The effects of landscape alteration on wildlife have drawn increasing attention from ecologists as landscapes have rapidly changed worldwide. Large-bodied birds are highly sensitive to habitat loss and fragmentation. We aimed to test two hypotheses concerning landscape-abundance relationships of male Wild Turkeys Meleagris gallopavo silvestris, the largest galliform in North America. The landscape fragmentation hypothesis posits that animal populations would decline linearly with habitat fragmentation, independent of the effects of habitat loss. The landscape composition hypothesis states habitat quantity, measured at spatial scales larger than the individual territory, would influence species abundance. Using the National Land Cover Database, we extracted the metrics of landscape fragmentation and composition at turkey annual dispersal (i.e., a buffer of 16-km radius) and annual home range (i.e., a buffer of 2.15-km radius) scales, respectively, for 28 wildlife management areas across Mississippi, USA. We used the mean annual number of harvested adult males per hunter day during annual spring hunting seasons (mid-March to mid-April) from 2001 to 2005 as a relative abundance index. Male Wild Turkey relative abundance increased with increasing fragmentation of hardwood forest (i.e., deciduous trees as the dominant form of vegetation) at both annual home range and dispersal scales, contrary to the prediction of the landscape fragmentation hypothesis. Male Wild Turkey abundance also increased with increasing landscape interspersion and juxtaposition index (i.e., an index of landscape spatial configuration) at the annual dispersal scale. We found nonlinear relationships between the proportion of hardwood forest and male turkey abundance, supporting the landscape composition hypothesis. Male turkey relative abundance peaked at 29% hardwood forest within the annual dispersal distance. Diverse landscapes are beneficial to Wild Turkeys at large spatial scales.

Partial mortality in broods of altricial passerines results from various reasons, including deficiency of resources, inadequate parental care, diseases and other external factors. In this study we test two hypotheses concerning the phenomenon of partial mortality in nestling altricial passerines: (1) non-adaptive starvation hypothesis based on the assumption that partial brood losses are caused by starvation and undernourishment and has no adaptive value, and (2) adaptive starvation hypothesis assuming that losses from starvation might be elements of an adaptive strategy of reducing surplus nestlings in broods that are over-large. To test the above hypotheses we divided broods of two tit species Great Tit Parus major and Blue Tit Cyanistes caeruleus into two categories: broods with incomplete, less than 100% fledging success and broods with complete 100% fledging success. Subsequently, we compared physiological performance of nestlings between brood categories using blood hemoglobin concentration. We predicted, that if non-adaptive starvation hypothesis was correct, in broods with complete fledging success nestlings should be in better condition. Alternatively, if the adaptive starvation hypothesis was correct, no such difference in nestling condition should occur. In accordance with our prediction, we found that for both species, broods of nestlings that attained 100% fledging success had a higher mean hemoglobin concentration than broods in which fledging success was less than 100%. This result strongly supports non-adaptive starvation hypothesis.

Nowadays the use of remote photography systems is very popular for diet assessment. Despite the popularity, there is a greater need for evaluation of these systems against traditional methods of diet assessment, such as direct visual observation. The diet of Lesser Kestrel nestlings and adult provisioning rate were assessed using cameras and direct observations at four nests with various brood sizes during the breeding season in 2013. The study was conducted in an intensively cultivated area that belongs to a Special Protected Area of the Natura 2000 network in central Greece. Diet composition (prey type and size) was not affected by the recording method, the sex of adults, the brood size, the period of the day or the age of nestlings. Tettigoniidae was the most frequent prey delivered by adults. Our results from both methods showed that males delivered more prey items than females, supporting the general consensus of reversed sexual dimorphism for the Lesser Kestrel. The provisioning rate was not significantly related to brood size, but it was affected by the method of observation, parent sex and the interaction of method and nestling age. According to the direct observations, provisioning rates increased as nestlings grew up, while they decreased based on camera information. Higher provisioning rates recorded in direct observations at later nestling stages, can be explained by higher food requirements of nestlings. The decrease in provisioning rate with nestling age was mostly affected by the camera function, as a result of digital limitations, nest type and Lesser Kestrels behavior.

