Brood patches allow the transfer of heat to eggs for their successful embryonic development, and in many species determine egg temperature during incubation. We investigated brood patch development of Magellanic Penguins Spheniscus magellanicus in Isla Quiroga, Argentina, during 2012–2013. Here, we evaluate if brood patch development (in a narrow sense i.e. increase of the brood patch area and temperature measured with an electronic probe thermometer) varies according to laying date of the eggs, and with respect to adults' body condition and size, total clutch volume, and/or the sex of the adults. We found that brood patch temperature reaches its maximum when egg laying is finished, while brood patch area is fully developed starting from the end of the first quarter of the incubation period. The later the penguins started to breed the warmer the initial brood patches — when first egg is laid. Besides, the incubation period was shorter in penguins breeding late. Furthermore, adults in a good body condition had cooler initial brood patches than adults with poor body condition. In contrast, total clutch volume, body size index, and sex of the adults were not related to brood patch development. We conclude that initial brood patch temperature in Magellanic Penguins is associated with environmental factors, like laying date, and physiological attributes, like body condition.

Birds inhabiting urban areas have to deal with high levels of ambient noise. Some species show a certain song flexibility that enables them to reduce noise interferences in their communications. This vocal adjustment usually implies an increase in the minimum frequencies of songs. Since urban noise is mainly made up of low frequencies (about 2.5–3.5 kHz), song of species that sing at higher frequencies could be less susceptible to being masked by anthropogenic noise. This study explores whether such species also show any kind of adjustment to noisy environments. For this purpose, the spectral and temporal parameters (note duration, maximum and minimum frequency and diversity) of the song of the European Wren Troglodytes troglodytes were analysed in three different environments (urban, periurban and rural). To evaluate the impact of noise on the vocalizations, a specific acoustic descriptor of song variability was developed. Song variability increased along the urban noise gradient from rural to urban areas and the duration of notes decreased from rural to urban zones. Urban wrens developed more complex songs with higher frequencies and longer notes than their rural counterparts, whereas peri-urban birds occupied an intermediate position, although closer to urban ones in the length of notes. These changes could be associated with higher background noise levels, although other possible causes, such as the population density, could also explain them. Maximum frequencies were mostly outside the background noise range and differed among habitats, whereas lower frequencies unexpectedly did not differ among habitats. Our results suggest that differences in song parameters among species may lead to different mechanisms of vocal adjustment. Even in wrens, with high frequency vocalisation, interference with urban anthropogenic noise could show certain changes in their vocalizations.

Human activities may generate geometrical landscape (i.e. composed of rectilinear and repetitive landscape units) structures that can significantly influence the spatial distribution of birds. While bird distribution in various landscape types has been extensively studied, the role played by landscape configuration and composition in different facets of bird diversity remains unclear. Here, these two main components of landscape characteristics (i.e. configuration and composition) are disentangled and their relative influence on three different facets of bird assemblages: taxonomic and functional characteristics, and the presence of rare species, is tested. We chose four large coastal salinas of Western France as a relevant model of geometrical and human-dominated landscapes where each landscape unit can be easily identified and mapped. The landscape characteristics of these sites were mapped and quantified. Then, terrestrial breeding birds were sampled in 172 point-counts using a standardized protocol. 69 diurnal terrestrial bird species were detected and considered in analyses (waterbirds and owls excluded). Landscape composition was found to have a higher influence on bird communities than landscape configuration, which fits with the “landscape composition hypothesis”. More specifically, the most “extreme” landscapes — those with low terrestrial surface areas, low landscape richness and diversity, low cohesion, and very patchy landscapes with complex geometrical shapes — host the lowest bird taxonomic abundance, richness and diversity and functional richness, but are characterized by the presence of rare species (mainly wetland specialist species, e.g. Reed Bunting Emberiza schoeniclus and species with restricted ranges e.g. Bluethroat Luscinia svecica namnetum). Our results suggest that conservation plans in such geometrical and human-dominated habitats should not only focus on one aspect of landscape characteristics or one aspect of biological diversity but also consider the adverse effects of landscape characteristics on these different facets.

In partially migratory bird species, some individuals of a population migrate while others stay in the breeding area. Although Common Kestrels Falco tinnunculus are defined as partial migrants, their migratory strategies are still not well described. We investigated ringing and re-encounter data of Kestrels marked as nestlings between 1924 and 2011 in Germany. We defined four populations corresponding to the natural regions of Germany. Although both migratory and resident individuals were found independently of sex or age class at the time of recovery, in general, females and juveniles travelled larger distances than males and adults, respectively. We illustrated the initiation of migratory movements in contrast to dispersal by combining distances and directions in two levels (< 100 km and ≥ 100 km), showing that migration is initiated mostly in September/October, while in August movements seem to mostly reflect dispersal. The NAO Index as well as age class, region and re-encounter period (1950–1970, 1971–1990 or > 1990 as indicator of responses to climate change) of birds in autumn and winter were integrated into Generalized Linear Models. We found that in autumn and winter a tendency to migrate is primarily shown by juveniles and it was significantly higher in years before 1971 than in recent decades. In addition, a higher NAO Index in summer is linked with decreased proportion of birds re-encountered far (> 100 km) from their natal sites in winter, whereas a higher NAO Index in autumn is linked with increased proportion of high-distance re-encounters (> 100 km).

