Groei en leeftijdsbepaling van nestjonge Sperwers Accipiter nisus

Nestling growth, expressed in maximum wing chord (flattened and straightened) and body mass, was studied in 25 nests in which hatching date was accurately recorded. Nests were visited, and chicks weighed and measured, every 4-5 days until the oldest chick was 23-24 days old. Sex-specific growth curves are provided using fitted growth equations (males in Fig. 1, females in Fig. 2; means and sample sizes in Appendix A). Estimates and standard errors of asymptote, growth constant, inflection point and r2 are summarised in Table 1. These data, and especially the growth curve for wing length, can be used to accurately estimate chick age up to 23-24 days old.