Search results for "Birds"
showing 10 items of 291 documents
Prevalence of Listeria sp. in droppings from urban rooks (Corvus frugilegus)
1997
Droppings from 112 urban rooks (Corvus frugilegus) were cultured for the presence of Listeria sp. Overall, 46% of rooks sampled harboured one or more Listeria species. Of all birds examined, 33%, 24% and 8%, respectively, were infected with Listeria monocytogenes, Listeria innocua and Listeria seeligeri. Differentiation of L. monocytogenes and L. seeligeri carried out by several phenotypic typing methods proved the diversity of strains and the major role of rooks which widely contribute to spreading this bacteria in our environment. The results also suggest that the ability to recover specific Listeria strains from the same sample is at least partially dependent on the methodology. These fi…
Different trends of neighboring populations of Lesser Kestrel: Effects of climate and other environmental conditions
2019
The sensitivity of population trends to the climate and environment is generally considered a species-specific trait. However, evidence that populations may show different responses to the climate and environmental conditions is growing. Whether this differential sensitivity may arise even among neighboring populations remains elusive. We compared the trends of two neighboring populations of the Lesser Kestrel Falco naumanni, using data from a 12-year survey of 158 colonies in Sicily, Italy; the two populations inhabiting a lowland and an highland area, respectively. Population trends were modeled through the TRIM algorithms implemented in R (package rtrim). A reversed U-shaped population t…
House martin Delichon urbicum
2018
unusual breeding location
Floral Diversity and Pollen Transfer Mechanisms in Bird-pollinated Salvia Species
2007
† Background and Aims Bird-pollinated (ornithophilous) Salvia species (sages) transfer pollen either by means of a staminal lever mechanism or by immovable stamens. As the distribution of the two modes within the genus is not known, we present a survey of all ornithophilous sages. The main focus is given to floral diversity especially with respect to functional lever morphology. Thereby the hypothesis is tested that, due to a pollinator shift from bees to birds, the lever mechanism became unnecessary. † Methods To get a general idea about the diversity of pollen transfer mechanisms, 186 ornithophilous Salvia species were classified according to the functional morphology of the stamen and th…
Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots
2015
Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits ( Parus major ) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, wi…
Climate-driven changes in winter abundance of a migratory waterbird in relation to EU protected areas
2015
AimSpecies are responding to climate change by changing their distributions, creating debate about the effectiveness of existing networks of protected areas. As a contribution to this debate, we assess whether regional winter abundances and distribution of the Smew Mergellus albellus, a migratory waterbird species listed on Annex I (EU Birds Directive) that overwinters exclusively in European wetlands, changed during 1990-2011, the role of global warming in driving distributional changes and the effectiveness of the network of Special Protection Areas (SPAs, EU Birds Directive) in the context of climate change. LocationEurope. MethodsWe used site-specific counts (6,883 sites) from 16 countr…
Ecomorphological predictors of natal dispersal distances in birds.
2008
1. Dispersal is one of the key ecological parameters but it is very difficult to quantify directly. As a consequence, empirical studies often ignore dispersal or use indirect measures. 2. Ringing data have previously been used to estimate the natal dispersal distances of 47 British passerine bird species. This provides an excellent opportunity to examine the potential of various indirect measures to predict natal dispersal distances in British birds. 3. We use a phylogenetic comparative framework and single- and multipredictor models including ecomorphological, behavioural or ecological traits to predict natal dispersal distance. 4. A multipredictor model that includes Kipp's distance (a me…
THE ENVIRONMENTAL IMPACT OF POWER LINES ON BIRDS IN SICILY
2018
Electrocution is a serious conservation problem worldwide for a large number of bird species (BEVANGER, 1994, 1998; BIRDLIFE INTERNATIONAL, 2004; PRINSEN et al., 2011). Due to its wide extension, it is necessary to seek methods that optimize the identification of the most dangerous pylons (JANSS and FERRER, 2001; MANOSA, 2001), lines and the highest risk areas (TINTÓ et al., 2010; GUIL et al., 2011). Actually, the data on bird mortality caused by electrocution and collision in Sicily are deficient, however, a preliminary study suggests that the White Stork (Ciconia ciconia L., 1758) is one of the most threatened species inside two Special Protection Areas (SPA) (ZAFARANA and BARBERA, 2016).…
Biotic homogenization of forest bird communities under human influence
2018
Human actions impact biodiversity worldwide. Specialist species are particularly sensitive to environmental degradation whereas generalists may even benefit from habitat changes. As a consequence, specialists are declining while generalists are increasing and, therefore, communities become more similar. This phenomenon is known as biotic homogenization. In boreal forests logging and forest management is the most important factor changing the native habitat. In this thesis I studied if human actions are homogenizing boreal forest bird communities. I further studied if protected areas can maintain their diversity and, thus, prevent homogenization. Through the individual studies, biodiversity …
Does Arsenic Contamination Affect DNA Methylation Patterns in a Wild Bird Population? : An Experimental Approach
2021
Pollutants, such as toxic metals, negatively influence organismal health and performance, even leading to population collapses. Studies in model organisms have shown that epigenetic marks, such as DNA methylation, can be modulated by various environmental factors, including pollutants, influencing gene expression, and various organismal traits. Yet experimental data on the effects of pollution on DNA methylation from wild animal populations are largely lacking. We here experimentally investigated for the first time the effects of early-life exposure to environmentally relevant levels of a key pollutant, arsenic (As), on genome-wide DNA methylation in a wild bird population. We experimentall…