Showing papers in "Bird Study in 2015"
TL;DR: In this article, the authors quantify latitudinal and elevational shifts of breeding bird populations in Great Britain and test for differential shifts in range margins during a period of warming (1994-2009).
Abstract: Capsule Abundance monitoring data suggest that the short-term response of breeding birds to recent warming in Great Britain has been range expansion, caused by poleward shifts of leading range margins and no significant shifts of trailing range margins.Aims To quantify latitudinal and elevational shifts of breeding bird populations in Great Britain and test for differential shifts in range margins during a period of warming (1994–2009).Methods We modelled the population density of 80 species as a smooth function of latitude, longitude, elevation and year. Reference points on the distribution curve were used to describe latitudinal and elevational shifts.Results Across species, poleward shifts in the leading range margin were greater than in the range-centre. The trailing range margin was largely static, providing evidence for significant range expansion. The magnitude of latitudinal range shift lagged behind the equivalent shift in temperature, suggesting that species may be accumulating a climatic debt. ...
50 citations
TL;DR: Outer nest wall materials were significantly thicker, stronger and more rigid than materials in the inner structural wall or the cup lining, and materials on the outside of the nest may have a key structural role during construction.
Abstract: Capsule Common blackbirds select different materials, with varying biomechanical properties, to construct different parts of their nest.Aims This study tested the hypothesis that outer components of a nest have a more structural role and so are stronger than materials used to line the cup.Methods Blackbird nests were measured prior to being dismantled to isolate structural components which were tested for mechanical strength and rigidity.Results Outer nest wall materials were significantly thicker, stronger and more rigid than materials in the inner structural wall or the cup lining. In the vertical plane materials used in the structural wall did not differ. By contrast, lining materials from the bottom of the nest cup were significantly thicker, stronger and more rigid than materials from the top of the cup.Conclusion Blackbirds use different materials in nest construction roles suited to their properties and so may be able to recognize the structural properties of these materials. Materials on the outsi...
49 citations
TL;DR: The White Stork can modify its arrival in response to current weather conditions on the breeding grounds but it cannot respond to extreme weather events, and breeding success may decrease in the future.
Abstract: Capsule Although the White Stork avoids adverse weather conditions by modifying its arrival and breeding, it cannot avoid extreme weather events during the breeding season.Aims To show how extreme weather conditions can influence breeding attempts of a large, long-lived species, the White Stork.Methods We analysed data on arrivals of White Storks in Western Poland from 2005 to 2013 and detailed breeding biology parameters from 2009 to 2013 in relation to weather conditions. We analysed breeding success and breeding failure rate from 1974 to 2013.Results In years with a cold March White Storks arrived later than when March was warmer. Frost during incubation negatively influenced the hatching success. Extreme weather events caused high late mortality even for nestlings older than 30 days. Data from 27 breeding seasons showed a significant increase in mean breeding success but also a significant increase in the proportion of pairs which lost broods in the nestling stage.Conclusion The White Stork can modify...
43 citations
TL;DR: Apparent survival after successful breeding is significantly higher than after unsuccessful breeding, because unsuccessful breeders probably move to new breeding sites the following year, probably indicating that site fidelity depends on prior nesting success.
Abstract: Capsule Apparent survival rates of Whinchats breeding in abandoned fields differ in relation to prior breeding success, probably indicating that site fidelity depends on prior nesting success.Aims To examine apparent survival, and hence site fidelity, and its association with previous breeding success in Whinchats breeding in abandoned fields.Methods We ringed and measured apparent survival and age ratios of Whinchats in abandoned fields over nine years. We modelled the impact of age, nest stage, and time of season on daily nest survival rates.Results There were 3.77 fledglings per pair (n = 251). Annual variability and a nest age effect were the most important components of nest survival variation. Adult apparent survival after successful breeding was 0.32 ± 0.08 and after unsuccessful breeding this was 0.11 ± 0.08. Among 229 males with known age, 39% were second calendar year, and 61% were older than the second calendar year. From 744 ringed nestlings only 7 birds returned the following years.Conclusion...
27 citations
TL;DR: In this paper, the authors compared breeding time, productivity and pairing pattern of Crested Goshawk populations between urban and rural areas, and concluded that the urban population benefits from high food productivity and higher nesting success.
