Recent studies showed that climate changes shape species distribution and could cause range shifts in the flyway level of the species. Here, we demonstrated changes in species habitat selection as a response to weather severity in twelve most abundant wintering waterbird species with prevailing increase in numbers during three investigated periods (1972–1978, 1987–1993 and 2003–2009). We used wintering waterbird counts from 93 sites throughout the Czech Republic from mid-January term as the coldest period of winter when the effect of thermoregulation on wintering waterbirds distribution is most apparent. We recorded no significant changes in weather severity in three investigated periods in our study area, and hence we considered the effect of preference of cold weather refuge sites, i.e. habitats which can reduce negative effect of cold weather (running waters, urban area and extensive water surface area). We found prevailing effect of weather severity in the first period what may show thermoregulatory effects being expressed by weather severity on species habitat selection in the next period in six of the twelve investigated species (Mute Swan Cygnus olor, Common Pochard Aythya ferina, Tufted Duck Aythya fuligula, Little Grebe Tachybaptus ruficollis, Common Moorhen Gallinula chloropus and Common Coot Fulica atra). In the face of recent climate change and in spite of the increasing importance of wetlands in the Czech Republic for wintering waterbirds, the suitability of these sites for wintering is likely temperature-dependent. Thus, the preference of cold weather refuges reducing the effect of winter harshness becomes important in individual species.

Body condition of nestlings can influence their future survival. Here, we used data obtained from a colourringing program of Yellow-legged Gull Larus michahellis in two colonies from northern Iberia to quantify the relative importance of pre-fledging body size and mass on post-fledging juvenile survival. Chicks were ringed with colour-rings at their colony in June/July when they were almost ready to fledge, and, thereafter, sighting data of these birds were collected over a period of one year and analysed with Cormack-Jolly-Seber capture-recapture models. The Yellowlegged Gull in the region is resident, so sighting data were mostly collected within an area close to natal colonies, where the field effort was intensive. Monthly survival from August onwards was higher than from ringing date to August (0.59± 0.06 SE), reaching model averaged values of 0.91 ± 0.03 and 0.98 ± 0.03 for the two colonies analysed. Moreover, condition of chicks (measured as residual body mass and body size) before fledging had a positive effect on survival from ringing date to August, but not from August onwards, when survival was strongly affected by the colony of origin.

The timing of breeding and nest location in colonial birds may have fitness consequences. In particular, it has been demonstrated that peripheral breeders perform less well than core breeders. To determine whether environmental factors such as date of breeding and nest position influence reproductive success, we studied the breeding ecology of a large colony of White Stork Ciconia ciconia at Dréan, northeast Algeria, during 2011 and 2012. Mean egg-laying dates varied significantly between years and differed between core and peripheral nests with more precocious laying occurring in the center. Egg-laying in larger nests started earlier than in smaller ones in the core area but neither nest size nor nest position along the core-periphery gradient had any influence on studied breeding parameters i.e. clutch size, hatching success and chick productivity. There was no yearly difference in clutch size which averaged 4.7 ± 0.7 eggs (N = 156 clutches). Mean chick productivity was higher in 2012 (2.85 ± 1.21 chicks) than in 2011 (2.29 ± 2.28 chicks) and was marginally associated with egg-laying date. In contrast, nesting success declined with delayed onset of breeding. Results suggest that a low predation rate, abundant resources and a possible trade-off between fitness components may confound adaptive breeding-habitat selection in White Stork.

