DNA diet profiles with high‐resolution animal tracking data reveal levels of prey selection relative to habitat choice in a crepuscular insectivorous bird

Given the global decline of many invertebrate food resources, it is fundamental to understand the dietary requirements of insectivores. We give new insights into the functional relationship between the spatial habitat use, food availability, and diet of a crepuscular aerial insectivore, the European Nightjar (Caprimulgus europaeus) by relating spatial use data with high‐throughput sequencing (HTS) combined with DNA metabarcoding. Our study supports the predictions that nightjars collect a substantial part of their daily nourishment from foraging locations, sometimes at considerable distance from nesting sites. Lepidopterans comprise 65% of nightjars' food source. Nightjars tend to select larger species of Lepidoptera (>19 mm) which suggests that nightjars optimize the efficiency of foraging trips by selecting the most energetically favorable—larger—prey items. We anticipate that our findings may shed additional light on the interactions between invertebrate communities and higher trophic levels, which is required to understand the repercussions of changing food resources on individual‐ and population‐level processes

Multi-scale habitat selection throughout the annual cycle of a long-distance avian migrant

Long-distance migrants are constrained by widely separated hospitable habitats in geographically isolated locations, making them vulnerable to environmental change, both through natural and anthropogenic causes. Knowledge about their resource selection decisions is imperative to understand the drivers of their declines. The distinct periods within an annual cycle, when individuals experience different environmental circumstances, are inextricably linked through carry-over effects which can have important consequences for the individual, and consequently the population. In this study, we employ precise archival GPS-tracking data of European Nightjars (Caprimulgus europaeus) and high-resolution global land cover data to examine habitat selection during the sedentary wintering and breeding periods, as well as during autumn and spring migration, using a correlational approach. We demonstrate how nightjars use general habitat characteristics, such as landscape diversity, for high-order habitat selection, while resource selection at a finer spatial scale is reliant on fine-scale variables related to a habitat’s suitability, such as surface area of grassland and shrubland. We show that nightjars favour spatially diverse landscapes, which allows them to minimize time spent searching for optimal habitats. The considerable variation in the drivers of habitat selection between and within seasons shows how anthropogenic land-use change can have an array of different impacts on migrants by influencing large- and fine-scale habitat selection. This study shows the advantages of an individual based GPS-tracking approach, combined with high spatial resolution remote sensing data, and highlights the need for full annual-cycle research on scale dependent habitat selection of long-distance avian migrants

Data from: Study on the foraging behaviour of the European nightjar Caprimulgus europaeus reveals the need for a change in conservation strategy in Belgium

Effective nature conservation requires coherent actions based on the best available evidence concerning protected species. Recent studies have suggested that European nightjars Caprimulgus europaeus forage outside their recognized breeding habitats, yet, for Flanders (northern Belgium) information on nightjar foraging behaviour and key foraging habitats is lacking. To assess whether the foraging ecology of nightjars in Flanders is similar to that observed in other parts of Europe, we studied the crepuscular behaviour of this species in Bosland (northeastern Flanders) during a five-year radio telemetry study. Tracking of 48 individuals within a coniferous forest was standardized and home ranges were calculated using a kernel density estimator (fixed kernel). Habitat use was investigated by comparing kernel placement to available habitat. Average maximal foraging distance was 2603 ± 1094 m and home ranges extended up to 691 ha. We identified the key foraging habitats to be extensively-cultivated grasslands and recreational areas, areas that were previously assumed unsuitable for Belgian nightjars. Our results indicate the importance of foraging sites outside the breeding territory, confirming the findings of previous studies performed elsewhere in Europe. Incorporating our findings into future conservation plans could, therefore, lead to improved efficiency of EU conservation measures, designed for the protection of this bird species in Flanders

Nightjar diversity and microhabitat use in Nechisar National Park, Ethiopia

<p>Knowledge of the distribution and ecology of East African nightjars is, to a large extent, unknown. We collected ecological information on the diversity and microhabitat use of nightjars in Nechisar National Park in January 2015 by executing field captures and observations. We also attempted to find a live specimen of the Nechisar Nightjar <i>Caprimulgus solala</i>. During the course of 18 nights we observed five nightjar species, captured 49 individuals and observed that nightjars were closely associated with protective landscape elements. In spite of the intensity of our survey, we were not able to find a living specimen of the Nechisar Nightjar, which could indicate the species is either migratory or extinct.</p

Winter agri-environment schemes and local landscape composition influence the distribution of wintering farmland birds

Since 1992, the European Union puts in place agri-environment schemes (AES), such as unharvested set-aside fields with winter bird crops (WBC), to counteract farmland biodiversity declines that are associated with agricultural intensification since the second half of the 20th century. These measures aim at, among other things, improving habitat quality and food availability for farmland birds throughout the year. In this study in Dry Hesbaye, an agricultural region in eastern Flanders (Belgium), we use spatial generalized linear mixed models to investigate how species richness and the observation probability of ten bird species with different food diets are associated during winter (November - March) with WBC implementation in arable crop fields and the presence of landscape elements within 50 m of these fields. Our results show that species richness and the observation probabilities of nine out of ten wintering farmland bird species under study are increased at crop fields with WBC implementation. Species richness and observation probabilities are also associated with the presence of nearby landscape elements such as hedgerows, woodland, unpaved roads, or grass margins. We conclude that unharvested set-aside fields promote local diversity and observation probabilities of most of the species under study. In addition, AES measures should be implemented after considering the aforementioned natural or semi-natural nearby landscape elements, which also influence local diversity and species’ observation probability