Abstract: Capsule A Crested Goshawk population recently colonizing an urban area of Taiwan is characterized by earlier egg-laying dates, a higher ratio of mixed-age pairs and higher nesting success.Aims To compare breeding time, productivity and pairing pattern of Crested Goshawk populations between urban and rural areas.Methods A total of 117 nests, comprising 49 rural and 68 urban ones, were monitored in Taichung, central Taiwan over six years. Age of parents, egg-laying date, clutch size and number of fledglings were recorded from each nest.Results The urban Crested Goshawk bred 34 days earlier on average than the rural population with a significantly higher nesting success. Mixed-age pairs occurred in a higher frequency in urban (30.9%) than in rural (14.3%) areas. Predation (55.6%) and inclement weather (27.8%) were the two main factors causing nesting failures in rural areas, whereas neither occurred in the urban area.Conclusion We conclude that the urban Crested Goshawk population benefits from high food sup...
26 citations
TL;DR: Nest-site competition between cavity-nesting birds and bumblebees and wasps appears to be a ‘nest-box phenomenon’, which may occasionally interfere with nest-box studies, but appears negligible in natural nest-sites.
Abstract: Capsule There is no evidence of widespread significant nest-site competition in Britain or the Western Palearctic between cavity-nesting birds and bumblebees or social wasps.Aims To investigate competition between cavity-nesting birds and bumblebees and wasps, particularly the range-expanding Tree Bumblebee, Saxon Wasp and European Hornet in Britain, and review evidence throughout the Western Palearctic.Methods We compared field data from English and Polish studies of tits and woodpeckers breeding in nest-boxes and/or tree holes to assess nest-site competition with bumblebees and wasps. We reviewed the literature quantifying nest-site competition between birds and these insects in the Western Palearctic.Results Bumblebees and wasps are capable of usurping small passerines from nests. In England, these insects commandeered a mean annual 4.1% of tit nests initiated in nest-boxes; occurrence of hornets showed a long-term increase, but not other wasps or bumblebees. Across the Western Palearctic, insect occup...
22 citations
TL;DR: Food and nesting site availability are key drivers in limiting more specialist species in utilizing city centres and future studies should assess the effect of how green areas can counteract such negative effects of increasing urbanization in the context of such specialist trait limitations.
Abstract: Capsule Urbanization effects in an Eastern European city depend on feeding and breeding traits of bird communities with stronger negative effects on more specialized traits.Aims To assess how urbanization affects feeding and breeding traits of bird communities in Cluj (Romania).Methods Based on a stratified random sampling we selected 61 study squares of 200 × 200 m for bird surveys representing the following habitats: suburban, residential and apartment complex (representing an increasing urbanization gradient). We carried out bird censuses in both breeding and wintering seasons. The observed bird species were classified according to their feeding guilds and nesting sites.Results Insectivorous and open-cup nesting species were most abundant in suburban areas. Omnivorous species richness was not related to urbanization gradient. Species showed similar patterns of distribution during breeding and winter with respect to feeding habits. However, in case of nesting preferences, species richness of cavity nest...
21 citations
TL;DR: The negative relationship between nest size and time of nest failure suggests that nest size parameters are adjusted to avoid predation, and the speed, nest height and experience hypotheses.
Abstract: Capsule We examined intraspecific variation in the nest size of open cup nesting Blackbirds Turdus merula and found that of seven variables considered, nest size variation was determined by the length of the nest construction period, nest height and the experience of the building female.Aims We tested seven hypotheses to investigate the influence of the following factors on nest size: (A) speed of construction: smaller nests are constructed faster; (B) nest height: nests placed higher up are smaller; (C) experience: inexperienced females construct smaller nests; (D) predation pressure: predation is less on smaller nests; (E) clutch size: larger nests contain larger clutches; (F) nest placement: nests constructed in open areas are larger than those situated in well-concealed sites and (G) incubation: larger and thicker nests are constructed during colder periods.Methods We used data from 54 Blackbird females nesting (73 nests) in two urban parks.Results Our data supported the speed, nest height and experie...
20 citations
TL;DR: In this article, the authors found evidence of an interglacial refugium during the Last Interglacial for birds in Anatolia and suggested the need of a re-examination of the effects of the last glacial on the geographic distribution and genetic structure of species.