Knowledge about flyways, breeding and overwintering sites is important for conservation efforts, but little is known about migration patterns and population connectivity of declining European Turtle Doves Streptopelia turtur. EURING ring-recovery data were used to estimate directions and proportional usage of flyways. The timing of migration was compared along these routes and breeding origins of shot individuals were determined. Ring recoveries of Czech, Hungarian, British, German and French birds suggested three main flyways with westerly, central and easterly directions. The proportional usage was estimated by multinomial mark-recovery models. Major parts of French (62%), German (92%) and British (94%) Turtle Doves followed a western flyway. Czech birds used the central route (56%) and 55% of Hungarian birds followed the eastern flyway. Thus, a migratory divide between the Czech Republic and Germany could be suggested. The timing of migration showed a similar latitudinal pattern of migration along all flyways. Birds were at the breeding grounds in June and July and from September to April in their southernmost distribution ranges. Outward migration started in August. Return migration was still evident in May. The majority of reported hunted doves were from the 1960s and 1970s. High hunting numbers were present in September, April and May. France and Spain mainly shot birds from the UK and France. In Italy predominantly Italian birds were shot. Doves shot in Greece mostly came from the Czech Republic. Given the decreasing population numbers, large ringing numbers seem unlikely in the future. Thus, low recovery numbers in recent decades parallel both, the population decrease and a lower ringing activity.

The nesting preferences including both habitat and nest site characteristics of Syrian Woodpeckers in the agricultural landscape were assessed based on 69 nest sites described. Orchards were the preferred tree stand of the woodpecker, where 58% of its nests were located. The average diameter of tree in which the woodpeckers nested was much higher than the average trees available in territories (47.4 cm and 32.5 cm respectively). The condition of the nest trees was worse than the average trees present in the territories of the birds. Amongst Syrian Woodpecker nesting habitats, only orchards had a worse state of health compared to trees growing in groups, rows or forests. Apple trees Malus domestica with 43.5% of nest sites were also in worse health condition compared to willows Salix spp. (20.3% of nest sites), poplars Populus spp. and walnut trees Juglans regia. The average height of trees with nest holes was 11.3 m and the average height of nest hole placement was 4.2 m. The Syrian Woodpecker is an ecologically flexible species, but it requires trees with larger diameter trunks that are in poorer health as nest trees, such as, for example, apple trees or soft wood trees such as willows. The protection of non-forest tree stands dominated by these species and orchards, which are preferred by this bird, may be important to maintain the Syrian Woodpecker in the agricultural landscape.

The role of structural coloration, which is produced by the optical interactions among micro- and nanostructures in the feather barb or barbules, is still unclear in the context of sexual or social signaling, because the mechanism of color production is complex and the factors affecting it are not fully documented. We investigated whether structural colors represent class signals related to age, sex, and territory ownership in a social, sexually monochromatic species, the Eurasian Magpie Pica pica. We examined the reflectance spectra from white scapulars, bluish iridescent secondary and greenish iridescent tail plumage, as well as size of white scapular patch. Significant color differences between age classes were found in all measured plumage parts, with adults having plumage with higher color score, that is brighter, shorter wavelength-directed, and more saturated color, than young magpies. Color differences between males and females and between breeding adults (territorial owners) and non-breeding adults were only detected in the tail plumage. Size of white scapular patch did not differ between age and sex classes. Color differences among individuals belonging to different social classes may lessen agonistic confrontations. Sex differences in coloration may enable prompt sex recognition and thus facilitate pair formation. Higher tail color scores of adults, particularly males, support previous suggestions that the tail characteristics of avian species with relatively long tails represent a visual signal of the bearer's quality.

