The diet of the barn owl from three localities in Thessaly, Central Greece, was studied in the breeding and non breeding seasons over one year. A total of 420 pellets with 1.013 prey items were analyzed. Twelve small mammalian species were taken (94.9% by number and 96.1% by biomass), although Mus domesticus (26.3%), Crocidura spp. (25.3%) and Apodemus spp. (18.4%) were the main species predated by number. Rats (Rattus spp.), showed the highest frequency (11%) and biomass percentages observed to date in Greece, and their presence in the barn owl diet is also among the highest in the Mediterranean Europe. Birds (Passer spp. and Carduelis spp.) and insects (Acrididae) were also present (3.9% and 1.2%, respectively). Ecological niche values, seasonal and geographical differences were tested, the results pointing to the opportunistic feeding behavior of the barn owl in the croplands of central Greece.
Nest site preference of black stork nesting in the Dadia-Lefkimi-Soufli National Park, northeastern Greece was studied through the 2003 - 2004 field seasons. Seventeen nest-trees and their surroundings (0.1 ha circular plot centered at nest-tree) were described and compared to the characteristics of the same number of paired, randomly selected plots. Black storks usually nested in old pines, on branches at a mean distance 1.5 m from the trunk or against the trunk. Nest sites were located at slopes significantly steeper and significantly closer to small streams compared to random plots. The total tree density at nest sites was significantly lower and the mean canopy closure immediately adjacent to black stork nest trees was also significantly lower compared to that adjacent to the randomly selected trees. Nest sites had lower tree basal area than randomly selected sites, suggesting that the less wood volume sites were preferred for nesting by black storks in the study area.
Sibling competition leading to physiological stress and elevated allostatic load is driven by asymmetrical development and limited resources. To investigate these predictions, we studied broods of the lesser kestrel Falco naumanni, from a nest-box population in Armenio, Central Greece. For each nestling reared in nest-boxes, we noted the age (in days) since hatching, measured the wing chord length and body mass. We also clipped the central right rectrix for ptilochronology for subsequent analysis in the laboratory. We measured 206 nestlings from 61 broods (range 2-5 nestlings). In the case of nestlings < 18 days old (n = 198, 96.1% of all) we also measured the length of feathers. As a measure of body condition, we used the residuals of the linear regression for the relationship between wing chord length and body mass, while the growth bar width of feathers was used as a second, independent index of body size and allostatic load. A GLMM and information-theory criterion showed that both measures of body condition decreased incrementally from the first sibling to the most subordinate in the brood. Body condition of subordinate siblings was influenced by the number of siblings in the nest; i.e. the larger the brood size the greater the discrepancy in body condition between siblings. At the same time, we did not find any influence of sex on either measure of fitness. Thus, our results indirectly support the hypothesis that sibling competition may cause physiological developmental stress which is reflected in decreased body condition and increased allostatic load for younger nestlings.