Abstract: Capsule This study is the first ever documented evidence of an interglacial refugium during the Last Interglacial for birds in Anatolia and suggests the need of a re-examination of the effects of the Last Interglacial on the geographic distribution and genetic structure of species.Aims We tested whether, in accordance with the ‘refugia within refugia’ model, multiple refugia existed for Kruper's Nuthatch Sitta krueperi during the Last Glacial Maximum or the species survived along the coastal belt of Anatolia through the Late Quaternary glacial–interglacial cycles.Methods An ecological niche model was developed to predict the geographic distribution of Kruper's Nuthatch under reconstructed past (the Last Interglacial and the Last Glacial Maximum), present, and projected future bioclimatic conditions. Also, robust coalescent-based analyses were used to assess demographic events over the history of Kruper's Nuthatch.Results Kruper's Nuthatch survived the Last Glacial Maximum almost along the coastal belt of ...
19 citations
TL;DR: High Marsh Harrier predation rates (attacks from the air) may explain why water depth did not affect the survival rate of natural and artificial nests and why nest concealment was a factor positively influencing the nest success of the Water Rail andificial nests.
Abstract: Capsule Nest survival of Water Rail and Little Crake nesting at small, midfield ponds was determined by vegetation density and proximity to the shore, respectively.Aims To determine which habitat variables affect nest predation for two rallid species inhabiting small ponds.Methods Habitat variables describing nest location (water depth, distance to the shore and distance to open water) and nest concealment (density and height of vegetation) were measured for natural and artificial nests. All nests were monitored to determine their fate and to identify nest predators. We used generalized linear models to assess nest survival rates and to evaluate the influence of particular variables.Results Little Crake nest success was negatively correlated with distance to shore (the land-water edge). The survival of Water Rail nests and artificial nests was positively correlated with vegetation density. During three breeding seasons, predation rates on Little Crake nests varied from 22% to 58%, and on Water Rail nests ...
18 citations
TL;DR: Common Swift nestlings’ growth, but not survival, was affected by meteorological conditions, with moderate rainfall, moderate winds and high temperatures favouring greater mass gain.
Abstract: Capsule Hatching order negatively affected Common Swift Apus apus nestlings’ survival, while brood size and meteorological conditions influenced their growth patterns.Aims To investigate the influence of hatching date, age, sex, brood size and meteorological conditions on survival and growth of Common Swift nestlings from Northern Italy (Southern Europe), a relatively warm and dry part of the distribution range of this species.Methods Nestlings were weighed at regular intervals and molecularly sexed. Growth patterns were described using a double-Richards growth curve, i.e. a growth curve that also accounted for the pre-fledging mass loss. We also identified the Linear Growth Phase (i.e. when nestlings grew at the fastest rate).Results Mortality increased with hatching order and decreased with brood size. Mortality was highest for fourth-hatched nestlings, none of which survived. Nestlings hatched late in the season grew faster, experienced the fastest growth rate at a younger age, but reached a lower maxi...
TL;DR: In this article, the authors tracked the migration of Red-spotted Bluethroats from Europe to the hitherto unknown non-breeding areas and back using light-level geolocators.
Abstract: Capsule Red-spotted Bluethroats Luscinia s. svecica from two European breeding populations spent the boreal winter on the Indian sub-continent.Aim Tracking the migration of Red-spotted Bluethroats from Europe to the hitherto unknown non-breeding areas and back.Methods Light-level geolocators were deployed on male Bluethroats at breeding sites in the Czech Republic (n = 10) and in Norway (n = 30). Recorded light intensity data were used to estimate the locations of non-breeding sites and migration phenology during the annual cycle.Results Bluethroats spent the boreal winter in India (n = 3) and Pakistan (n = 1), on average more than 6000 km from their breeding areas. Autumn migration started in August (n = 1) or early September (n = 2), and lasted for 26–74 days. Spring migration commenced on 8 and 9 April (n = 2) and lasted for about a month. During both autumn and spring migration, birds stopped over two or three times for more than 3 days.Conclusion This study for the first time showed where Red-spotted...
TL;DR: The diet of the Long-eared Owl Asio otus in urban environments during the winter was reviewed using studies which reported the ingested biomass relating to different prey categories and so energy intake could be considered.
