primaries) were replaced mostly from september to december, whereas the primaries 6 to 10 (outermost primaries) were more frequently replaced from january to august. each primary was held in plumage from six to fifteen months, but the lifetime of the outer feathers was longer than that of the inner feathers. a new primary emerges two or three days after its predecessor has been dropped, but the primaries replacing the feathers accidentally lost during bird handling emerge only after about eight days. the average growth period of a primary ranged from 21 to 37 days, with the larger and outermost feathers exhibiting a longer growth period. a constant average growth rate of 4 to 5 mm/day was found for all primaries until the last two days of growth, when the growth rate of the feathers became progressively slower. bilateral symmetry in the primary replacement, when the same feather is replaced simultaneously in both wings, was not significant (22.2%) in the birds monitored in this study.