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Vegetation structure and food availability can significantly modify the composition of farmland avifauna. In the 2006 breeding season we tested the effect of food resources (density of epigeic invertebrates) in two local habitats on foraging of farmland birds. We have been exploring how intensively the foraging birds utilise meadow and pasture habitats in an extensively used farmland area of Central Poland. Two plots were selected in adjacent meadow and pasture each of 0.18 ha where bird and invertebrate sampling was conducted in May 2006. We set five Barber traps active for two weeks at each plot to survey for the epigeic invertebrates which form the main part of farmland birds’ diet. In total, we trapped over two thousands invertebrate individuals (mainly Aranea, Coleoptera and Hymenoptera). Visual observations of foraging birds were performed from an elevated observation point located at a 25 m distance from the edge of the plots. We recorded 191 observations of foraging by 12 bird species (mainly Sturnus vulgaris L., Upupa epops L., Cuculus canorus L., Motacilla alba L., Corvus corone L., C. monedula L., Pica pica L.). We found that overall invertebrate density at the meadow was 2.5-fold higher than at the pasture. This was also the case with the invertebrate groups that were preyed upon by the birds. We recorded however a 10-fold higher frequency of foraging of birds at the pasture, as compared to the meadow. Preference of a bird species for foraging at the pasture was inversely correlated with its body mass. We discuss the importance of pastures for the preservation of farmland avifauna.
Preservation of foraging habitats is a fundamental approach to bat conservation. Yet, knowledge on the primary foraging sites of Mediterranean bats remains scarce, particularly during the summer when the availability of prey can be limiting. This study was designed to determine in which habitats bats forage in Southern Portugal, during this potentially stressful period. During the summers of 1994 and 1995, bat foraging activity was monitored in representative habitat types using an ultra-sound detector. The number of feeding-buzzes and bat-passes were counted and species identified through the analysis of recorded echolocation calls. None of the recorded species restricted its foraging activity to a single habitat type, but water sites were preferred by most bats. Tadarida teniotis was an exception to this habitat use. Further analysis confirmed that riparian habitats when surrounded by autochthonous broad-leaved forests seem to provide optimal foraging areas for bats during summer. Opposite, water sites within habitats resulting from intensive agriculture or forestry, provide very poor foraging areas. The typical Mediterranean landscape of Iberia, dominated by oak-woodlands and with numerous, scattered and well vegetated water sites, seems to grant optimal foraging habitat for bats during summer. However, this landscape is itself at risk. Current production demands are causing substantial land-use changes and, despite some European programmes on the preservation of Mediterranean oak woodlands and their biodiversity, the furtherance of this landscape is at stake. The preservation of traditional management strategies of oak-woodlands and associated water sites should be strongly encouraged.
To manage conservation issues, it is essential to recognize the factors determining the occurrence of endangered species. This study examined the foraging habitat and nest site preferences of the Lesser Spotted Eagle Aquila pomarina (Brehm) in the Knyszyńska Forest (NE Poland). This is a large (839 km²) protected (Landscape Park Puszcza Knyszyńska, NATURA 2000) forest complex composed mainly with coniferous and mixed wood stands with meadows in river valleys inside the complex and arable lands outside it. The research was carried out on a study plot of 440 km², in the breeding seasons of 2006 and 2007. Nest site characteristics, such as distance to open areas, settlements and watercourses were measured and compared with random points. The habitat composition of hunting territories was recorded and compared to habitat availability on the whole study plot, and the birds’ hunting effort was assessed. The eagles showed a preference for nesting close to open spaces (potential hunting grounds) and watercourses (like rivers and streams), but avoided proximity to human settlements. As hunting grounds, the birds highly preferred grasslands and avoided arable lands. Time spent hunting on grasslands comprised over 95% of the observed hunting activities and grasslands were significantly positively selected both in the whole study plot and within a 2 km-radius from nest. The results suggest that the conservation of the Lesser Spotted Eagle should focus especially on meadows and pastures adjacent to large forest complexes.
