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.

In order to successfully colonise the urban environment, birds must be able tolerate pedestrian and vehicle proximity, because exhibiting a strong fleeing response each time that a harmless traffic stimulus is encountered would be maladaptive. We examined whether a native ‘urban adapter’, the Australian magpie (Cracticus tibicen), varied in its tolerance of human approach and a simulated vehicular traffic sound in urban Melbourne, Australia as a function of pedestrian or vehicular traffic volume in the local area. The flight initiation distance (FID) paradigm and presentation of a potentially startling sound stimulus (SSS) were used to measure the magpies’ boldness in areas with differing traffic volumes. Magpies in areas with relatively high pedestrian traffic volumes exhibited a shorter FID to, and retreated a shorter distance from, an approaching human than conspecifics experiencing relatively low volumes of pedestrian traffic. Magpies in areas with a relatively high vehicular traffic volume were less likely to flee from a SSS than conspecifics in areas with little or no vehicular traffic. Habituation to human disturbance and/or adjustment of anti-predator effort seem the most likely explanations for these disparities and suggest that magpies have considerable behavioural flexibility. The ability to tolerate high volumes of traffic and the associated noise allows magpies to use: (a) ecologically suitable habitat adjoining city roads with heavy vehicular traffic and (b) urban areas with many pedestrians and consequently much human food waste, which the birds exploit.

Comparative studies predicted or reported weaker or stronger positive relationships between nest size and body size both within and across avian species. Here we show that in relatively small nest-chambers, larger Great Tits (Parus major) build shallower nests than smaller Blue Tits (Cyanistes caeruleus). Our results from the Mediterranean region support findings from published studies that were conducted at more northerly latitudes (UK and Poland). Potential impacts of the local climate and predation risks on the species-specific expression of the size of fresh nests are discussed.

Communal nests often provide benefits, such as protection from predators and refuge from extreme temperatures, to the inhabitants of the nest. The benefits returned to individuals performing nest construction may not scale linearly with the amount of nest construction performed. If the returns on nest construction are non-linear, then recent theoretical studies suggest that selection for reproductive competition may destabilise the cooperative behaviours that maintain the communal nest. To investigate these questions, we measured the thermal benefits provided by sociable weaver (Philetairus socius) nests, and how those benefits scale at multiple nest sizes, including the point where zero investment in nest building returns no benefits. We find that the average temperature buffering provided by nest chambers is correlated with distance to the edge of the nest and that the benefits provided by nest construction are asymptotic. This suggests that cooperative nest construction will maintained at a lower level than if the benefits were linear.

Microsatellites are a valuable tool in the analysis of population genetic structure. Utilising microsatellite markers that were originally isolated from other species (cross-species amplification) can prove an efficient way, in terms of time and cost, to obtain markers for genetic studies. Here, 55 avian microsatellite primer pairs were tested for the cross-amplification in the Melodious Warbler ( Hippolais polyglotta). Thirty-five markers amplified, of which 22 were polymorphic, displaying two to nine alleles in the 15 individuals genotyped. The 35 markers which amplified in the Melodious Warbler were tested in its sister species the Icterine Warbler ( H. icterina). Twenty-four markers were amplified, 14 of which were polymorphic in the five H. icterina individuals genotyped. Thirteen loci were polymorphic in both species. The polymorphic loci identified are suitable for analysing the genetic population structure and assigning parentage.

The temporal variation of bird assemblages at three sites within a wetland of the Parana River was examined. The aim was to obtain an overview of the influence of spatial heterogeneity on communities in such a variable environment as the wetlands. We recorded 1,662 individuals belonging to 139 species from 40 families. There were no significant differences between sites in richness, abundance nor diversity. Species richness in the first year was greater than during the second year. Number of resident and migrant species decreased in the second year. Community composition differed between the two years of study and was significantly different among seasons. Species were grouped into 19 trophic guilds. In this study, number of species and their abundances were not significantly different among sites; there were differences in the composition of birds among sites. Thus, the structure of the environments influenced the composition of assemblages in different areas. Guild composition remained fairly constant between years and among seasons. Geomorphological and hydrological dynamics of the river produce a heterogeneous availability of habitats and resources that affect the composition of bird assemblages. Annual and seasonal changes in meteorological variables can lead to changes in the structure and/or composition of those assemblages.

Incubation in birds is energetically demanding and the energy invested to maintain egg temperature can influence the outcome of a reproductive event and therefore the lifetime reproductive success of individuals. It is reasonable that heat loss can be minimised by optimising the physical structure and location of the nest. I assessed the structural and thermal properties of nests across 36 species of Australian passerines, assessing variables against parent mass, egg and clutch size, once accounting for phylogenetic relationships. The surface area and volume of the nest cup increases with the surface area and volume of the clutch, as well as the size of the incubating parent. Sexual size dimorphism influences the mass and density of nests, while structural support for the parent and clutch is the primary factor driving nest thickness. A change in nest thickness with the combined mass of the parent and clutch has a direct influence on the conductance of nests, such that structurally adequate nests achieve a lower thermal conductance (higher insulation) than expected, as they increase in size. When exposed to wind or rain, the rate of heat loss from the nest increases, which is likely to have direct consequences on the energetics of the incubating parent. However, birds breeding in warm and wet conditions select materials for nest construction that have a high thermal conductivity to facilitate the nest drying process through rapid evaporation and reduce the overall cost of incubation. This provides confirmation that selecting a sheltered nest site and constructing an appropriate nest to minimise heat loss is important for avian reproductive success.

Nest parameters are most commonly measured only once during the nesting cycle. However, the condition of a nest is not constant but can substantially change from one nesting stage to the other, especially between incubation and nestling periods. These temporal changes may drive modifications in nest characteristics. We investigated the change in nest fresh mass between the early stage of incubation and shortly after the nestlings fledged and examined whether nest dry mass measured after the completion of the nesting cycle, which is commonly used in avian studies, is correlated with initial and final nest fresh mass in a small migratory passerine – the Pied Flycatcher. Nest fresh mass after the nestlings fledged constituted 180% of the initial fresh mass and the magnitude of mass increase was dependent on the number of fledglings and probably was partly associated with increasing water content in nesting material. Nest dry mass was strongly correlated with nest fresh mass measured both at the beginning of incubation and after the nestlings fledged, and also with the number of fledglings. Because in the Pied Flycatcher changes in the nest fresh mass are dependent on brood characteristics, in order to obtain the most reliable estimate of the initial nest fresh mass, we recommend weighing the nest shortly after its completion, taking care to make the measurement when the humidity of the habitat is rather low.