ABSTRACT Capsule: Linear censusing and occupancy models based on fixed sampling points are alternative widely used techniques to determine bird densities in riparian ecosystems, although it cannot be always properly executed. Aims: The aim is to assess the survey efficiency for river birds using occupancy models in contexts of impaired visibility owing to dense vegetation along the banks. Methods:

ABSTRACT Capsule: Wintering male Bull-headed Shrikes Lanius buchepalus preferred vegetable fields with perch sites to search for and detect terrestrial prey, and males occupying territories with large areas of vegetable fields acquired more prey and cached more food. Aims: To better understand effects of habitat use on food acquisition and food caching of the Bull-headed Shrike, we investigated relationships

ABSTRACT Capsule: Non-breeding waterbirds are more likely to respond to drone approach when in larger flocks, and responses are more likely in arable and coastal habitats than at inland lochs. Aims: To investigate the extent to which drones are a potential source of disturbance to non-breeding waterbirds. Methods: Using a commercially available quadcopter drone, we approached waterbird flocks of varying

ABSTRACT Capsule: The Crested Lark Galerida cristata as an example of a species which selects habitats which have undergone agricultural intensification. Aims: To describe habitat preferences of the Crested Lark in western Poland. Methods: We surveyed 30 randomly chosen study plots (1 km2) in western Poland to detect breeding pairs of Crested Larks. Sentinel and direct observations in the field were

ABSTRACT Capsule: Despite its population increase, the White-tailed Eagle Haliaeetus albicilla has not become food-limited, and does not pose a serious threat to birds of conservation concern in the region east of the Baltic Sea. Aims: We aimed to test variations in the main prey groups and dietary niche breadth of White-tailed Eagles through the years and along an environmental gradient as well as

ABSTRACT Capsule: Fitting geolocators to Common Sandpipers Actitis hypoleucos did not affect their return rates, return dates, body condition or reproductive success, but did cause leg injuries in some individuals. Aims: To investigate the effect of fitting geolocators to Common Sandpipers on their return rates and timing, the condition in which they return and their subsequent breeding success. Methods:

ABSTRACT Capsule: Diet analysis revealed high lead exposure for Greater Spotted Eagles Clanga clanga wintering in southeast Spain. Aims: To describe the diet composition of the endangered Greater Spotted Eagle in a wintering area located in southeast Spain, and determine lead ammunition exposure through analysis of regurgitated pellets and prey remains. Methods: Between 2008 and 2018, a total of 26

ABSTRACT Capsule: The mating system of the Brown Accentor Prunella fulvescens in the high altitudes of the Tibeta plateau is mainly monogamous but polyandry was recording in 9.7% of breeding groups. Aims: To describe the poorly known breeding biology of Brown Accentors in the high-altitude environment of the northeastern Tibet plateau. Methods: Individually colour-ringed birds were observed during

ABSTRACT Capsule: The use of mist nets placed at more than 9 m high and small GPS tags fitted with a pelvic harness, and equipped to download remotely, allows the capture and tracking of breeding White-backed Woodpeckers Dendrocopos leucotos. Aims: To describe and test a method for capturing, ringing and GPS-marking medium-sized woodpeckers. Methods: Birds were captured using an overlapping mist net

ABSTRACT A ‘call count’ survey of Water Rails Rallus aquaticus, using broadcast vocalizations to elicit a response, was carried out on Alderney over two consecutive winters. The species was found to be widespread on the island, with 34 birds found in both winters. Most, 62% in each winter, occurred in habitats associated with water, but 38% unexpectedly occupied drier habitat. The survey presents new

ABSTRACT Eighty-two nest and roosting cavities of Syrian Woodpeckers Dendrocopos syriacus were documented over a period of 25 years (1994–2018). Fourteen different tree species were used, the majority being non-native in Hungary. Cavities were found in both main trunks and in larger limbs. The median cavity height was 3.0 m and ranged from 1 to 7 m. The cavity entrance orientation was non-random with

ABSTRACT ‘Peeks’, or keeping an eye open, in wintering Common Pochard Aythya ferina, while in a sleeping posture, were relatively brief, typically (66% of observations) lasting less than one second. However, in 37% of individuals some peeks lasted 10 s or more. Contrary to our prediction of lower anti-predatory vigilance rates in larger groups, there was a positive relationship between peek duration

ABSTRACT Log transformations of density values in the form log(count)/log(area), as used in a recent paper in this journal, do not preserve the rank order of the untransformed density values and are dependent on the units used for area. The appropriate log transformation of density is log(count/area).

