Growth rates of Ring Ouzel Turdus torquatus nestlings

Abstract

Breeding Ring Ouzels Turdus torquatus torquatus were studied during 1992–98 in upper Glen Esk, Angus, Scotland. Measurements of mass, wing length, tarsus length and tarsus diameter were taken from 163 nestlings of known age and graphs of these parameters plotted. Growth curves were plotted from the data and the growth constant k calculated. The growth constant for mass was greater than that for both wing and tarsus length. The calculated value of the growth constant for mass was lower than the previously published value for T t alpestris but higher than that for Blackbird T merula. Greater within-brood variability for mass was found in larger broods. There is virtually no published information on growth rates of Ring Ouzel nestlings and the data should prove a useful guide to ageing young in the nest. © 2003 British Trust for Ornithology.