Elevational Patterns of Blowfly Parasitism in Two Hole Nesting Avian Species

Climate change is predicted to cause shifts in parasite distributions, leading to encounters with new hosts. Mountains offer a natural experimental background to study how parasite distributions vary across climatic gradients. Parasite abundance is generally assumed to decrease with ascending elevation, as colder climates may preclude several parasites to complete their life cycles. The present study analyses the elevational variation in the prevalence and intensity of the blowfly Protocalliphora azurea found in the nests of two hosts—the coal tit (Periparus ater) and great tit (Parus major)—in Sierra Nevada (SE Spain). Protocalliphora azurea adults are free-living flies, while their larvae are nest-dwelling parasites that feed on nestling blood. In contrast to initial predictions, P. azurea larvae were less prevalent at lower elevations. In Mediterranean environments, the colder and damper climate of medium and high elevations might favour this parasite. Alternatively, greater anthropogenic perturbation in lowland environments may have a negative impact on the parasite. The findings also show that the two host species had similar parasite loads. As coal tits are half the size of great tits, this suggests that the coal tits were more severely parasitised. In conclusion, the generalised assumption that parasite abundance decreases with elevation does not hold true for the present case and elevational parasite patterns probably depend on specific host–parasite systems and climatic conditions in the mountains.

Changes in the breeding avifauna of Lviv residential part from the period since 2006 till 2018 years

The analysis of breeding avifauna changes has been performed on the base of field studies that took place in residential parts of the Lviv city in 2006-2007 and 2017-2018 breeding seasons. Nowadays 84 breeding species were recorded in the Lviv city. The number of local species in bird population significantly decreased from 51 in 2007 to 41 in 2018. It shows the reduction of some species number together with the growth of their diversity (from 73 to 81) and significant increase in population from 443,0 to 581,6 pairs/10 ha. During 12 years 70 species constantly remain in the fauna. Three species disappeared from nesting, and 11 had appeared. Seven of them appeared for the first time: Marsh Tit, Hooded Crow, Hoopoe, Little Bittern, White-backed Woodpecker, Stonechat, Coal Tit. Four came back to the city for nesting after absence in 2006-2007 years: Partridge, Black Woodpecker, Tree Pipit, Pied Flycatcher. The number of 9 species did not change during the period of the study. 29 species demonstrate decrease of the number and 32 - increase. The main reasons of the number changes were divided into 5 groups: 1) changes in geographical scales or the expansion (peculiar for 3 species), 2) synurbization (29 species), 3) general population changes (38 species) і 4) local environmental changes (45 species), 5) unknown reasons (7). Several reasons worked together for 33 species.

The Effect of Pine Forest Structure on Bird-Mobbing Behavior: From Individual Response to Community Composition

Pine-forest bird communities are affected by the forest structure and the density and composition of its understory vegetation. In this study, we focused on the combined effects of vegetation structure and caller identity on the mobbing behavior of birds in breeding and non-breeding seasons. We examined the effect of the understory structure and the density of three types of conifer forest habitats on bird behavior by broadcasting three different types of mobbing calls: Those of two all-year resident species in the state Israel (Sardinian warbler Sylvia melanocephala Gmelin and great tit Parus major L.) and one European species (coal tit Periparus ater L.), which is absent from these habitats. The mobbing call attracted 689 birds of 17 species, which represented 31% to 95% of the forest bird species that we detected in point counts at the same study plots. Bird reactions to mobbing calls were affected by the status and season, depending on forest type. Our results show that responses were stronger in forests with developed understory in comparison to forests with no understory, especially in winter. The highest number of responders and highest species richness of responders were observed in winter. P. major calls generated more interspecific than intraspecific responses, whereas S. melanocephala calls generated equal levels of inter- and intraspecific reactions. Both species generated different response patterns across the three forest habitat types. The response level of responders is higher when the mobbing calls are issued by local species rather than the P. ater. In winter, the response of non-resident species was higher than of resident species. Based on these results, we encourage the managers to maintain well-established understory vegetation, with special attention to the shrubs layer, to promote species diversity and rich behavioral responses of birds in the conifer forests in the eastern Mediterranean region.