ABSTRACT In this reply, we confirm that the results of the original paper are robust and that our conclusions were correct: densities of Ruddy Turnstones Arenaria interpres were lower on sites located further from undisturbed refuges. There are two points of learning here: (i) taking the findings of a paper based purely on what is published is normal but there is an unpublished iterative process for

Capsule: The mating system of the Brown Accentor Prunella fulvescens in the high altitudes of the Tibeta plateau is mainly monogamous but polyandry was recording in 9.7% of breeding groups. Aims: To describe the poorly known breeding biology of Brown Accentors in the high-altitude environment of the northeastern Tibet plateau. Methods: Individually colour-ringed birds were observed during two breeding

Capsule: Despite its population increase, the White-tailed Eagle Haliaeetus albicilla has not become food-limited, and does not pose a serious threat to birds of conservation concern in the region east of the Baltic Sea. Aims: We aimed to test variations in the main prey groups and dietary niche breadth of White-tailed Eagles through the years and along an environmental gradient as well as to evaluate

Capsule: There was significant variation on the incidence of road traffic mortality across bird species, due to seasonal and weather effects but also due to differences between years. Aims: To assess patterns of mortality due to traffic collision for six common bird species over a period of nine years in relation to seasonality and weather. Methods: Road mortality surveys were performed on four road

Capsule: Annual reproductive parameters of Little Egrets Egretta garzetta in an Atlantic coastal colony showed strong variation in a 20-year study, mainly due to extreme events. Aims: To describe the breeding biology of Little Egrets in the Bay of Biscay and compare it with that of the Mediterranean basin. Also, to explore relationships between breeding parameters and colony size with some climatic

Capsule: A data-thinning approach was used to assess the effects of reducing the frequency of nest-checks on estimates of breeding success of Common Guillemots Uria aalge. Inter-year and inter-colony differences in fledging age and their implications for setting a minimum age after which a chick could be assumed to have fledged were evaluated. Aims: To assess the consequences of reducing sampling frequency

Capsule: An experiment in the field supports the hypothesis that Grey Partridges Perdix perdix purposely expose their first laid eggs in order to test the predation risk at their nest site. Aims: To test the hypothesis that female Grey Partridges leave first laid eggs uncovered to assess the predation risk at their chosen nesting site. Methods: Four area-independent experiments with artificial nests

Capsule: There has been no trend in nest survival of Lesser Spotted Woodpecker Dryobates minor in the 70 years since the 1940s whereas the numbers of young per nesting attempt has declined. Late nests in any year are now significantly less productive than early ones. Aims: To test whether there has been a long-term decline in the nest survival and productivity of the Lesser Spotted Woodpecker in Britain

ABSTRACT Capsule: Two distinct song types were identified for male European Nightjars Caprimulgus europaeus with their relative frequency of use changing through the breeding season, indicating a possible link to paired status. Aims: To test whether two song types could be defined in audio recordings and whether use differed in relation to the paired status of males. Methods: Unattended acoustic recording

Capsule: We document previously undescribed nocturnal flight behaviour by Bearded Vultures Gypaetus barbatus using a combination of accelerometer and global positioning system (GPS) information. Aims: To study the nocturnal flight activity of the Bearded Vulture and determine whether nocturnal flights could be linked to foraging behaviour. Methods: We used both accelerometer and GPS location data of

