Factors affecting growth parameters of White Stork nestlings in eastern Algeria

Abstract

Survival and reproduction of young can be affected by growth parameters. It is thus important to estimate intraspecific growth rate variability and environmental factors affecting growth to better understand the dynamics of populations and the potential impacts of environmental changes. Growth parameters of White Stork (Ciconia ciconia) nestlings were estimated in eastern Algeria, in the southern part of the species’ range. A total of 2,756 measurements of 65 nestlings from 18 nests were taken for body mass, and tarsus, wing and bill lengths. Individual growth data were used to investigate the effects of nest occupation date, laying and hatching dates, clutch size, number of hatchlings, productivity, hatching order, and brood reduction on nestling growth patterns. Body mass and bill length growth rates were lower in the studied population than in a more northerly White Stork population. This supports the hypothesis of a geographic variation in intraspecific growth parameters. Chicks from nests occupied early reached higher asymptotic body mass but tended to grow more slowly. However, chicks from late arriving birds compensated for the difference in body mass and wing length by higher growth rates. Wing length was significantly affected by asynchrony and hatching order. Last hatched chicks had larger asymptotic wing lengths, lower wing growth rates and longer growth periods. Wings of nestlings from highly asynchronous broods grew faster but took more time to attain the inflection point. Brood reduction had a negative effect on nestling bill length at hatching. Chicks from nests with little brood reduction had a longer bill at hatching than nestlings from nests with high brood reduction.