Monocultures of even-aged trees in short rotation are a forest system of low ecological complexity that has been described as unsuitable for the establishment of stable populations of forest birds. However, key habitat quality cues could make them attractive to forest specialists. This paper assesses the suitability of poplar plantations in the northeast of the Iberian Peninsula for a forest specialist, the Lesser Spotted Woodpecker Dendrocopos minor. Poplar stands occupy a small area of an agroforestry mosaic landscape where semi-natural Mediterranean woodland is predominant. Population size, nesting success, home ranges and habitat selection were studied by radio-tracking and monitoring during the breeding season and the winter. Poplar plantations were preferentially selected for breeding and foraging in the spring and the winter. Home ranges in the breeding season and the winter (32.4 and 438.5 ha, respectively) were similar to those observed in semi-natural woodlands that have been studied in Europe. However, population density (0.25 territories/100 ha) was lower than that described in most European semi-natural woodlands. Nesting success was low (0.54), due to strong competition with other cavity nesters, predation of nests by the Greater Spotted Woodpecker, and loss of one of the adults. Fifty per cent of the foraging activity during the breeding season took place in an area of 180 metres around the nest. The amount of standing dead wood in poplar stands was much higher than in the surrounding habitats and source areas. The moderate breeding success and the high rate of adult predation may suggest that poplar plantations act as an ecological trap, in which standing dead wood may be a habitat quality cue that attracts birds to this non-ideal habitat. Poplar plantations become even less suitable when most of the available habitat is felled at the same time. Suitable planning of poplar plantation rotations and recovery of riparian forest is the best way to ensure the survival of Lesser Spotted Woodpecker populations in the long term.

In recent decades, the intensification of agricultural practices in olive orchards, including intensive use of agrochemicals, along with the absence of natural herb layer, has led to a decline in songbird communities. Increased nest predation has been suggested as another important factor in the decline of farmland birds. High abundances of alternative prey species, such as European Rabbits Oryctolagus cuniculus may attract generalist predators, which may increase predation rates on bird nests, a phenomenon known as hyperpredation. In this work, we evaluate artificial nest predation in intensively farmed olive orchards, using quail eggs (one plaster and two natural eggs in each nest) placed on the ground (97 nests) and on trees (106 nests). 53.7% of nests (109 out of 203) were predated; 51 of these nests had at least one egg with signs of predation and in 58 nests all eggs were predated. Nests placed on the ground (61%) were predated more frequently than those on trees (46%). Rabbit abundance was identified as one of the main factors increasing the probabilities of a nest being predated. Despite lower rates of nest predation in areas with low rabbit abundance, we found a higher diversity of nest predators, such as Mustela nivalis, Mustela putorius, Martes foina or Erinaceus europaeus in these areas. This study suggests that conservation efforts aimed at increasing the breeding success of farmland birds should avoid areas with high abundance of rabbits owing to the phenomenon of hyperpredation.

In recent decades, agricultural intensification and landscape simplification have dramatically affected farmland biodiversity. To reduce this trend, agri-environmental schemes (AES) of the Common Agricultural Policy (CAP) were launched in the European Union in the early 1990s. Since then an effort has been made to asses the effectiveness of these measures, but, in the Mediterranean region, where olive groves are among the predominant crops, the effectiveness of AESs to maintain farmland biodiversity remains poorly evaluated. In conventional olive farming, the only AES now in practice are the implementation of herbaceous, non-crop vegetation within crops (i.e. ground covers) aimed at preventing soil erosion, and the maintenance of hedges. These practices, when applied separately, can increase structural complexity, likely benefitting farmland biodiversity at different spatial scales; however, little is known about the potential synergistic effects when these measures are applied in combination in Mediterranean agroecosystems. This study assessed the combined effects of herbaceous ground cover and hedges on passerine communities of olive groves over a 4-yr period. Hedges, and to a lesser extent ground covers, efficiently increased the abundance and richness of passerine communities of olive groves, particularly that of insectivorous birds, but the effects of both measures were independent of each other. Hedges were particularly relevant to the richness and abundance of passerine communities, especially at distances up to 50 m. Therefore, we suggest that management should promote the creation of a hedge network embedded in the olive grove matrix, for example by promoting or maintaining hedgerows located between properties. This study underscores the important role of increasing structural complexity in Mediterranean perennial agroecosystems through the implementation of ground covers and maintaining hedges, to preserve farmland passerine communities, and encourages the use of these agri-environmental measures as a tool in landscape planning and conservation.

