ABSTRACT Counts at 16 Capercaillie leks revealed that singing started two hours before sunrise and reached a peak in the number that sang about one hour before sunrise. Most song had finished by sunrise, but some extended up to five hours after sunrise. The period of song was longer at leks where more males were seen and/or heard. Such field observations may be useful in interpreting data from unattended acoustic recorders.

ABSTRACT Capsule Azure-winged Magpies Cyanopica cyanus living in isolated plantations had higher nesting success away from habitat edges and lower breeding success away from conspecific nests. Aims The study aims to find the relationship between nest location and breeding success by measuring nest locations within two Azure-winged Magpie populations that breed in plantation environments with clear boundaries. Methods Two populations were selected in Gyeonggi-do, South Korea, with areas 11,392 m2 and 1,457 m2. These two plantations had a single species of tree, the Japanese Yew Taxus cuspidata, so breeding habitat was easily delineated. Breeding performance and breeding success were monitored daily. Distance between nests and distance to habitat edge were measured. Results Breeding success differed according to nest locations, and nests that were relatively distant from other neighbouring nests and that were closer to the edge of the breeding site had a higher risk of failure. Conclusions The results indirectly support Hamilton and Vine’s models, which assumed that individuals breeding close to the edge of the breeding group should have a higher risk of predation than those in the centre. It appears that the selection of nest location of Azure-winged Magpies may be affected by a social factor (i.e. colonial breeding in a cooperative breeding system) and an environmental factor (i.e. habitat edge effects).

ABSTRACT Capsule The Eurasian Griffon Vulture Gyps fulvus is an obligate scavenger relying on spatially and temporally unpredictable food resources. We demonstrate how high-frequency telemetry data can be efficiently used to identify vultures’ feeding locations in the wild and study their diet. Aims To study the Griffon Vulture diet composition, seasonal variations, and bathing frequency in an area with high natural food availability. Methods We used a remote-sensing technique based on GPS and accelerometry data to identify the feeding locations, and ground-truthing to identify the carcass species and investigate the causes of mortality. Results We identified 13 taxa in the diet of Griffon Vultures. Cattle comprised 48.5% of the diet, followed by sheep (24.3%), while wild animals were 13.1%. We observed seasonal variation in the proportion of small stock and game species in the diet. Predation was reported as the main cause of mortality (60.2%) for prey species, while natural causes accounted for 37.6%. Vultures were mainly feeding in areas south of their breeding colonies in Bulgaria and Greece. Natural springs and fountains were regularly used by the Griffon Vultures for bathing and drinking, especially in the summer. Conclusions Free-ranging livestock creates favourable feeding conditions for vultures, especially in areas with rugged terrain and a high density of predators. An increase in the number of wild ungulates can potentially buffer the fluctuations in livestock numbers and be beneficial for vultures, especially in the autumn and winter months. Lead ammunition must be substituted with non-toxic alternatives to reduce the exposure of vultures and other scavengers to lead poisoning.

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 information on Water Rail abundance, distribution and habitat use on the island, and indicates that the species does not always require access to wet ground in winter.

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 and a warm, humid period. For each period, the mean nest entrance orientation and distribution were estimated and compared against a random orientation model. Results: A total of 42 nests were found during the first period of reproduction and 32 during the second period. In both cases, the mean orientation was non-random and significantly different between the two periods: nests were more likely to be orientated towards the northwest in the first period and to the east in the second period. Conclusions: Climate variation throughout the breeding season was reflected in differences in nest entrance orientation. This could be because this species takes advantage of solar radiation to increase the temperature within the nest during the first cold months of the breeding season and reduces the humidity of the nest, generated by intense rain, as the season progresses.

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 analysis that is often hidden from a reader (described here), so we refute that our results were caused by chance; (ii) we published a result based on an incorrect method in the revision process. We hope that other researchers involved in long-term projects involving large and complex datasets can learn from our mistake, as we will endeavour to do.

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 to evaluate the extent of predation on bird species of conservation concern. Methods: Prey remains were collected during nestling ringing from successful nests located in Lithuania. Results: The frequency of the prey groups varied along an environmental gradient, with a general pattern of increasing avian prey consumed by pairs breeding in areas with less abundant aquatic habitats. The frequency of alternative prey (i.e. terrestrial birds, mammals) and dietary niche breadth did not increase between 2005 and 2018 and during which time the White-tailed Eagle population nearly doubled. Instead, the occurrence of Northern Pike Esox lucius remains, which was the most frequent single prey species, increased throughout the study period. Bird species of conservation concern constituted only a small fraction of all the prey identified. Conclusions: The White-tailed Eagle has not become more dependent on alternative prey despite its population increase.

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 system located between two poles with a minimum height of 9.25 m and a maximum of 12.95 m, previously designed for catching bats. Once captured, the birds were ringed and fitted them with a remote download GPS tag, weighing 3.4 g. Results: Twenty individuals (17 adults and 3 juveniles) from 14 territories were captured during the 28 sampling days. All marked breeders continued with chick provisioning and in 12 of the territories were successful in fledging young. We found no significant difference in the number of fledglings between nests where the breeders were captured and tagged with devices (1.71 ± 0.19 se) and nests where the breeders were not captured (1.71 ± 0.29 se). The GPS tags allowed us to obtain a mean of 102.6 (±15.91 se) locations for each bird during a tracking period averaging 57.8 (±10.4 se) days. Despite the steep slope and the high forest canopy in the hábitat, 77.09% of GPS locations were accurate to within 20 m. Conclusion: Our results showed that this method allows us to obtain important information about the habitat use of this species during the breeding period without any apparent effect on reproductive success.

ABSTRACTAn analysis of the biometrics of 187 individually marked Red-crowned Crane Grus japonensis chicks from Japan revealed that larger chicks were more likely to seen alive in their first-winter. Male chicks were larger than females but sex did not influence apparent survival, nor did brood size determine body size.

ABSTRACTCapsule: Time-triggered camera traps and line transects were compared in order to identify advantages and limitations of multi-method studies for bird surveys.Aims: To test whether, compared to traditional line transects, the use of time-triggered cameras with a short trigger interval of 20 s is an effective method for monitoring farmland birds, and to provide a detailed description of this monitoring method.Methods: We set up camera traps in flower strips and field margins in the county of Rotenburg, Germany, during winter (2012/13, 2013/14), summer (2013) and autumn (2013). In order to assess the results of camera traps, we conducted a comparative study by using line transects at the same study sites.Results: In total, we observed 20 bird species by camera trapping and 20 species by line transects but only 14 of these species were observed with both methods. Combining both methods leads to a higher number of 26 species. In flower strips, however, significantly more species were recorded by line transects than by camera traps. On the other hand, in field margins, line transects and camera traps contributed equally, indicating the advantage of combining the methods.Conclusions: The combination of camera traps and line transects is recommended for more reliable recording of bird communities. This combination was particularly beneficial in study sites with low bird densities and bird activity, such as field margins. However, in order to achieve reliable bird detections using time-triggered camera traps, a short interval between the pictures is needed. The limiting factor of time-triggered camera traps is the time-consuming viewing of the recorded images. Nevertheless, the benefit is that it can be conducted independently of time and space and it is weather- and researcher-independent. Moreover, camera traps allow multi-hour observations and necessary fieldwork time is short.