Growth and development of chicks of two species of partridge: the grey partridge (Perdix perdix) and the chukar (Alectoris chukar).

1. In two partridge species, the grey partridge (Perdix perdix) and chukar (Alectoris chukar), from hatching up to 120 d, the growth rate and development of body mass, wing, tarsus, and bill length were measured and fitted by Gompertz equations. 2. As a typical precocial species, partridges hatched with relatively well developed legs and bills, and wing growth followed a gradual development of thermoregulation. 3. Gompertz growth constants for body mass growth were 0·039 and 0·038 for grey partridges and chukars, respectively. 4. The allometric relationship between tarsus length and body mass followed a geometric similarity (1/3 power) in both grey partridges and chukars.