Factors affecting growth parameters of White Stork nestlings in eastern Algeria

International audience

Inglés. Survival and reproduction of young can be affectedby growth parameters. It is thus important to estimateintraspecific growth rate variability andenvironmental factors affecting growth to better understandthe dynamics of populations and the potential impacts ofenvironmental changes. Growth parameters of White Stork(Ciconia ciconia) nestlings were estimated in eastern Algeria,in the southern part of the species’ range. A total of2,756 measurements of 65 nestlings from 18 nests weretaken for body mass, and tarsus, wing and bill lengths.Individual growth data were used to investigate the effectsof nest occupation date, laying and hatching dates, clutchsize, number of hatchlings, productivity, hatching order,and brood reduction on nestling growth patterns. Bodymass and bill length growth rates were lower in the studiedpopulation than in a more northerly White Stork population.This supports the hypothesis of a geographic variationin intraspecific growth parameters. Chicks from nests occupiedearly reached higher asymptotic body mass buttended to grow more slowly. However, chicks from latearriving birds compensated for the difference in body mass and wing length by higher growth rates. Wing length wassignificantly affected by asynchrony and hatching order.Last hatched chicks had larger asymptotic wing lengths,lower wing growth rates and longer growth periods. Wingsof nestlings from highly asynchronous broods grew fasterbut took more time to attain the inflection point. Broodreduction had a negative effect on nestling bill length athatching. Chicks from nests with little brood reduction hada longer bill at hatching than nestlings from nests with highbrood reduction.