Major roads have a negative impact on the Tawny Owl Strix aluco and the Little Owl Athene noctua populations

Abstract. The increasing road networks threaten ecosystems by direct effects such as increased mortality due to collision with vehicles and by various indirect effects leading to road avoidance. We censused Tawny Owls Strix aluco and Little Owls Athene noctua in 2005, 2007 and 2009 in a rural landscape in Southern Portugal in order to study the effects of roads and habitat characteristics on Tawny Owl density and Little Owl presence. The presence of both owl species in the 70 census locations was coherent among years. Our results showed that Tawny Owl density near major roads was lower, with the negative effects extending possibly up to 2 km. The probability of Little Owl presence was also negatively affected by the proximity to major roads. The negative effects of roads were significant even considering habitat preferences and spatial autocorrelation, which had the most marked effect on the density or presence of both owls. The reduced occupancy by Tawny Owls and Little Owls of habitats near major roads may be caused by several factors, including increased mortality, disturbance caused by high traffic density, and increased fragmentation. Traffic noise in particular may affect intra-specific communication and hunting efficiency. Consequently, habitat near roads may represent lower-quality territories for owls

Table of Content

oai:jurnal.ugm.ac.id:article/17788Table of Content Acta Cardiologia Indonesiana Volume 1 Number 1 Year 201

Song functions and territoriality in Eurasian Treecreeper Certhia fam iliaris and Short-toed Treecreeper Certhia hrachydactyla

Abstract. The study w as conducted in W estern Poland during three breeding seasons (1996)(1997)(1998). Spontaneous song rate changes and playback experiments were used to determ ine functions of the song in two closely related, sympatric species: Eurasian Treecreeper and Short-toed Treecreeper. Substantial differences in spontaneous song rate and reaction to playback betw een the studied treecreepers were found. On average Short-toed Treecreeper had a two times higher song rate and longer song bouts than Eurasian Treecreeper. Both species reacted stronger to the playback during the prebreeding and egg-laying stages than during the incubation/feeding stage. Therefore, the primary function of the song in these sibling species is to deter rival males from gaining access to the territory and fertile females. We found no evidence that the song was directly related to m ate attrachon or stimulation. W hen reacting to the playback the response patterns differed betw een the two species, but the overall experim ental song response w as similar. Interspecific differences in the singing pattern can be explained by dissimilar territorial behaviour. Short-toed Treecreeper bred in clusters, leading to frequent and m ore ritualized countersinging between rival males. Eurasian Treecreeper territories were scattered and separated by unoccupied habitat. This probably explains why the m ales rarely sing spontaneously, but behave more aggressively w hen rivals intrude

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Abstract. A large number of studies have demonstrated that habitat characteristics have a huge impact on all aspects of animal life history. This hypothesis predicts a relationship between habitat structure and the main components of fitness and, consequently, also predicts a relationship between habitat structure and other traits indirectly related to fitness, such as condition or health. We tested whether there was any relationship between the characteristics of a pine forest in the Iberian Peninsula and the condition of Great Tit nestlings reared in that forest. The parameters used to estimate nestling condition were weight, haematocrit and the presence of haemoparasites. The results suggest that mature forests produced nestlings in better condition but with a higher prevalence of haemoparasites than young forest, possibly because mature forests are a good habitat for both the bird and the parasite vector

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Abstract. Spatial patterns in bird community structure are closely related to changes in habitat composition at small spatial scales, but the explanatory power of habitat declines towards larger scales, where dispersal limitations and historical factors becoming more important. To disentangle these effects, we performed a large-scale bird census using a small-scale field approach in the Czech Republic. Using canonical correspondence analysis, we found that the strongest scale-independent gradient in bird community composition goes from higher-altitude forest assemblages to lower-altitude farmland and human settlement assemblages. The other gradients were also scale-dependent, probably due to the different distributional patterns of particular habitats at the respective scales. Closer examination of bird occurrence in particular habitats revealed that water bodies host the most distinct bird assemblage compared to the assemblages of other habitats. Interestingly, although the census tracked the most important east-west biogeographical gradient within the Czech bird fauna, we did not find longitude to be a significant predictor of changes in bird community structure along the transect at any resolution. We suggest that the biogeographical gradient is actually related to the habitat-based distinction between the coniferous-forested higher-altitude West and the deciduous-forested lower-altitude agricultural East. Fine-scale bird-habitat associations are thus responsible for the patterns of community structure at all spatial scales