Massive Infection of Lungs with Exo-Erythrocytic Meronts in European Robin Erithacus rubecula during Natural Haemoproteus attenuatus Haemoproteosis

Haemoproteus species are widespread avian blood parasites belonging to Haemoproteidae (Haemosporida). Blood stages of these pathogens have been relatively well-investigated, though exo-erythrocytic (tissue) stages remain unidentified for the majority of species. However, recent histopathological studies show that haemoproteins markedly affect bird organs during tissue merogony. This study investigated the exo-erythrocytic development of Haemoproteus (Parahaemoproteus) attenuatus (lineage hROBIN1), the common parasite of flycatchers (Muscicapidae). Naturally infected European robins Erithacus rubecula were examined. Parasite species and lineage were identified using microscopic examination of blood stages and DNA sequence analysis. Parasitaemia intensity varied between 0.8 and 26.5% in seven host individuals. Organs of infected birds were collected and processed for histological examination. Tissues stages (meronts) were seen in six birds and were present only in the lungs. The parasites were usually located in groups and were at different stages of maturation, indicating asynchronous exo-erythrocytic development. In most parasitized individuals, 100 meronts were observed in 1 cm2 section of lungs. The largest meronts reached 108 µm in length. Mature meronts contained numerous roundish merozoites of approximately 0.8 µm in diameter. Megalomeronts were not observed. Massive merogony and resulting damage of lungs is a characteristic feature during H. attenuatus infections and might occur in related parasite lineages, causing haemoproteosis.

Is nesting in closed nestboxes advantageous for the European Robin (Erithacus rubecula)?

Background The European Robin (Erithacus rubecula) is eurytopic in its choice of nest site, which can be either half-open or closed, and situated either on the ground or at a height of several meters. On occasion, robins also nest in closed nestboxes, though generally only solitary such cases are documented, albeit that dozens of such events can be recorded during the course of some long-term studies. However, until now, nobody has summarised the peculiarities of robins nesting in closed nestboxes. Methods In the period 1978–2020, wooden tit and starling nestboxes were inspected regularly at five study sites in Lithuania, this totaling more than 18,000 nestbox-seasons. During these inspections, 90 cases of robins nesting in the nestboxes were recorded. Publications on this topic from the entire robin distribution range were reviewed. Results Robins prefer to nest in old large-sized fairly shallow nestboxes with wide entrance holes, for example starling nestboxes or tit nestboxes with enlarged entrance holes. Increased numbers of nestboxes being occupied by robins were recorded for 3–8 years in row. In Lithuania, nesting success in nestboxes is not higher than compared with nesting on the ground. Tree climbing mammals, Pine Martens (Martes martes), Hazel Dormice (Muscardinus avellanarius), Edible Dormice (Glis glis) and Forest Dormice (Dryomys nitedula), are the main predators of robin nests in nestboxes. Conclusions Some geographic variation was found in the occurrence of robins nesting in nestboxes with more such cases recorded in central and southern parts of the range. Possibly robins are more philopatric in these parts of the range, with the same females or their offspring nesting in nestboxes for several years in row. In areas inhabited by dormice, nesting in closed nestboxes is not advantageous for robins.

Formation of nesting bird communities in parks on the gradient of anthropic load in Kiev metropolis

In settlements, safe places for birds nesting and feeding need to be created. The purpose of the work is to assess the state and identify vectors of the formation of nesting bird communities in parks under the pressure of anthropic load in the metropolis. In parks of Kyiv 62 species of birds nest. Such faunogenetic complexes like European nemoral (25.0–53.3%), Desert-mountain (12.0–27.8%) and Forest-steppe (6.9–25.0%) prevail. The number of community species in each of parks is 49–12, the average nesting density is 0.08±0.02–0.9±0.19 pairs / ha, and the dispersion is 0.12–1.62. With the combination of anthropic load on biotopes of more than 140 points with a small area of parks (2.0–16.5 ha), the species composition of communities decreases, and the average nesting density and density dispersion increase. Dominated by density: Parus major, Columba livia, Sturnus vulgaris, Turdus merula, Passer domesticus, Passer montanus, Fringilla coelebs, Columba palumbus, Apus apus, Ficedula albicollis, Erithacus rubecula, Turdus pilaris. All birds in communities are obligate synanthropes (12.9%; n=62) or hemisinanthropes. Obligate synanthropes are distributed in communities of 0-7 species. According to the gradient of increasing anthropic load on parks, logarithmic trends show a slight increase in the percentage share of obligate synanthropes in the species composition and in the number of breeding pairs. 47–70% nest on trees, 0–14.3% in shrubs, 0–13.0% on ground and in buildings. In parks, birds (16–38% of the species composition), in addition to using species-specific stations, nest in the cavities of buildings. Such species like Motacilla alba L., Sturnus vulgaris, Ficedula albicollis, Muscicapa striata Pallas, Erithacus rubecula, Parus major, Passer domesticus, Passer montanus nest in this way. Due to this nesting strategy, the need of the birds in hollows and the dependence on the woodpeckers in the community decreases. High parameters of the Shannon index (1.51–3.14) and Pielou index (0.61–0.95) were revealed, with low data of the Berger-Parker index (0.15–0.61). With an anthropic load of more than 160 points, there is a sharp decrease in species diversity, evenness of species, and increased dominance pressure. Cluster analysis showed the division of bird communities into similarity groups according to the area of the parks, the proximity of parks to the outskirts of the city and large forest tracts of the area and specifics of the anthropic load.