During 2008–2011, nine juvenile Saker Falcon Falco cherrug females were tagged with satellite transmitters in Slovakia. Satellite telemetry provided new insights into the juveniles' movements. In this study we present the use of temporary settlement areas (TSAs) during the movement of the tracked juveniles. We characterized natal areas (NAs, the first TSA in the life cycle of juvenile, restricted to the nest) and TSAs as areas where the distance between the all-night perches did not exceed ten kilometres and where a particular bird spent at least five consecutive days. In these areas 3 types of polygons were identified in relationship to the area of use — a home range (95% kernel polygons), a core area (50% kernel polygons) and an overall used area (100% minimum convex polygons). The overall used areas were highly variable and probably influenced by exploratory flights, when sakers fly out of their home ranges and come back at night. Habitat preference was then analysed in the TSAs for a better understand of juvenile habitat requirements. For habitat preference a CORINE raster image (version 13/2006) with a resolution of 100 × 100 m was used. In the TSAs 14 habitat categories were recorded, but for statistical analysis only 8 habitat categories were used. Conservation status of the NAs and TSAs was also described. Arable land represented the dominant habitat category in the TSAs (mean 67.64% for overall used areas, and 80.94% for core areas). A significant difference was found in the habitat structure of the overall used areas, the home ranges and the core areas. All of the tracked Saker Falcons preferred arable land, while avoiding two habitat categories — forests and scrub and/or herbaceous vegetation associations. The number of days spent in the TSAs (9–139 days, mean = 46.7 days) and in the NAs (36–134 days, mean = 62.3 days) varied by different individuals. Most of the NAs and TSAs are at least partially covered by protected areas, only four areas had no conservation status.

Woodpeckers feed primarily on insects, larvae and other arthropods; however, several members of this family include plant products in their diets, such as sap. Among them, the genera Sphyrapicus and Melanerpes include the most species that specialize in sap consumption. In semiarid forests of Argentina, sap is an important food item in the diet of the White-fronted Woodpecker, Melanerpes cactorum. The aim of this study is to investigate why White-fronted Woodpeckers only consume sap from certain plants while avoiding other available plants of the same species and explore seasonality of their plant selection. We expected that combinations of plant traits (i.e. sugars concentration of sap, sap flow intensity, plant size, plant health and plant microhabitat), rather than one particular trait, determine which tree they select for sap feeding in different seasons. We examined five plant species: Sarcotoxicum salicifolium, Prosopis ruscifolia, Ziziphus mistol, Aspidosperma quebracho-blanco and Stetsonia coryne that were used most frequently for sap consumption and were consumed in all seasons by ten groups of White-fronted Woodpecker in semiarid Chaco, Argentina. Plants selected by White-fronted Woodpeckers for sap consumption were mainly larger plants that yield high sugar concentration. Of the plant species we studied, individual plant selection in all seasons was more evident in those plant species that constitute an important part of their diet (i.e. Prosopis ruscifolia and Stetsonia coryne). The selection of plants offering a greater reward in sap quality strongly suggests that the White-fronted Woodpecker maximizes food energy intake as a response to the seasonality that characterizes semiarid climates of temperate regions and conditions of food resources availability. Our results show that large trees are selected as sap trees by White-fronted Woodpecker, therefore, we recommend activities that promote retention of large trees in Chaco region.

The size and shape of the nest are species-specific characteristics that are often associated with environmental factors at the time of breeding. Nests are expected to be larger or thicker in colder environments, although the relationships between nest design and weather differ between species. Here we present the results of an analysis of the external height of the nest wall in Paridae that accepted small standardized nesting boxes for breeding. The study populations were monitored in a relatively cold Mediterranean study area. We found that Coal Tits Periparus ater built higher external nest walls than Great Tits Parus major or Blue Tits Cyanistes caeruleus, after controlling for the first-egg date and clutch size which are assumed to reflect aspects of the quality of the nest builders. Our measures of nest size were not closely associated with the average ambient temperature, but nest walls tended to be shallower when there was more rain. Nest-shape asymmetry, as reflected in the difference in the external height of the nest measured closest to and farthest from the nest-chamber entrance, was observed in all three species, but the average asymmetry was highest in Coal Tits. In asymmetric nests, more nest material was added to the side that was closest to the front wall considered to be the coldest and least protected against harsh weather. Thus, nest size characteristics differ between three ecologically similar species inhabiting the same cavity type in the same coniferous woodland habitat, which would imply that different species do not respond in the same way to the same set of environmental factors.

The rate of telomere loss is increasingly being used as a marker of biological aging, organismal senescence, and survival probability. These protective ends of chromosomes act to protect coding DNA during replication and by buffering against degradation from reactive oxygen species (ROS). In many organisms, telomere loss has been linked to increased levels of metabolism, biological stress and disease. Here we validate a medium-throughput and reliable method to measure relative telomere length in Sand Martins Riparia riparia. We performed the qPCR assay on a population of variously aged individuals from eastern Hungary. We detected a significant negative relationship between relative telomere length and age and observed a clear drop in telomere length in older age classes (> 4 years) but no relationship with gender or body mass. Our results in this cross-sectional study support findings in other passerine species that report a lack of long telomeres in older individuals. The method that we describe will allow longitudinal studies of Sand Martin individuals in wild populations to track telomere dynamics related to various life history characteristics and individual health.