Mongolian Lark as an indicator of taxonomic,functional and phylogenetic diversity of steppe birds

Biodiversity is declining at an unprecedented rate.Many grassland species have been lost and are now of conservation concern.Identifying efficient biodiversity indicators is a key pillar of the global conservation strategy.Mongolian Lark(Melanocorypha mongolica) is a charismatic bird species abound in Mongolian steppes,and recent studies demonstrated that this species share similar habitat requirements an d likely co-occur with other grassland birds.We tested the hypothesis that Mongolian Lark would make a suitable indicator for different aspects of avian biodiversity.We made a large-scale bird survey in Inner Mongolia,and classified point counts into three groups based on different taxonomic,functional,and phylogenetic biodiversity measures.We identified species indicators of each group using the indicator value(IndVal) analysis,and examined the bird compositional difference among groups.Linear models were used for studying the patterns of occurrence of Mongolian Lark in relation to various biodiversity measures.Mon golian Lark showed the highest indicator value in comparison with other potential species indicators.Bird species richness is significantly higher at sites with Mongolian Lark,an d its occurrence was negatively correlated with species abundance,functional richness,Rao’s quadratic entropy and phylogenetic diversity.Mongolian Lark is therefore a suitable indicator species for avian biodiversity in Mongolian steppes.It is highly distinctive in flight and usually seen singly.The widespread distribution and charismatic appearance make it easy to monitor and adequate for citizen science,and may provide useful information on the paradigm of surrogacy in conservation ecology.

A tale of two tails:asymmetry in Great Grey Shrike(Lanius excubitor)

Background: Asymmetry in the wild is a controversial, and to date, unresolved subject.Fluctuating asymmetry(FA) is the developmental instability(intra-individual variation) while, directional asymmetry(DA) expresses the asymmetry of the population mean.Methods: We analysed 63 Great Grey Shrike(Lanius excubitor) skins at the Naturalis Biodiversity Center, Leiden, the Netherlands.The black markings on the tails were digitized in order to evaluate the symmetry of the two sides of each shrike.Ptilochronology helped understand if nutritional condition affected symmetry.Results: ANOVA revealed no significant differences in size of the tail between sexes(F = 1.67, p > 0.05).However, there was significant difference in the shape of the black area in feathers between the sexes(F = 2.14, p < 0.05), and males had more elongated and slender black areas.Further, DA was observed only in males, but FA was noted in both sexes.Spearman correlation showed no significant association between FA score and tail features in both the sexes.However, in females, we observed a negative significant correlation between the number of fault and growth bars.The shape of the black area in the tail displayed no statistically significant association with the tail features in both sexes although growth bars influenced tail shape more than the number of fault bars.Conclusions: We concluded that the characteristics discovered by us need to also be checked in the field and if they can be used to sex individuals.Also, chromatic manipulative studies are require to verify if DA influences sexual selection in the Great Grey Shrike.

Food preferences by birds using bird-feeders in winter： a large-scale experiment

Background: Intentional winter bird feeding in gardens is one of the most common interactions between birds and humans. Because feeding may have both desired effects(provisioning of nutritious food for under-nourished birds) and undesired effects(favouritism of competitively superior species, transmission of disease), management of supplementary sites should be optimized from an ecological and conservation perspective. Therefore, the main aim of this study was to experimentally test winter food preferences of birds, with underlying potential influence of habitat(rural vs. urban) on realised food preferences pattern.Methods: We conducted an experimental analysis of food preferences of wintering birds by provided bird-feeders in urban and rural environments across Poland. Data were collected twice during winter 2013–2014 across Poland, in total with 80 experimental trials.Results: Sunflower seeds were the most preferred food supplement both in urban and rural habitats, significantly more exploited than any other food simultaneously available in feeders(animal fat, millet seed and dry fruits of rowanberry). However, no significant differences were recorded between urban and rural habitats in use of food.Conclusions: The degree of use of a particular type of food at bird-feeders depended on the overall use of food in a bird-feeder—consumption of each of the four types of food was significantly positively correlated with that of the others, and it was positively correlated with the number of birds observed at the feeders.