ABSTRACT Capsule: Duration and peak frequency of Wren Troglodytes troglodytes songs differ between Welsh islands (Skokholm, Flat Holm, and Sully Island) and a mainland site, suggesting random or cultural divergence. Aims: The study tests for differences in bioacoustic traits in Wren song between four breeding sites. Methods: Songs from breeding male Wrens were recorded from three Welsh islands and

ABSTRACT Capsule: Within breeding season changes in nest orientation of the Rufous Hornero Furnarius rufus may reflect responses to the local climate. Aims: To explore the effect of climate on the orientation of closed-cup nests of the Rufous Hornero at a subtropical urban site throughout its breeding period. Methods: The breeding season was divided into two periods: a cold period with low rainfall

ABSTRACT Capsule: The distribution range of the European Roller Coracias garrulus has undergone large changes over geological times, but although the species is warm-adapted, the human induced climate change is predicted to affect negatively the range of the currently large populations. Aim: Information on species-specific vulnerability to climate change is crucial not only for designing interventions

Capsule: We document previously undescribed nocturnal flight behaviour by Bearded Vultures Gypaetus barbatus using a combination of accelerometer and global positioning system (GPS) information. Aims: To study the nocturnal flight activity of the Bearded Vulture and determine whether nocturnal flights could be linked to foraging behaviour. Methods: We used both accelerometer and GPS location data of

Pellets of indigestible material regurgitated by Herring Gulls Larus argentatus breeding on Lady Isle, Firth of Clyde, Scotland, were collected in 2018 and 2019 and examined for earthworm chaetae. Nearly two-thirds (65.6%) of the 314 pellets came from gulls that had consumed one or more earthworms. Significantly fewer pellets (57.6%) contained chaetae in 2018, a relatively dry May to July, than in

Capsule Patterns in the frequency and co-occurrence of anthropogenic pressures associated with suitable breeding habitat for Hen Harriers Circus cyaneus demonstrates the need for specific, focussed management and policy options aimed at mitigating impacts on this threatened population. Aims To describe anthropogenic pressures and threats in the upland breeding range of Hen Harriers and to explore their

Capsule: Black-tailed Godwits Limosa limosa show sexual size dimorphism and size differences between the subspecies. The shape varies slightly between the subspecies, but not between the sexes. Aims: To investigate whether and how the three subspecies of Black-tailed Godwits, and the sexes of these subspecies, differ in size and shape. Methods: We collected body dimensions (lengths of the bill, total

Capsule: Scottish-breeding Greenshanks Tringa nebularia migrate largely to Ireland. Aims: To describe the migration timings and determine the non-breeding areas (staging and wintering areas) of Scottish-breeding Greenshanks. Methods: Breeding adult Greenshanks were marked with geolocators and/or unique permutations of colour-rings in Sutherland, northern Scotland. Sightings of the colour-ringed birds

Capsule: The movements and spatial ecology of non-breeding Eurasian Griffon Vultures Gyps fulvus in northern Italy, Croatia and Austria do not seem to be affected by feeding station use. Aims: The purpose of this study was to assess how the creation of a feeding station at the Riserva Naturale Regionale del Lago di Cornino (Forgaria nel Friuli, northeast Italy) during the 1980s might have affected

We report nine cases of brood parasitism in the endangered Jankowski’s Bunting Emberiza jankowskii by cuckoos in Inner Mongolia Province, China in 2018 and 2019. DNA-based and morphological evidence suggested that five chicks and four eggs of brood parasites were all Common Cuckoo Cuculus canorus, for which the Jankowski’s Bunting is a regular host.