The western European populations of Northern Wheatear Oenanthe oenanthe have halved over the past two decades. In this context of increasingly fragmented populations, a key issue is to understand the role of immigration in the maintenance of remnant populations. We characterized the local survival, fecundity, recruitment and immigration rates of a small, geographically isolated, coastal French population during a period of population stability, while the regional population was rapidly decreasing (1991–1999). Annual local adult and juvenile survival rates were estimated with capture-resighting data at, respectively, 0.463 ± 0.052 (n = 157 adults) and 0.215 ± 0.054 (n = 363 nestlings). Only 2.1 immigrants joined the population per year (7.3% of all recruits). This annual immigration rate (0.039) is lower than all 14 available estimates for small to medium-sized birds. The local population growth rate depended equally on all demographic parameters, apart from a minor influence of the immigration rate. Within-site breeding dispersal distances were low, and differed between sexes (78 ± 49 m for males, 259 ± 274 m for females). Juvenile and adult survival rates appeared lower than for populations of wheatears settled in high quality habitats, but this deficiency was compensated by high fecundity and the 2 annual immigrants. The small population size (22–27 pairs), extremely low immigration, and strong dependence on local recruits suggest that this population was demographically isolated on a patch of moderate habitat quality, with no chance of rescue by immigration in case of stochastic event. Indeed, this population went extinct in the 2000′s, after a disturbance of unknown origin.

Amount and quality of resources may be variable and generally poor in habitats of marginal avian populations living at the edge of species breeding range. We studied variation in egg traits (length, breadth, volume and shape) in three populations of the African Blue Tit Cyanistes caeruleus ultramarinus inhabiting degraded habitats in highlands of Algerian Saharan Atlas at mean altitudes 1328–1437 m a.s.l. We found high within-clutch repeatability of all the egg traits studied. As theoretically expected in peripheral parts of the species geographic range, there was considerable variation in egg-size traits among the study populations, with eggs being distinctly smaller and more elongated at a site characterised by most human-modified habitat composed of maquis scrubland with rare Pistacia trees. Egg length and shape tended to be affected by the altitude of nest site and by clutch size, but not laying date. We found some effects of egg traits on hatching and fledging success, suggesting that fitness advantage of egg sizes is dependent of egg shape. We conclude that the above patterns of variation in egg size and shape of the African Blue Tit populations have influence of fitness. Our finding of considerable variation in egg traits between separate peripheral populations confirms the theoretical expectation and seems to be a novel result.

Over decades, several hypotheses for sex allocation have been proposed and tested repeatedly. However, many studies have shown inconsistent results among species, populations, and study years. We investigated sex ratio patterns in a population of Japanese Tit Parus minor, which is closely related to the Great Tit Parus major. In this fouryear study, a total of 1500 offspring from 191 nests were sexed. We found that the proportion of male offspring in each brood was negatively related to laying date and clutch size only in the first clutches. This corresponds to our prediction that in sexually dimorphic Japanese Tits, females may control sex ratio by adjusting clutch size or the timing of laying to reduce costs of rearing. However, this relationship did not appear in later clutches, indicating that manipulation of sex ratios occurred only in part of the season. Parental quality was not related to sex ratio in either first or later clutches. Our results suggest that female Japanese Tits may control the sex ratio to balance reproductive effort and self-maintenance rather than to raise the offspring fitness benefits in relation to the quality of parents, and that they use a different sex allocation strategy between first and later clutches.

Populations of House and Tree Sparrows have rapidly declined in various breeding habitats throughout their European distribution range; however, the strongest decline was recorded within urban environments. In our study we investigated fine-scale distribution, population densities and habitat selection of both sparrow species within a 200 × 200 m squares in a medium sized city (České Budějovice, Czech Republic) during the breeding season. The total population density of House and Tree Sparrow was 11.7 and 2.8 individuals/10 ha; however the densities of both sparrow species markedly differed among various urban units. The highest density of House Sparrow was recorded in residential areas (33.3 ind./10 ha) and Tree Sparrows were mostly found in garden colonies (10.3 ind./10 ha). After removing spatial effects, we found that numbers of both sparrows were negatively correlated with area of artificial surfaces (e.g. pavements, streets, railway networks or parking spaces) and positively correlated with area of city green. Built-up area did not affect numbers of House Sparrow, but there was a slight negative relationship with Tree Sparrow numbers. However, maximum numbers per square for both species were found in the areas where city green represented ca 50 % of all habitats. This suggests that mix of built-up areas and city green is more important for sparrow numbers than each habitat per se. Comparison of use/availability for studied habitat reveals that both sparrow species clearly avoided artificial surfaces. House Sparrow showed preference for built-up areas and Tree Sparrow showed similar preference for built-up areas and city green. Different habitat selection can be explained by a combination of different requirements for nest sites together with the nutritional needs of sparrows during the breeding season. The majority of nest sites were located in artificial structures such as roof tiles (80% for House Sparrow and 50% for Tree Sparrow), followed by nests located in crevices and holes on buildings. Both sparrows nested in older buildings: 92% of House Sparrow and 85% of Tree Sparrow nests were situated in buildings older than 30 years, i.e. built before the 1980s.