Prey reduce risk-taking and abundance in the proximity of predators

Prey have evolved anti-predator defences that reduce or eliminate the risk of predation. Predators often reproduce at specific sites over many years causing permanent threats to local prey species. Such prey may respond by moving elsewhere thereby reducing local population abundance, or they may stay put and adjust their behavior to the presence of predators. We tested these predictions by analyzing population abundance and anti-predator behavior within 100 m of and 500 m away from nests of sparrowhawks Accipiter nisus and goshawks A. gentilis for 80 species of birds. Population abundance of prey was reduced by 11% near goshawk nests and by 15% near sparrowhawk nests when compared with nearby control sites in similar habitats. Flight initiation distance （FID） of prey, estimated as the distance at which birds took flight when approached by a human, increased by 50% in the presence of hawk nests, providing evidence of adjustment of anti-predator behavior to prevailing risks of predation. Susceptibility to predation was estimated as log transformed abundance of the observed number of prey items obtained from prey remains collected around nests minus log transformed expected number of prey according to point counts of breeding birds. FID increased from 10 to 46 m with increasing susceptibility of prey species to predation by the goshawk and from 12 to 15 m with increasing susceptibility of prey species to predation by the sparrowhawk. These findings suggest that prey adjust their distribution and anti-predator behavior to the risk of predation.

Habitat preferences of two sparrow species are modified by abundances of other birds in an urban environment

Every species has certain habitat requirements, which may be altered by interactions with other co-occurring species. These interactions are mostly ignored in predictive models trying to identify key habitat variables correlated with species population abundance/occurrence. We investigated how the structure of the urban landscape, food resources, potential competitors, predators, and interaction between these factors influence the abundance of house sparrow Passer domesticus and the tree sparrow P. montanus in sixty 25 ha plots distributed randomly across residential areas of the city of Pozna5 （Poland）. The abundance of the house sparrow was positively correlated with the abundance of pigeons but negatively correlated with human-related food resources. There were significant interaction terms between abundances of other urban species and habitat variables in statistical models. For example, the abundance of house sparrow was negatively correlated with the abundance of corvids and tree sparrows but only when food resources were low. The abundance of tree sparrows positively correlated with density of streets and the distance from the city center. The abundance of this species positively correlated with the abundance of corvids when food resources were low but negatively correlated at low covers of green area. Our study indicates that associations between food resources, habitat covers, and the relative abundance of two sparrow species are altered by the abundance of other urban species. Competition, niche separation and social facilitation may be responsible for these interactive effects. Thus, biotic interactions should be included not only as an additive effect but also as an interaction term between abundance and habitat variables in statistical models predicting species abundance and occu rrence.

A biotrophic fungal infection of the great burnet Sanguisorba officinalis indirectly affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius

Interactions between ecological communities of herbivores and microbes are commonly mediated by a shared plant. A tripartite interaction between a pathogenic fungus-host plant-herbivorous insect is an example of such mutual influences. In such a system a fungal pathogen commonly has a negative influence on the morphology and biochemistry of the host plant, with consequences for insect herbivore performance. Here we studied whether the biotrophic fbngus Podosphaera ferruginea, attacking the great burnet Sanguisorba officinalis, affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius. Our results showed that the pathogenic ftmgus affected the number and size of inflorescences produced by food-plants and, more importantly, had in direct, plant-mediated effects on the abun dance, body mass and immune response of caterpillars. Specifically, we found the relationship between caterpillar abundance and variability in inflorescence size on a plant to be positive among healthy food-plants, and negative among infected food-plants. Caterpillars that fed on healthy food-plants were smaller than those that fed on infected food-plants in one studied season, while there was no such difference in the other season. We observed the relationship between caterpillar immune response and the proportion of infected great burnets within a habitat patch to be positive when caterpillars fed on healthy food-plants, and negative when caterpillars fed on infected food-plants. Our results suggest that this biotrophic fungal infection of the great burnet may impose a significant indirect influence on P. teleius caterpillar performance with potential consequences for the population dynamics and structure of this endangered butterfly.

Not so black,not so white:differences in microorganism load of contiguous feathers from white stork chicks

Many organisms are characterized by strikingly contrasting black and white coloration,but the function of such contrasts has been inadequately studied.In this article,we tested the function of black and white contrasting plumage in white stork Ciconia ciconia chicks.We found greater abundance and diversity of microorganisms on black compared with adjacent white feathers.In addition,nest size was positively correlated with the abundance and diversity of microorganisms on white feathers.Flight initiation distance(FID),defined as the distance at which adult white storks took flight when approached by a human,was negatively correlated with most measurements of microorganism abundance.Breeding success was generally positively correlated with the abundance and diversity of microorganisms on black feathers.The feather growth rate was positively correlated with some and negatively correlated with other measurements of microbial abundance and diversity.Finally,chick growth was negatively correlated with the number of microbial species on black feathers and positively with the abundance and diversity of microorganisms on white feathers.These findings are consistent not only with the role of microorganisms in the maintenance of a benign microbial environment which differs between black and white feathers,but also with the hypothesis that several taxa of microorganisms found in black and white plumage are virulent,with negative effects on the fitness of their hosts.