Capsule: The introduced Red-billed Leiothrix Leiothrix lutea can greatly expand its range in Italy, with many regions being at high risk of invasion due to their high habitat suitability. Aims: To assess the environmental variables affecting the distribution of the Red-billed Leiothrix during the invasion process, and to predict the potential distribution of the species in Italy. Methods: We retrieved

Capsule: Voles predated by Long-eared Owls Asio otus were more likely to be female and smaller than the voles in the available population. Aims: Our study aimed to estimate the size and sex of prey in the diet of Long-eared Owls and compare them with the size and sex of prey in the field. Methods: The study was carried out in 2016 and 2017 at Moscow Region, Russia. Prey remains were extracted from

Capsule: We used data from different sources, developed and applied several estimation methods, and confronted the resulting estimates with species experts to achieve breeding size population estimates for all bird species currently breeding in Switzerland. Aims: Population size estimates of birds have a wide range of practical conservation uses. As part of the Swiss Breeding Bird Atlas 2013–2016,

Capsule: We developed a protocol for efficient monitoring of potential Common Swift Apus apus nest sites which considers variation in nest visit frequency across the breeding season and in relation to time of day and weather. Aims: To investigate patterns of nest visit frequency in Common Swifts in order to improve the efficiency and reliability of the monitoring of nest sites threatened by building

Capsule Black Grouse Lyrurus tetrix in southern Scotland are in severe decline, with remaining birds associated with large contiguous patches of moorland. Aims To inform Black Grouse conservation programmes in southern Scotland we quantified recent trends in numbers, assessed habitat composition within lek ranges and evaluated the size of suitable habitat patches. Methods We explored trends in numbers

Capsule: Differences in parental investment between sexes and stage of the breeding period were found in Bonelli’s Eagles Aquila fasciata. Aims: To describe the sexual differences in parental behaviour of Bonelli’s Eagles and to assess the sex-specific pattern of variation in parental investment in relation to the breeding period. Methods: Between 2006 and 2016, we monitored the parental behaviour

Capsule: Parent body colouration and nesting habitat may influence nest predation risk and, therefore, influence parental decisions on offspring care. Aims: To investigate the adaptiveness of bird colouration under two different habitat and light conditions. Methods: We used painted polyurethane dummies to simulate parental presence near nests, where some dummies were red, and others were cryptic brown

Capsule A combination of several biometric measures enables the reliable sexing of the European Bee-eater Merops apiaster, a species with subtle sex differences in plumage and morphometry. Aims To explore variation in biometrics and their suitability to discriminate sex in adult European Bee-eaters Merops apiaster. Methods We sampled populations of a long-distance migratory species with low sexual

Capsule Different methods of comparing bill morphology between woodpecker species show different, but not contradictory results. Aims Differences among similar, closely related species which co-occur are still highly debated. In such a scenario, species should diverge morphologically to reduce competition. We studied this phenomenon, in three closely related woodpecker species that co-occur in eastern

We report detailed information about relatedness and parental investment in a communal nest in the Barn Owl Tyto alba. Two unrelated females laid their eggs in a single nest cup and successfully raised 4 nestlings out of 11 laid eggs. Apparently, the yearling female did not incubate the eggs and only occasionally hunted for the brood, in contrast to the older female which invested more effort in parental

Capsule There were no statistically significant differences in digit ratio between male and female chicks of the White Stork Ciconia ciconia. Aims To test the hypothesis that the ratio of digit lengths was related to sex in White Stork nestlings, and to explore the relationship between digit ratio and other biometrics. Methods We examined 101 White Stork chicks from a breeding population in western

Capsule: Wintering Water Rails Rallus aquaticus prefer small and narrow rivers, with large patches of wet emergent vegetation, and showed active response to playback, especially when they occurred in pairs. Aims: To investigate the habitat preferences and behaviour of Water Rails wintering in riverine ecosystems in eastern Poland. Methods: The study assessed factors driving the occurrence of Water

Capsule: A ten-year study of the causes of mortality in birds brought to a wildlife rehabilitation centre in Portugal, reveals that most deaths were due to trauma. Aims: This study aims to identify the main causes of morbidity and mortality in wild birds admitted to a wildlife rehabilitation centre in Northern Portugal, from 2008 to 2017. Methods: A total of 6058 records of admittance and necropsy

Population estimates of male Western Capercaillies Tetrao urogallus were carried out during the mating season using two methods: counts of singing males and non-invasive genetic analysis. Estimates of male numbers were 50% lower using the singing counts compared to the estimates obtained through genetic analysis, and underestimates were greatest when the number of Capercaillies was lowest.