We hypothesized that the flight activity of bats in forests is higher in parts closer to edges due to the presence of species roosting in trees and foraging mostly outside as well as those coming to forage from outside. The aim of our study was to test this expectation using bat netting on roads in a forest belt 4–5 km wide in Kampinos National Park near Warsaw (central Poland). Tree stands were mostly coniferous. Ten full-night study sessions were done between the end of July and the beginning of September in the years 2007–2009. During each session, bats were netted at two sites situated in two zones designated as “edge” (100– 500 m from forest edge) and “interior” (1750–2250 m from forest edge). The study revealed twelve species, among which Eptesicus serotinus (Schreber), Nyctalus noctula (Schreber) and Barbastella barbastellus (Schreber) were by far most abundant. Total bat abundance recorded at ten pairs of netting sites differed significantly between the edge zone (ca. 2.5 times higher numbers) and the interior zone. Among individual species, a statistically important difference was shown only for Plecotus auritus (L.), which was more abundant close to the forest edge, though a similar tendency was noted in other species, mostly E. serotinus. The frequency of each species in the bat assemblage as well as species diversity of bats flying along forest roads did not differ between the two zones.
Land use changes occurring in Europe in recent decades are generating important changes in the forest landscape characteristics and are having important effects on avian species richness and abundance. This is particularly important for some bird species of particular conservation concern that require heterogenous landscapes where breeding habitats are proximal to foraging habitats. Among these birds, the European Turtle Dove Streptopelia turtur is particularly important because of its marked population decline. In southern Europe, forest landscapes have been considered important breeding areas for Turtle Doves. We assessed the influence of the foraging area characteristics — distance to cereal crops and wild seed species abundance — and water availability on Turtle Dove breeding habitat suitability in a Mediterranean forest landscape in southern Spain. Forty-six point locations were surveyed during the spring of 2014 and 2015 on two nearby farms of a forest protected area. The average local abundance of Turtle Doves found at each point location was 1.25 ± 1.31 males, and it was significantly higher at the point locations closest to cereal crops, as well as at nesting sites where the wild seed species included in its local diet were abundant, especially Echium plantagineum. Distance to water in the studied range (average distance 475 m) did not show a significant effect on Turtle Dove local abundance, although the high availability of water in the study area could have a positive influence on the overall Turtle Dove breeding habitat suitability. To benefit Turtle Dove breeding habitat suitability, cultivated areas with cereals/legumes near those forest areas where Turtle Doves reproduce should be promoted. Likewise, the promotion of those herbaceous species that are locally important in the Turtle Dove diet, available, for example, through specific grazing management, should be taken into account when nesting habitat restoration is designed in forest areas, regardless of whether the distances to food resources are long.
We determined the foraging habitats of the northern batEptesicus nilssonii (Keyserling et Blasius, 1839), Brandt’s batMyotis brandtii (Eversmann, 1845), whiskered batMyotis mystacinus (Kuhl, 1819), Daubenton’s batMyotis daubentonii (Kuhl, 1819) and brown long-eared batPlecotus auritus (Linnaeus, 1758) in southern Finland. Among these species, we compared the diversities of foraging habitats, linear feature preference and the bats’ tendencies to forage simultaneously.Eptesicus nilssonii was the most opportunistic, foraging in a wide range of habitats.Myotis daubentonii (94%) foraged mainly on water habitats, whileM. brandtii/mystacinus (89%) andP. auritus (66%) foraged mainly in forest habitats. The diversities of foraging habitats used byE. nilssonii andP. auritus were higher than those ofM. brandtii/mystacinus andM. daubentonii. Both E.nilssonii andP. auritus foraged mostly alone or in small numbers, whileM. brandtii/mystacinus tended to gather in large numbers to forage in the same habitat. Half ofE. nilssonii and 46% ofM. daubentonii foraged over linear features, while other species did not use linear features to such an extent. Management and conservation of foraging habitats are needed especially forM. brandtii/mystacinus andM. daubentonii, which are more specialized thanE. nilssonii and P. auritus.
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