Stepping stones

Purpose Large-scale urbanisation has become a significant barrier to the natural migration of tree species, which is being exacerbated by accelerated climate change. Within this context, improving the permeability of urban landscapes is expected to be an effective strategy to facilitate the process of forest migration through cities. The purpose of this paper is to develop a method to assess the permeability of urban green spaces as stepping stones for forest migration, from the perspective of seed dispersal. Design/methodology/approach The proposed method combines a least-cost path (LCP) model and a graph theory-based approach. The LCP model is applied to map the potential pathways of seed dispersal at multiple spatial and temporal scales, based on which graph theory-based indices are used to quantify the accessibility of urban landscapes for seed dispersers. This method is demonstrated by a case study in the Greater Manchester area, UK. Eurasian jay, Eurasian siskin, coal tit and grey squirrel are selected as the main seed dispersers in the study area. Findings The results provide a comparison of the landscape permeability maps generated from different seed dispersers and identify key areas likely to facilitate the process of forest migration. Recommendations regarding landscape management for improving permeability are also discussed. Originality/value This method allows designers to re-visualise highly modified and fragmented urban landscapes as stepping stones for seed dispersal, which in turn allows for a more piecemeal form of landscape design to optimise urban landscapes for climate adaptation.

Using nest-boxes in pine stands of the Augustów Forest

In 2011–2014, the occupancy of nest-boxes by secondary hole-nesting birds and their breeding success was investigated in pine stands of the Augustów Forest (North-Eastern Poland). In the studied area of 12600 ha, the share of Scots Pine Pinus sylvestris L. in the stands was 92%. On average, birds occupied 54% and bats 3% of the 224–317 nest boxes controlled yearly. Nest boxes were also used by the Pygmy Owl Glaucidium passerinum L. as food caches. In total, broods of nine secondary hole-nesting species were observed, but only four bird species nested in each year of study. The most numerous species, occupying 53–60% of all boxes each year was the Pied Flycatcher Ficedula hypoleuca Pall. The Great Tit Parus major L. occupied 15–24% and the Coal Tit Periparus ater L. 10–12% of available nest-boxes, while the Redstart Phoenicurus phoenicurus L. used 2–7% of nest boxes. The yearly breeding success was highest for tits (Great Tit – 52–84%, Coal Tit – 50–72%) and strongly variable for the Pied Flycatchers – 38–78%. Broods were lost due to predation by martens Martes sp. (38%) and great spotted woodpeckers Dendrocopos major L. (6%) as well as nest competition (2%). The nest-boxes were occupied at a constant rate during the following four years after their exposition. Over 67% of the new nest-boxes were occupied annually which means new nest-boxes (up to 4 years) were occupied significantly more often than boxes older than 4 years.

Peripherally injected ghrelin and leptin reduce food hoarding and mass gain in the coal tit ( Periparus ater )

In birds little is known about the hormonal signals that communicate nutritional state to the brain and regulate appetitive behaviours. In mammals, the peptide hormones ghrelin and leptin elevate and inhibit consumption and food hoarding, respectively. But in birds, administration of both ghrelin and leptin inhibit food consumption. The role of these hormones in the regulation of food hoarding in avian species has not been examined. To investigate this, we injected wild caught coal tits ( Periparus ater ) with leptin, high-dose ghrelin, low-dose ghrelin and a saline control in the laboratory. We then measured food hoarding and mass gain, as a proxy of food consumption, every 20 min for 2 h post-injection. Both high-dose ghrelin and leptin injections significantly reduced hoarding and mass gain compared with controls. Our results provide the first evidence that hoarding behaviour can be reduced by both leptin and ghrelin in a wild bird. These findings add to evidence that the hormonal control of food consumption and hoarding in avian species differs from that in mammals. Food hoarding and consumptive behaviours consistently show the same response to peripheral signals of nutritional state, suggesting that the hormonal regulation of food hoarding has evolved from the consumption regulatory system.