Abstract: Capsule Although considered as a specialist predator of Microtus voles, the Long-eared Owl Asio otus may adapt its diet according to the local prey availability We reviewed the diet of this nocturnal raptor in urban environments during the winter, using studies which reported the ingested biomass relating to different prey categories and so energy intake could be considered The species was confirmed to feed mainly on Microtus, but in some area rats dominated the ingested biomass
TL;DR: Differences in trends between sexes suggest a role for an interplay between natural and sexual selection with latitude that deserves further consideration.
Abstract: Capsule An analysis of body mass and wing length for four bird species shows trends broadly in line with predictions from Bergmann's and Allen's rules but with species- and sex-specific trends in terms of body size variation with latitude in BritainAims To analyse body size characteristics for bird species with latitude in Britain and to test Bergmann’s and Allen’s rules (over a range of c 740 km)Methods Body mass and wing length for four bird species (Blackbird Turdus merula, House Sparrow Passer domesticus, Robin Erithacus rubecula, and Song Thrush Turdus philomelos) were analysed using principal components regression analysis to investigate trends with latitude, longitude, or by sex and Julian dayResults Evidence was found for latitudinal gradients in body mass for male Blackbird, female House Sparrow (both increasing in size northwards), and female Robin (decreasing in size northwards) and in wing length for female Robin and male Song Thrush (decreasing and increasing northwards, respectively)Con
TL;DR: In this paper, the authors carried out radio-telemetry on Black Grouse over three years to investigate individual habitat use, and used compositional analyses to investigate habitat selection in different seasons.
Abstract: Capsule Long-term conservation of Black Grouse in Scotland may rely upon the retention of sufficiently large and well-connected patches of moorland and a diversity of adjacent forest types.Aims To study Black Grouse habitat use within a moorland-forest mosaic and make recommendations for their conservation in more heavily forested future landscapes.Methods We carried out radio-telemetry on Black Grouse over three years to investigate individual habitat use. We used compositional analyses to investigate habitat selection in different seasons. We examined whether this matched previous population-level patterns and whether it differed between males and females. We used logistic regression to examine whether movements into large-scale commercial forests were restricted to the periphery relative to random locations.Results Males used seasonal ranges of >200 ha and females >70 ha. Birds selected strongly for moorland throughout the year, matching other population-level studies. Underlying this, however, males a...
TL;DR: In this article, game birds as surrogate carcasses for raptors could significantly bias calibration searches for wind turbine collision fatalities, leading to significant bias bias bias in the search for collision fatalities.
Abstract: Capsule Using game birds as surrogate carcasses for raptors could significantly bias calibration searches for wind turbine collision fatalities.
TL;DR: Capsule Data from geolocators deployed on adult Common Guillemots from a colony in southeast Scotland indicated that they normally winter in the North Sea up to 1000 km southeast of the colony, but one bird unexpectedly moved 3000’�km northeast to moult in the Barents Sea.
Abstract: Capsule Data from geolocators deployed on adult Common Guillemots from a colony in southeast Scotland indicated that they normally winter in the North Sea up to 1000 km southeast of the colony. However, one bird unexpectedly moved 3000 km northeast to moult in the Barents Sea.
TL;DR: Both Levaillant's and Great Spotted Woodpecker showed high requirements for large-diameter trees and snags, which provide substrates for both nesting and foraging, which calls for caution when planning for woodpecker conservation.
Abstract: Capsule Nests of Levaillant's Woodpecker Picus vaillantii and Great Spotted Woodpecker Dendrocopos major were associated with higher densities of snags and downed wood than foraging locations.Aims To quantify the nesting requirements of two sympatric woodpecker species in Tunisian oak forests.Methods We compared habitat structure around nests and foraging locations for both woodpecker species using logistic regression. We examined evidence for preferences in nesting substrates using resource selection indices. Then, we used discriminant function analysis to identify variables separating nesting, foraging, and unused habitat of each species.Results The probability of presence of nests of both species was significantly related to densities of downed wood and snags. Nests of Levaillant's Woodpecker were located in areas with slightly higher snag densities. Habitat structure differed between nesting and foraging locations of Great Spotted, but not Levaillant's WoodpeckerConclusion Both Levaillant's and Great ...