Kleptoparasitism is a well-known foraging strategy used by many colonial seabirds. The expression of this behavior can reduce the cost of foraging during the breeding season and ultimately this can be reflected in physiological parameters. Here we analyzed the relationship between the trophic strategy of Common Terns Sterna hirundo and two hormones, that are known to be involved in decision-making during the reproductive cycle and foraging activities: corticosterone (CORT) and prolactin (PRL). The study was conducted during the breeding seasons 2012–2014 at the Banter See colony in northern Germany where individuals with different foraging strategies were identified and monitored since 2008. We studied the concentration of hormones in two groups of birds: kleptoparasitic individuals i.e. individuals who steal the food captured by another individual, and honest individuals i.e. individuals who obtain the food on their own. Blood samples were obtained during the mid-incubation period using a non-invasive technique. Both hormones showed no significant relationship to each other. CORT concentration was similar in both groups of birds. However, the concentration of PRL was higher in parasitic than honest individuals in 2014. In addition, CORT modelling indicated a year effect (higher CORT in 2013), and PRL modelling indicated a significant effect of year (higher PRL in 2012) and a significant interaction between year and the trophic strategy in 2014. The results show no clear relationship between the feeding strategy and studied corticosterone and prolactin levels.

Energy availability explains the spatial variation of species richness. However, in arctic to temperate regions species richness in birds shows also a seasonal pattern with high species numbers in summer and low numbers in winter. Is it possible to explain this pattern by high energy availability in summer and low availability in winter? The ‘energy availability hypothesis’ rests on a positive correlation between abundance and species richness. Using weekly counts along a transect in Northern Bavaria (S Germany), we found the expected seasonal annual as well as biannual cycles in species richness (108 species observed in total). In contrast, the number of individuals showed no clear seasonal cycle, but erratic fluctuations particularly in winter. Weather conditions had only small effects on the number of individuals and on species richness. Adding weather variables to analyses increased explained variance only by 1.5% to 10%. The energy availability hypothesis is not able to explain the seasonal variation of species richness in temperate regions. However, bird assemblages during winter consist of species able to feed on various resource types, in particular seeds produced during summer. These left-overs provide the resources for diet generalists to survive the winter.

Human-induced changes in the natural environment impact upon a wide variety of genetic processes at all levels of population structure. Insight into these processes is now achieved by analyses of genetic diversity allowing the past and present condition of populations to be assessed and compared. Given its severe fragmentation and small size, the population of the Capercaillie Tetrao urogallus in Poland can be regarded as especially prone to gene-pool alteration. Moreover, this is a region of Europe in which different genetic lineages of the Capercaillie may be present, ensuring that certain conservation decisions may be even more difficult than they otherwise would be. Bearing the above in mind, we decided to study polymorphism of the mitochondrial DNA Control Region (mtDNA CR) in remnant and extinct populations of the Capercaillie in Poland. The extinct population was represented by samples from birds hunted in the Lower Silesian Forest (SW Poland) between 1951–1962. We compared sequences obtained with data from the large, continuous population present in Russia and Scandinavia. Analysing 331 bp of mtDNA CR for 168 individuals, we identified 24 haplotypes, among which only 6 had not been reported previously in the species according to GenBank. Our data confirmed a previous suggestion regarding the genetic structure of the species in Poland, i.e. that birds from Augustów Forest (NE Poland) are related to Russian and Scandinavian populations, constituting a part of the lowland group within the boreal lineage. The Carpathian population is in turn confirmed as an independent genetic group within the boreal lineage, while specimens from the Solska Forest (SE Poland) prove to be highly differentiated from birds in other Polish populations; most likely because they derive from — or have been connected via gene flow with — birds present in the Balkans. Further genetic analysis is necessary to resolve this evolutionary relationship between Capercaillies from south-eastern Poland and those of the Balkans. Where practice is concerned, the overall advice is that three Conservation Units are to be recognised in Poland. In addition to those, the extinct population from the Lower Silesian Forest has been deemed part of the lowland group within the boreal lineage, albeit a distinctive one, given the possibility of gene exchange with Carpathian birds. We further suggest that some aspect of this extinct population's genetic diversity reflects an uncontrolled process of reintroduction taking place in the past.

Social monogamy with genetic polygamy is a frequent mating system in birds. In Passeriformes, extra-pair paternity (EPP) was reported in 86% of the studied species, with high variation in occurrence and frequency within and between species. In the highly diverse Neotropical region, the genetic mating system is known for only 26 bird species. We present the first molecular data on the genetic breeding system of the Ringed Warbling-finch Poospiza torquata, a socially monogamous species of the tanagers family (Thraupidae) that inhabits arid and semi-arid regions of South America. We obtained data from 92 nestlings belonging to 35 nests during three consecutive breeding seasons (2008–2011). Paternity assignments were made using five microsatellites developed for other bird species, and calculated using CERVUS v. 3.0. We found that extra-pair males sired 20.65% of the offspring in 42.86% of the broods. The EPP level in this species was found to be close to the average level in Thraupidae, with reported values ranging between 8–50% and 15–63% for nestlings and broods with EPP, respectively. This wide interspecific variation points to the ecological factors as being very important in facilitating EPP among Thraupidae species.

