Factors affecting growth parameters of White Stork nestlings in eastern Algeria

Abstract

International audienceSurvival 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

Kind to kin: weak interference competition among white stork Ciconia ciconia broodmates

“…According to Sasvári et al (1999a), seniors in nests where some broodmates had died attained larger asymptotic masses. This general result can be considered representative of other white stork populations on the basis of similarities in patterns of asynchronous hatching and size asymmetries (Tortosa 1992, Aguirre and Vergara 2007, Djerdali et al 2008a, nestling diet (Tsachalidis and Goutner 2002, Kosicki et al 2006, Cheriak et al 2014), rates of parental provisioning (Schüz 1943, Haverschmidt 1949, Sasvári et al 1999b, postnatal growth (Tortosa and Castro 2003, Tsachalidis et al 2005, Benharzallah et al 2015 and food distribution according to nestling rank (Sasvári et al 1999a). Broodmate competition is dependent on food availability to some degree (Drummond 2001b).…”

“…Summarizing, white stork nestlings competed for food by purely scramble mechanisms (eating speed) and virtually lacked behavioural mechanisms (aggressive dominance or physical interference) of interference competition. In the absence of food monopolization by seniors, scramble competition may be a sufficient explanation for differential patterns of growth (Benharzallah et al ) and share of food mass (Sasvári et al ) according to nestling rank. Consistent with this scenario of mild sibling rivalry, and contrary to species showing overt interference or aggressive competition, white stork nestlings showed no differences in glucocorticoid levels associated with brood hierarchy, and stress hormone levels were similar among two‐ and three‐chick broods (Blas et al , Corbel and Groscolas ).…”

“…Chicks fledge between 70 and 90 d (Redondo et al , Corbel and Groscolas ), becoming nutritionally independent shortly afterwards. White stork parents make optimistic decisions by laying larger clutches in response to food abundance during the pre‐laying period (Tryjanowski et al , Djerdali et al ) but seldom rear as many fledglings as eggs hatched (Schüz , Haverschmidt ), larger clutches suffering from higher rates of nestling mortality (Massemin‐Challet et al , Benharzallah et al ). White stork broods hatch asynchronously.…”

“…Brood asymmetries in size peak between the second and the fourth week of age (Aguirre and Vergara 2007) and decrease thereafter, both at nests with and without partial-brood losses (Tortosa 1992, Djerdali et al 2008a). Last-hatched nestlings eat a smaller share of food than their older nestmates (Sasvári et al 1999a), grow more slowly, attain lower asymptotic body masses (Tortosa and Redondo 1992, Djerdali et al 2008a, Benharzallah et al 2015 and suffer from higher mortality rates (Tortosa and Redondo 1992, Djerdali et al 2008a, Benharzallah et al 2015. Brood reduction (i.e.…”

Factors affecting fledgling output of great tits, Parus major, in the long term

“…In this long-term approach, we did not find other significant predictors of the number of fledglings produced per nest in the studied population, although other predictors are likely relevant in certain years, depending on environmental conditions. Several studies have analyzed the importance of brood size for nestling growth and survival (Groves, 1984;Coulson & Porter, 1985;Burness et al, 2000;Benharzallah et al, 2015), although its effect, either positive or negative, is dependent on parental quality and resource availability (Gebhardt-Henrich & Richner, 1998). Taking care of large broods is energetically demanding, forcing parents to adjust clutch sizes based on their ability to rear the resulting chicks (Lack, 1947;Murphy & Haukioja, 1986;Wellicome et al, 2013).…”