TL;DR: Advances in timing of breeding have not led to increased Willow Warbler productivity in the UK, because the population-level impact of advances depends on seasonal patterns in both productivity and the distribution of nesting dates within a population.
Abstract: Capsule Breeding Willow Warblers, Phylloscopus trochilus, in the UK have advanced in timing of breeding but with little impact on overall productivity.Aims To quantify the impact of shifts in timing of breeding on changes in Willow Warbler productivity across the UK.Methods Using records of ∼7000 nests from the British Trust for Ornithology Nest Record Scheme, we quantify shifts in timing of breeding and seasonal variation in productivity and timing of breeding, and explore their relative contribution to changes in overall productivity. As population trajectories vary across Britain (south-east declining, north-west stable), analyses were conducted regionally.Results In both regions, nesting dates have advanced and early-season productivity is highest. However, while the proportion of early-season nests has increased, the seasonal decline in productivity in the north-west has lessened, and overall (season-long) productivity is stable. In the south-east, however, the seasonal decline in productivity has st...
TL;DR: It is shown that the height of 20 researchers, selected to represent a diversity of heights, did not affect estimates of flight-initiation distance of Black Swans Cygnus atratus, suggesting that the Height of humans used to test hypotheses ofFlight-Initiation distances is not a confounding variable.
Abstract: Capsule Responses of animals to anthropogenic disturbances are often quantified using flight-initiation distance, the distance at which an animal flees a stimulus such as a person. We showed that the height of 20 researchers, selected to represent a diversity of heights, did not affect estimates of flight-initiation distance of Black Swans Cygnus atratus, suggesting that the height of humans used to test hypotheses of flight-initiation distances is not a confounding variable.
TL;DR: Great Bustards can adapt to an intensive agricultural setting, but require unrestricted access to adjacent grasslands, and would be best served with small-scale habitat mosaics.
Abstract: Capsule Reintroduced Great Bustards achieve dietary and habitat diversity despite living in an intensive agricultural setting. Aims To investigate dietary composition and habitat use of reintroduced Great Bustards Otis tarda released in southwest England and the impact of supplemental feed on autumn dietary selection. Methods Faecal samples were collected from a mixed group of free-ranging bustards without (July 2012, May, September, and November 2013) and with (October and December 2012) access to supplemental feeds. Concurrently, diurnal land use observations were recorded for all months but September and December. Composite monthly faecal samples were micro-histologically analysed to assess dietary composition. Year-round landscape-level habitat use was determined using re-sightings and satellite telemetry data for birds surviving more than 182 days post-release. Generalized linear models were used to test for differences in habitat selection across the year, by sex and within and outside release areas for each habitat type, and habitat diversity was quantified using the Shannon–Weaver Index. Results Dietary composition varied depending on plant availability and phenological stage, and invertebrates were rarely selected. Agricultural crops – primarily oil-seed rape, mustard, barley grass, lucerne, and barley seed – comprised the bulk of the diet, but grassland and weedy forbs were always important secondary foods (>25%), except when provided extruded pellets. Monthly changes in habitat use suggest sex-based habitat segregation, with females living in higher habitat diversity settings. Grasslands were used across the year. When supplemental food was provided, it came to dominate dietary intake. Conclusion Great Bustards can adapt to an intensive agricultural setting, but require unrestricted access to adjacent grasslands. They would be best served with small-scale habitat mosaics. If supplemental foods are to be provided to juvenile birds, quantities must be limited and the birds weaned off before dispersal to maximize reintroduction success.
TL;DR: The British breeding Woodcock population in 2013 was estimated at 55,241 males (95% CL: 41,806,69,004), suggesting a large-scale decline that is supported by 2 additional sources of data as discussed by the authors.
Abstract: Capsule The breeding Woodcock population in Britain in 2013 was estimated at 55 241 males (95% CL: 41 806–69 004), suggesting a large-scale decline that is supported by 2 additional sources of data.Aims To provide an updated estimate of the size of Britain's breeding Woodcock population, measure recent trends and identify spatial patterns of change.Methods Displaying male Woodcock were surveyed at a stratified sample of 834 randomly selected sites. Population estimates were compared with a baseline survey conducted in 2003 and the trend with data from annual Woodcock counts (2003–13) and Bird Atlas 2007–11.Results Woodcock were estimated to be present at 22% of 1 × 1 km squares containing ≥10 ha of woodland, compared to 35% in 2003. The British population estimate fell by 29% between 2003 and 2013. The Atlas suggests that presence at the 10 × 10 km scale has declined by 56% between 1970 and 2010. Both data sources suggest regional variation in the rate of decline, with losses greatest in the West and Sout...
