Trophic Niche and Feeding Strategy of the White Stork (Ciconia ciconia) during different Phases of the Breeding Season

Abstract

Assessing feeding conditions and variations of diet composition over the breeding season is of great help in the understanding of the ecological niche of species. In meeting this aim, the White Stork's (Ciconia ciconia) diet was studied based on the analysis of 87 regurgitation pellets collected from Batna (Northeast Algeria). A set of 2138 prey-items were identified and classified into 61 different prey-species belonging to seven classes, 13 orders, 29 families and 51 genera. The White Stork has a diverse diet (food niche breadth, FNB = 14.5, Shannon index H' = 4.4 bits), mainly composed of arthropods, of which 94% of prey-items are insects that represent 8% of total prey biomass. The White Stork constantly fed on the remains of chicken foraged from rubbish dumps (biomass = 68.74%) and small mammals (biomass = 14.41%) as these prey categories constitute a source of high energy, particularly during the period of chick rearing. GLMs applied for diet characteristics revealed a significant variation in numbers of prey individuals between breeding phenological stages. While variations of other diet parameters (biomass, species richness, FNB, H', H' max and evenness) were not statistically influenced by breeding phenology. All diet characteristics were significantly correlated with the period of chick development, which is the key period for breeding success; suggesting an increase in parental investment and feeding effort. Our findings suggest that the White Stork performs a balance in order to satisfy its food requirements by compensating reciprocally between intake of prey numbers and their biomass regardless of the phenological stage of reproduction.

Sexual differences in food preferences in the white stork: an experimental study

“…The general dietary composition of the studied white storks was similar to that determined in field conditions: mammals were taken in great numbers, followed by birds and fish (Pinowska and Pinowski 1989; Pinowski et al 1991; Antczak et al 2002; Kosicki 2010, 2012; Chenchouni et al 2015; Tobółka et al 2015; Chenchouni 2016). Amphibians, traditionally considered common prey for the white stork, contribute to its diet to a variable degree depending mainly on weather conditions (Schierer 1967; Pikulik et al 2001; Antczak et al 2002; Profus 2006; Kosicki et al 2006) but in experimental conditions were eaten rather rarely.…”

“…Thus, it is possible that the preferences of female white storks for avian prey might be an indication for fast supplementation of calcium and other nutrients which are more readily available from avian skeletons than from mammalian (Bilby and Widdowson 1971; Graveland and van Gijzen 1994; Poulini and Brigham 2001; Reynolds et al 2004). This may be an important strategy during spring (return from wintering ground and egg laying and incubation) which requires substantial amounts of microelements and energy (Walsberg 1983; Neger et al 2001; Reid et al 2002; Tinbergen and Williams 2002; Durant et al 2004; Neger 2006; Kitowski 2007; Djerdali et al 2008, 2016; Wuczyński 2012; Chenchouni et al 2015; Chenchouni 2016). Despite studied females did not undertake attempts to reproduce or lay eggs before or after the completion of the study, the general physiological processes in wild and captive birds, including white storks, are similar (Hall et al 1987; Herborn et al 2010).…”

“…The diet items offered to birds were chosen based on published data on the diet of the white stork in the wild (Cramp and Simmons 1988; Pinowska and Pinowski 1989; Pinowska et al 1991; Pinowski et al 1991; Mužinić and Rašajski 1992; Antczak et al 2002; Kosicki et al 2006; Chenchouni et al 2015; Orłowski et al 2016). The food was presented in shallow plastic containers, according to the procedures associated with a ‘cafeteria test’, at the same time every day, i.e.…”

“…However, the question of whether this species is characterised by sex-related food preferences has not been tested to date (Latus and Kujawa 2005; Djerdali et al 2008). Numerous authors researching the diet of the white stork or of closely related species such as the wood stork Mycteria americana have pointed out that these diets are dependent on climatic conditions, habitat type, prey densities and availability, suggesting a high degree of plasticity in food choice rather than a strong preference for any particular food type (Krapivny 1957; Pinowski et al 1991; Gonzalez 1997; Antczak et al 2002; Tryjanowski and Kuźniak 2002; Tryjanowski et al 2005; Tryjanowski and Hromada 2005; Zduniak 2005; Profus 2006; Kosicki et al 2006; Ciach and Kruszyk 2010; Chenchouni et al 2015; Chenchouni 2016; Orłowski et al 2016). These studies were done in field conditions, which preclude unambiguous inferences about food selectivity.…”

Rapid increase in numbers and change of land-use in two expanding Columbidae species (Columba palumbus and Streptopelia decaocto) in Algeria

“…The significant variation of flight directions over time is due to different uses of foraging habitats as the productivity of these habitats also changes over time. This may be related to the change in nutritional needs following phenological breeding stages, so the species change flight directions towards foraging habitats that match its feeding requirements [26].…”