The orientation of the nest entrances of 464 nests of the Rufous Hornero Furnarius rufus were explored in relation to vegetation cover along an altitudinal gradient in Argentina. There was no correlation between altitude and orientation for covered nests, since they were well protected from direct solar radiation, however, uncovered nests were orientated more towards the north with increasing altitude

Capsule: In comparison to other regions, the Common Snipe Gallinago gallinago in the Azores starts to display earlier and for a longer part of the year, but the laying period, although it starts earlier, does not seem to differ much from that observed elsewhere. Nesting success seems similar to that observed in other populations. Aims: This study aimed to infer the breeding phenology, characterize

Capsule Within the UK’s largest lowland Eurasian Curlew Numenius arquata population, curlew preferentially nested on physically disturbed (treated) than undisturbed (control) grassland, and low nest survival rates were primarily attributable to predation by Red Fox Vulpes vulpes. Aims To inform conservation interventions for Curlew within semi-natural lowland dry-grassland landscapes. Methods Across

Capsule: Nest site selection of Black-bellied Sandgrouse Pterocles orientalis in an Algerian arid environment is dictated by a combination of topography, human presence, landscape and space. Aims: To disentangle the drivers affecting Black-bellied Sandgrouse nest habitat use in an Algerian arid environment. Methods: We used data on a series of topographic, anthropogenic, landscape and space variables

Capsule: Wintering Ruddy Turnstones Arenaria interpres occur in higher densities and their populations decline less on, or close to, offshore refuges than on mainland sites subject to greater levels of human disturbance. Aim: To compare wintering densities of Ruddy Turnstones and changes in counts across time from sites with differing levels of human disturbance. Methods: Long-term counts of Ruddy

Capsule: Our findings regarding Hen Harrier Circus cyaneus territory site selection and breeding success in Ireland offer an opportunity for the development of initiatives and conservation actions aimed at enhancing the suitability of upland areas for breeding Hen Harriers and ensuring the long-term persistence of the species. Aims: To investigate landscape-scale associations between habitat composition

Capsule: Distance sampling identified an increase in estimated population size of Common Buzzards Buteo buteo in central southern England between 2011 and 2016 of more than 50%. The rate of population growth slowed in later years. Aims: To assess the utility of a targeted distance sampling protocol to derive seasonal and annual population estimates for Common Buzzards across an area of southern England

Capsule: Great Black-backed Gulls Larus marinus breeding on Skokholm, UK, fed predominantly on seabirds, rabbits, refuse, and marine prey, with the majority of pairs being dietary generalists, but with some specialist pairs. Aims: To understand the significance of Great Black-backed Gulls as top predators on a small offshore island with internationally important numbers of breeding seabirds (Skokholm

Capsule: In Egyptian Vultures Neophron percnopterus, both sexes invested similar parental effort throughout the breeding period. However, there was variation in the degree of intensity of parental care during some stages of the breeding period, suggesting that sex-role specialization exists for some activities. Aims: To quantify parental care behaviour of Egyptian Vultures for the first time and to

Capsule: In large and medium wetlands with extended reed beds Phragmites and cattail Typha dominated areas, Water Rails Rallus aquaticus and Little Crakes Zapornia parva show higher differences in nesting sites in contrast with other populations from small and fragmented wetlands, where the ranges of values for environmental variables at nesting sites overlap greatly. Aims: To investigate the nesting

Capsule: The undulating display flight of Golden Eagles Aquila chrysaetos has a territorial function on current consensus: we found that displays could occur at any location within a home range of territorial birds and were not more frequent at the territorial limits (as documented by a previous study) or around the nest site. Aims: To test the null hypothesis that display activity does not spatially

Capsule: Collective roosting behaviour of the Cattle Egret Bubulcus ibis was influenced by the weather and the season. Aims: To document the roosting behaviour of the Cattle Egret and assess the relationship between weather conditions and four components of the roosting behaviour including the population size, duration of roost occupancy, the timing of roost gathering and the rate of arrival at roost