TL;DR: In this paper, a comparison of various methods of counting a Corncrake population revealed that the accuracy of counting depends on population density, which could have important ramifications for a monitoring scheme.
Abstract: Capsule A comparison of various methods of counting a Corncrake population revealed that the accuracy of the methods depends on population density, which could have important ramifications for a monitoring scheme.Aims We examined the accuracy of three counting methods – territory mapping, point-based censusing, and point counting – in evaluating the population size and spatial distribution of the Corncrake, a species that uses long-range acoustic communication.Methods We performed single-visit counts within ten study plots (1 km2). Each study plot was censused in a single night using all counting methods. With territory mapping, we approached each calling male and recorded his position with a Global Positioning System (GPS) receiver. In point-based censusing, we estimated the distance and direction to calling males from five points in each study plot, while with the point-counting method, we only recorded the number of males within each of four distance categories, which estimated the distance from the sa...
TL;DR: Bathymetry likely influences the dive behaviour of this benthic-feeding species because most dives were U-shaped and dive depths were shallow, which is typical for the relatively shallow water where the birds were observed foraging.
Abstract: Capsule Dive behaviour in Black Guillemots Cepphus grylle was close to that predicted for a benthic forager by allometry based on body mass.Aims To report the diving behaviour of Black Guillemots in Northern Ireland.Methods A time-depth-recorders and GPS logger were deployed on four chick-rearing breeding Black Guillemots.Results Dive shape implied most dives were benthic with a small number at the start of each bout associated with searching. Diving only occurred during daylight hours, but dive depth was unrelated to light availability outside of the twilight periods. Dive durations (max = 90 s; mean = 54 s) were shorter and dive depths (max = 15 m; mean = 9 m) were shallower than recorded for guillemots elsewhere. The birds dived a maximum of 1.8 km from the colony.Conclusions Black Guillemots' dive duration was similar to the value predicted from allometry, and is therefore likely representative of this species. Bathymetry likely influences the dive behaviour of this benthic-feeding species because mos...
TL;DR: The analysis of 635 papers about the diet of the European Barn Owl Tyto alba showed that 83'751 birds were captured out of 3.44 million prey items (2.4%).
Abstract: Capsule The analysis of 635 papers about the diet of the European Barn Owl Tyto alba showed that 83 751 birds were captured out of 3.44 million prey items (2.4%). Birds were more frequently captured on islands than mainland, in southern than northern Europe and in eastern than western Europe. Between 1860 and 2012, the consumption of birds decreased in northern and eastern Europe. Among avian prey, the House Sparrow Passer domesticus, the most frequently captured bird (65.7%), decreased in frequency during the last 150 years in eastern Europe.
TL;DR: In this paper, a set of free and available online environmental variables were used to predict the breeding localities of the white stork in Southeast Europe, and the presence-absence model was found to be precise in predicting the presence of nests.
Abstract: Capsule Spatial environmental modelling well predicted nesting distribution of the White stork in Southeast Europe and can be used in conservation planning with respect to climate change.Aims To create spatial models for predicting White Stork presence and densities in the Southeast Europe to identify areas of suitable habitat for White Storks.Methods We quantified the habitat used by nesting White storks in Southeast Europe. Using spatial modelling, we defined a set of free and available online environmental variables that predict the breeding localities of the species. We employed pseudo-absences and the kriging of the residuals in order to create predictive models of nest presence and density.Results The presence–absence model was found to be precise in predicting the presence of nests. Both density and presence of breeding pairs were best explained negatively by elevation, slope, minimum temperature during May, and distance to the nearest human settlement and positively by topographic wetness index, t...
TL;DR: Breeding success was markedly affected by a weather event happening one month before hatching and lasting only a few days, an increased frequency of extreme weather events as predicted by some climate change scenarios may dramatically affect insectivorous avian populations in the future.