Patterns of bird nest orientation in dense forest interiors are relatively unknown. Using data collected in primeval temperate forests at the Białowieża National Park in Poland, we found that two arboreal nesting species, the Song Thrush Turdus philomelos and the Hawfinch Coccothraustes coccothraustes, located significantly more of their nests in the southern half of tree crowns than in the northern half. Nest orientation also depended on nest height: the higher Song Thrush and Hawfinch nests were in the crowns of trees, the stronger preference both species had for locating their nests toward the south. For the Song Thrush, tree species interacted with the date of clutch initiation to influence patterns of nest orientation: Song Thrushes located more of their nests on the ‘south-facing’ sides of live Norway Spruces Picea abies as the nesting season progressed. Spring temperature during the nest construction period affected Hawfinch nest orientation, with significantly more ‘south-facing’ nests during colder springs. The directional orientation patterns we observed may be viewed as a response of nesting birds to weather conditions during nest site selection and nest construction periods, when exposure to solar radiation could help regulate nest temperatures during cold mornings or days.

Unpredictable resources in seasonal environments may favour innovative individuals that efficiently explore and exploit such resources. We tested the hypothesis that potential intraspecific abundance is a more powerful predictor of detection of a novel food source than interspecific abundance and predation risk. The hypothesis was tested using latency of Great Tits Parus major to find bird-feeders in relation to the abundance of Great Tit and other birds, as well as cats recorded close to novel feeders in urban and rural habitats. Data were collected during winter 2013/2014 in eight cities and nearby rural areas across Poland. Generalized linear models, multimodel inference and hierarchical partitioning showed that the probability that Great Tits used a novel birdfeeder was positively correlated both with the number of Great Tits and all other tits combined in the vicinity of feeders. Latency in feeder usage was negatively related to the number of conspecifics, and it was less strongly negatively related to the number of other tits and the abundance of all other species. The effect of the number of other tits interacted with the environment; the number of tits positively correlated with latency in rural areas, while this relationship was negative in urban areas. Latency until arrival at a feeder was shorter for males than for females. The effect of cats at feeders on bird behaviour was statistically non-significant. Thus, latency until arrival at novel birdfeeders was predicted by local population size and abundance of other bird species, but not mammalian predators, and this relationship may be altered by the environment.

Woodpeckers play important ecological roles as excavators of tree cavities, many of which are subsequently used by other vertebrate species. Tree cavities may serve as either roosting or nesting sites, providing protection from external climatic elements and predation. Cavity entrances are hypothesized to be excavated in directions that allow for maintenance of microclimatic variables inside the cavity, or are alternatively linked to wood hardness of cavity-bearing trees, and are for those reasons often non-randomly oriented. It has been suggested that the mean direction of these cavity entrances vary across latitudes, from south-facing entrances at high latitudes to entrances facing east and west closer to the tropics. I show non-random distribution of the orientation of cavities excavated by at least one species of woodpecker i.e. Yellow-tufted Woodpecker Melanerpes cruentatus near Tena, Ecuador, and that entrances face predominantly towards the southeast. This study is a first step to gather ecological information on tree-cavity-nesting communities in this region, with the factors driving non-random orientation to be tested in future studies.

For seabirds, nest site features are an important factor that determines reproductive success. During three breeding seasons (2010–2012), we visited two coastal cliff colonies of Red-legged Cormorants Phalacrocorax gaimardi in the Ría Deseado, Argentina, and studied how nest site characteristics influenced their breeding success. We measured six physical characteristics at 46 nest sites, and we counted the number of fledglings produced each year from each nest (breeding success). We also related nest site temperature and wind exposure with nest site orientation. Breeding success was higher at nest sites with a broad base (greater capacity for holding young) and at nests that were less exposed to winds greater than 25 knots (46.25 km/h), which were sites with a north orientation. The lowest breeding success was observed in nest sites that were exposed to the strongest winds (i.e., sites with a south orientation). Strong winds often blow eggs and chicks away from the nests and increase opportunistic predation by gulls Larus sp. No significant relationship was found between nest site orientation and nest site temperature. Breeding success decreased with the distance to the nearest nest, which agrees with the idea that higher density of reproductive individuals reduces effectiveness of predators. Nest cover, distance from the top of the cliff, and distance from the tide line had no effect on breeding success at this study scale. Our results suggested that nest site characteristics that were related to protection against adverse weather conditions (e.g., strong winds) and avian predation, in combination with a suitable nest space, determined the breeding success of Red-legged Cormorants.