Anthropogenic noise, a consequence of expanding infrastructure and industry in ecosystems, is a serious and ubiquitous threat, which can significantly modify the behaviour and certain population parameters in animals. Birds are particularly vulnerable in this respect, given that they communicate mostly vocally in dense habitats. In the winter time traffic noise can modify distribution of birds by masking of their alarm and contact calls. Additionally seasonal variation in avian auditory can modified birds responses to traffic noise during winter. The present paper reports the results of an investigation into the influence of a busy road (annual average 6673 motor vehicles per day) and traffic noise on woodland birds in winter. To our knowledge this study is the first to assess the effect of road noise on woodland birds during winter. We counted birds using the point—count method at 36 survey stations located in the forest at various distances from the road. At each such station we assessed selected habitat parameters, the distance from the road and the noise intensity level. We recorded a total of 454 birds belonging to 19 species. The mean noise intensity during the counts was 74.9 ± 2.6 dB at the stations situated 60 m from the road, 49.3 ± 2.5 dB at the stations 310 m from the road and 41.2 ± 2.9 dB at the stations 560 m from the road. The abundance and species richness of wintering birds did not depend on distance from the busy road or traffic noise in December, but in next months (January and February) the number of species and bird abundance were lower near the road. There were also differences in the abundance of a particular ecological bird assemblages distinguished according to food preference or social behaviour in relation to distance from the road. The proportion of granivorous birds decreased from December to February and with increasing noise level. The proportion of birds belonging to flocking species was related primarily to survey month and increased from December to February. This case study indicates that, in contrast to the results obtained during the breeding season and the autumn migration in the same study plot, road and traffic noise has no effect on the number of birds in the vicinity of a road during December. However in the next months, in January and February bird abundance and number of species was lower near the road, similar as during breeding and autumn migration periods.

Studies investigating nest function in birds show that individual preferences and environmental temperature can affect the type and amount of materials used in their construction and, thus, how well insulated they are. Levels of insulation of bird nests may be important because this could impact on heat loss by adults and eggs during incubation, and by nestlings during rearing, which may in turn affect individual fitness. Here we used infrared (IR) thermography to measure the surface temperature of nests of Great Tits Parus major and Blue Tits Cyanistes caeruleus in situ during incubation to test the hypothesis that nest insulation predicts reproductive success. Previous studies of thermodynamics during incubation have focussed on factors, e.g. egg temperature, which do not directly measure the thermal conditions in the nest itself. Rarely applied to studies of avian incubation, IR thermography has yet to be used to quantify the thermal properties of nests with the incubating bird in situ. The rate of temperature change (°C/cm) of the nest material, as determined for the first 1.5 cm away from the edge of the bird, was significantly associated with fledging success in Blue Tits, although not Great Tits. This provides the first evidence that the insulatory properties of nests during incubation can correlate with offspring fitness, and so has important implications for the study of nest function in an ecological context. IR thermography provides a methodology that allows future research to investigate the factors that determine nest insulation.

The European Roller Coracias garrulus is a secondary hole-nesting bird that has largely been considered genetically monogamous, although molecular techniques to confirm this assumption had never been used. Here we test this hypothesis by using 5 years of data from a nest-box population in the south of Spain and 6 microsatellite markers recently tested in the species. Overall, 49 broods containing 176 nestlings were included. The average annual percentage of nests with either extra-pair paternity or extra-pair maternity was 4.6 and 6.4, respectively. No evidence of cooperative breeding was found in the provisioning videos analysed. Our work confirms for the first time that European Rollers are not exclusively genetically monogamous, opening new avenues in the study of the breeding biology of this near-threatened species.