Abstract: Capsule Very low and anomalous temperatures in early spring of 2010 were followed by the only massive reproductive failure event recorded in 24 years in a population of Pied Flycatchers Ficedula hypoleuca breeding at 1200 m altitude in central Spain.Aim To estimate the effects of an extreme climatic event on reproductive success in a montane population of a long-distance migratory bird.Methods We compared nestling growth and mortality in nests of different brood sizes in the context of a brood manipulation experiment.Results Total failure affected 36% of the broods and only 2.5 nestlings on average were raised to fledging age. Most mortality affected broods in the second week of nestling life. Fledglings attained very low values for mass and wing length compared with long-term averages. Subsequent local recruitment was the lowest for any cohort in 24 years. The typical date-dependent decrease in breeding success in the population was inverted.Conclusion Breeding success was markedly affected by a weather ...
TL;DR: The catch of non-fish prey appears to be accidental, and is more likely a result of target misinterpretation than a Kingfisher regularly switching to prey other than fish.
Abstract: Capsule Non-fish prey constitutes an important component of the diet of many fish-eating birds.Aims In the present study, the role of non-fish prey in the diet of the Common Kingfisher Alcedo atthis was evaluated.Methods The species and size spectrum of prey in the diet was studied at 15 nest sites on 6 trout streams, 1 river and 1 reservoir in the Czech Republic, using the analysis of the nest sediment.Results 16 933 individual prey items were identified (99.93% fish and 0.07% non-fish prey). European Perch Perca fluviatilis, Roach Rutilus rutilus and Bleak Alburnus alburnus dominated the diets on the reservoir; Gudgeon Gobio gobio, European Chub Squalius cephalus and Roach those on the river; and Gudgeon, European Chub, Bullhead Cottus gobio, Roach, Bleak and Brown Trout Salmo trutta m. fario those in the trout streams. The sizes of their fish prey ranged from 16 to 134 mm in total length (LT) with an average size of 66 mm. The remains of non-fish prey were detected in only 5 of 30 nest sediments. The n...
TL;DR: The findings suggest that other birds and their eggs do not represent an important food for magpies in Mediterranean agricultural environments under the conditions found during this study.
Abstract: Capsule Feeding habits of the Black-billed Magpie are of interest for researchers, conservationists and hunters since magpies are considered as predators of eggs and chicks of both songbirds and gamebirds.Aims To characterize the feeding habits of magpies during their breeding season in agricultural environments of central Spain, and to assess the occurrence and incidence of birds and eggs in the magpie's diet.Methods Diet was determined by the analysis of gizzard contents from 118 culled magpies. The diet was described as the frequency of occurrence (FO) and the percentage of volume (VOL) of a certain food item and for each gizzard.Results Magpies presented a generalist diet, which included a wide range of foods. Arthropods and cereal seeds were the most frequently consumed food groups (FO > 60%). Eggs and birds were consumed only occasionally (FO < 6% and 17%, respectively; percentage of volume, VOL < 4%).Conclusion Our findings suggest that other birds and their eggs do not represent an important food ...
TL;DR: The third survey of breeding waders in Northern Ireland showed large declines in the abundance of Eurasian Curlew, Northern Lapwing and Common Snipe since 1987 as mentioned in this paper, which represents significant declines in abundance of 82%, 89% and 78% respectively since 1987.
Abstract: Capsule The third survey of breeding waders in Northern Ireland showed large declines in the abundance of Eurasian Curlew, Northern Lapwing and Common Snipe since 1987.Aims To estimate the size of the breeding populations of selected breeding wader species in Northern Ireland in 2013 and population changes since previous surveys in 1987 and 1999.Methods Complete surveys of all potentially suitable breeding habitats were undertaken in randomly selected 2 km squares in each of 146 land-dominated 10 km squares across Northern Ireland. Square selection and a two-visit field method replicated previous surveys conducted in 1987 and 1999.Results Northern Ireland breeding populations of Eurasian Curlew, Northern Lapwing and Common Snipe were estimated to be 526 (±95% CI: 252–783), 860 (277–1545) and 1123 pairs (527–1782), respectively. These estimates represent significant declines in abundance of 82%, 89% and 78% respectively since 1987.Conclusion Breeding populations of Eurasian Curlew, Northern Lapwing and Com...