Decreases in suitable habitat due to loss and fragmentation on the African non-breeding grounds are believed to be a driver of the declines in Palaearctic migrants. However, the effects of habitat loss and fragmentation on individual migrants have rarely been investigated. The European Honey-buzzard Pernis apivorus, a migratory forest specialist, displays the characteristics of a species that would be sensitive to declines in suitable habitat. We assessed site fidelity, habitat selection and home range characteristics of 32 tracked European Honey-buzzards in Africa to understand how habitat transformation on the non-breeding grounds affects the movement behaviour (particularly habitat use and home range characteristics) of the species. Adults had greater site fidelity than juveniles, indicating that young birds were exploring to locate suitable habitat for future non-breeding territories. Besides site fidelity, there were few significant differences between the movements of adult and juvenile Honey-buzzards. Birds of all age classes strongly selected treed habitat, as expected. Treed largest patch index and edge density had a negative effect on home range size, demonstrating that Honey-buzzards rely on large tracts of continuous forest, but can tolerate some level of fragmentation. Individuals with larger home ranges due to greater levels of forest fragmentation moved greater daily distances. In addition, Honey-buzzards spent more time in home ranges with larger treed largest patch indices and lower edge density. This reveals that birds that do not have access to a large patch of unfragmented forest are both flying greater distances on a daily basis and moving to new home ranges more often. This likely results in greater energy expenditure over their non-breeding period, which may have adverse effects on their long-term survival. Furthermore, our analyses support the hypothesis that continuing forest loss in Africa will have a negative effect on the European Honey-buzzard population.

Artificial fishponds are assumed to be suitable alternative habitat for many waterbirds including fish-eating predators such as herons. However, fish farming may lead to contrasting consequences for birds breeding in these biotopes and act as an ecological trap. I examined nestling diet and reproductive success of the least studied heron species in Europe, the endangered Little Bittern Ixobrychus minutus, at two fishpond complexes in south-western Slovakia. A total of 95 breeding attempts by this species were recorded during 2015–2019 in the study area, 84% of which produced at least one nestling. Despite relatively high nest success at both sites, the number of fledged nestlings differed significantly between the two fishpond complexes. The observed differences were mainly caused by higher nest predation at one of the fishponds. The diet of nestlings also differed between study sites. While the food taken at fishponds that are used for intensive farming of Common Carp Cyprinus carpio contained significant proportions of insects (41%) and amphibians (14%), at fishponds used mainly for individual sport fishing, parents fed their nestlings exclusively fish. However, the total amount of food delivered to nestlings was similar at both fishpond complexes. This suggests that Little Bitterns are able to adapt to fishponds with various intensities of management. Nevertheless, considering differences in nest predation risk between studied fishponds, other factors such as abundance and structure of littoral vegetation and predator abundance, can influence the breeding success of this species in artificial fishpond habitats. Identifying such factors may be important for the conservation and management of this species.

The use of Autonomous Recording Units (ARUs) for wildlife monitoring has increased in recent years. Acoustic monitoring has been used for a wide range of research topics, but it has rarely been used for monitoring wildlife migrations. In this work we evaluate the use of acoustic monitoring to characterise the diurnal migration pattern of a bird species, the European Bee-eater Merops apiaster. We set up 3–4 acoustic monitoring stations daily from 11 August to 21 September 2017 in north-eastern Spain, during post-breeding migration of the species. We used the Vocal Activity Rate (VAR), defined as the number of calls per unit time, as an index of Bee-eater abundance to describe the daily and seasonal migration pattern of the species. We also assessed the relationship between daily mean VAR estimated by ARUs, with citizen science data uploaded to the platform Ornitho.cat over a large spatial scale. According to mean VAR, intensity of migration increased weekly until the last week of August when it peaked, with species abundance decreasing to the lowest values in the study area by late September. A significantly higher number of calls was detected in the first and last hours of the day. Our results agree with previously published seasonal and daily migration patterns described for the species. VAR was significantly, positively correlated with the percentage of citizen science records of Bee-eater uploaded to complete checklists, used as an independent source to compare migration timing. Overall, our results, validated through citizen science data, show that acoustic monitoring can effectively provide complementary data for monitoring the bird migration of vocally active species. The use of ARUs may help to improve our understanding of migratory behaviour and be useful for a wide range of purposes.

Important biological parameters, such as movement and survival, can differ substantially between sexes, driving the demographic patterns of a population. Sex-dependent spatial segregation at the foraging grounds can evolve as a mechanism to reduce competition for resources between sexes, among other causes. Investigating such segregation, especially in scenarios of decreasing food availability, can contribute to understanding how birds adapt to a fast-changing world. The aim of the present study was to determine whether year-round movements and survival varied between sexes within a resident Yellow-legged gull Larus michahellis population. To this end we used live encounter data on colour-ringed Yellow-legged Gulls in northern Spain in the period 2009–2017. We used Generalized Linear Models to analyse distance to the colony of origin and multi-state models to estimate both survival and year-round movements, which did not provide evidence supporting an effect of sex on movement and survival. In contrast, distances travelled from the natal colony varied between seasons and all gulls were more likely to move greater than 100 km from natal sites. Juveniles showed lower survival rates (0.55) than older birds (0.90). Future research with GPS data might help to reveal, if existing, the occurrence of local spatial segregation between sexes that otherwise remains undetected.

Identifying the factors that influence nest survival insympatric species is important for the proper and effective management of their breeding populations. We used logistic-exposure models to estimate the daily survival rate and evaluate habitat traits, such as characteristics of trees supporting nests, position of nest in a tree, nesting micro- and macrohabitat, nest timing and weather, that may affect nest survival in Date Palm plantations in Biskra, Algeria. We monitored 68 Laughing Doves Spilopelia senegalensis, 65 Eurasian Collared Doves Streptopelia decaocto and 92 European Turtle Doves Streptopelia turtur nests during the 2019 breeding season. Our results showed that daily survival rate was positively associated with nest age for Laughing Dove and Eurasian Collared Dove, whereas a cubic trend was found for European Turtle Dove. Furthermore, daily survival rate of Laughing Doves was associated negatively with nest height and positively with distance to cereal crops. The beginning of the incubation phase is a critical period for nest survival in the three sympatric Columbidae species. However, in the European Turtle Dove, a second period of vulnerability was recorded between the end of the incubation phase and the beginning of the nestling phase, i.e. between day 11 and 18 of the 30-day nesting cycle. Overall, the highest daily survival rates were recorded for Laughing Doves (0.970 ± 0.006 SE) and European Turtle Doves (0.960 ± 0.005), whereas the lowest (0.937 ± 0.004) was found for Eurasian Collared Doves. Laughing doves and, to a lesser degree, European Turtle Doves are better adapted to conditions prevailing in North African Date Palm plantations. Nevertheless, to enhance dove reproduction, management focusing on ensuring the availability of food, water and suitable nesting trees should be undertaken.

Avian obligate brood parasitism is a specialised life history strategy that may impact the dispersal of juvenile and adult parasites when compared with non-parasitic (parental) bird species. In contrast to expectations, however, several brood parasites show a territorial spacing system while breeding, including breeding site fidelity within and across years. In comparison, data are sparse on the extent of natal philopatry in brood parasites. We estimated minimum levels of breeding site fidelity and natal philopatry in the generalist parasitic Brown-headed Cowbird Molothrus ater in two subsequent years of colour-ringing known-sexed adults and nestlings. Adults' breeding site fidelity was moderate and similar to previous reports on this species and on other non-parasitic temperate zone passerines. We recorded lower estimates for natal philopatry compared to adult Cowbird breeding site fidelity, but this still fell within the range typically reported for offspring of other North American, migratory, and parental songbirds. These results suggest that social parasitism as a reproductive strategy does not in itself appear to impact patterns of philopatric behaviours of Brown-headed Cowbirds and perhaps other brood parasites.

The White-vented Storm-petrel Oceanites gracilis is one of the world's least known seabirds and is listed as Data Deficient by the IUCN. To date, only one breeding colony, with less than ten pairs, is known from the Chungungo Islet in Chile. To understand the breeding habitat and the threats faced by the species, it is crucial to search for other colonies. We carried out field surveys of this species in the Atacama Desert between 2013 and 2020, searching for nests along c. 870 km of coastline, from sea level to 1700 m.a.s.l. We also revisited the breeding colony at the Chungungo Islet. To detect nests, we used endoscopic cameras and scent-trained dogs. We found two new breeding colonies in Pampa Hermosa and Pampa del Indio Muerto in the Atacama Desert, and additionally, we found two non-active breeding sites in Tocopilla and Sierra Miranda. Colonies were on different substrates, including crevices in saltpetre formations, gypsum and rocks (only Chungungo Islet). The threats identified for each breeding site include light pollution and habitat destruction by mining and energy projects. Further surveys are needed to estimate the population size and to assess the conservation status of this species.

The Black-faced Ibis Theristicus melanopis builds numerous nests in some trees but avoids others, suggesting that particular attributes of trees are selected for. In this study we test the hypothesis that the number of primary stems rising from the trunk correlates positively with the number of active nests in this colonial nesting species. Within an area of 61 km² of pastures in southern Chile, in 2017 we selected 96 isolated trees. For each tree we examined nest presence and breeding status. Of the total number of trees examined, 38 had active nests. The active nests were built solely in Patagonian Oak Nothofagus obliqua and Chilean Laurel Laurelia sempervirens. The nests were mainly located on branches of the primary stems, at an average height of 13.87 ± 0.62 m (±SE; range: 2–27 m). The average number of active nests per tree was 0.82 ± 1.13 (range: 1–4 nests) and did not vary significantly between the two tree species. However, average nest height was significantly greater in the Patagonian Oak than in the Chilean Laurel. Partial least squares structural equation modelling (PLS-SWM) indicated that tree structure, determined by tree age and canopy height, canopy cover and concealment, contributed to explaining the number of active nests in the trees. There was no relation between the number of primary stems and the number of active nests. We conclude that the Black-faced Ibis responded to the general tree architecture when nest building and that, probably, the presence of an active nest in a given tree constitutes key intraspecific information that induces other individuals of the population to build their nests in the same tree.

For five consecutive years (2001–2005), during a one-month period in August–September, we studied the turnover of juvenile Ruddy Turnstones Arenaria interpres at a tidal area along the Dutch coast, by colour-marking cohorts of migrants. Taking turnover into account revealed that 1.8–2.4 times as many juvenile birds used the area during their southward migration, compared to the numbers based on maximum counts. This larger estimate amounts to 35% of the number at which the 1% criterion of the Ramsar Convention is met, whereupon a wetland is designated as internationally important, with significant implications for conservation commitments. Presuming adult birds had the same turnover factor, adult birds contributed almost 70% to the 1% criterion during the same period. Autumn migration of juvenile Ruddy Turnstones was rapid, with more than 50% of individuals leaving within 4 days (95%-CI: 3.4–4.6). The mean mass at departure, as derived from median staging duration and mean body mass gain from recaptured birds (1.1 g/d), was 104.3 g (±10.3 SD). The mean potential flight range as calculated using the aerodynamic approach by Pennycuick was 1981 km (±717 SD), which suggests that juvenile birds that leave the area can cover short to medium distances at most. The fuel loads are sufficient to reach one of the four key wintering sites along the coast of France, but not the Banc d'Arguin in Mauretania, which is the first key wintering site in West Africa. By early October, 80% of the birds had left the study area. Our study shows the importance of a small tidal area during autumn migration and raises the question of whether a considerable number of comparable small stopover sites along the coast of Western Europe and West Africa are needed. More attention to the designation and the protection of such sites and the achievement of a network would have the potential to greatly support juvenile birds on their first journey south.

Migrant water birds such as Black Storks Ciconia nigra have progressively started capitalizing on man-managed ecosystems during migration. Behavioural and ecological studies at stopovers are thus key to deliver comprehensive conservation policies. To be able to improve stopover potential for one of the main Black Stork fall passage sites in central Romania, the Dumbrăviţa fishing complex, we analysed the species' foraging behaviour in relation to management of water levels and human activities. Afternoon feeding sessions were recorded weekly during two consecutive autumn migration periods in August–September 2017 and 2018. We used focal and scan sampling methods to quantify behavioural patterns based on 168, 10-minute feeding bouts between 16:00 and 18:00. The selection of foraging areas was contingent upon drainage practices and biased towards vegetated sectors of ponds. The time at which the storks started foraging was strongly correlated with the cessation of the daily fish harvest. Hunting strategies involved grabbing (visual) and water probing (tactolocation), the first prevailing in terms of frequency and time allotment and the latter mainly being used in shallow, muddy areas. Until now, traditional fish farming has unintentionally catered to Black Stork feeding preferences. We put forward several long-term management suggestions to secure the stopover potential for Black Storks at Dumbrăviţa.