Indirect Influence of African Swine Fever Outbreak on the Raven (Corvus corax) Population

Den-Dwelling Carnivores in Central Poland: Long-Term Trends in Abundance and Productivity

The monitoring of medium-sized carnivores is essential because of their role in disease transmission and as predators. We focused on red foxes, badgers, raccoon dogs, and domestic dogs, and considered 9441 ha of field–forest mosaic in Central Poland. We compared current (2011–2018) abundance (i.e., number of natal dens recorded annually) and breeding parameters (assessed with the aid of camera traps) with published past data (1980s–1990s). The red fox population increased after rabies vaccinations were introduced and has increased further in the last few years. The population is now stable, which suggests that other factors, possibly mange, limit the population instead. Contrary to historical data, one-fourth of red fox females now breed outside of forests areas, indicating the high plasticity of the species. The number of natal dens of badgers and recruitment rates have also increased. The mean litter sizes of these two species are positively affected by small rodent availability. The raccoon dog, which is an alien and invasive species, used to be recorded sporadically but now breeds regularly (1.8 breeding cases yearly). Nowadays, free-ranging/feral domestic dogs are not controlled by culling, so they have started to breed in the wild (1.6 cases per year), which is a new occurrence.

Food Niche Overlap of Avian Predators (Falconiformes, Strigiformes) in a Field and Forest Mosaic in Central Poland

Food niche overlap statistics are a common way to show competition for food resources in a group of animals. Niche breadths of various species are very variable and their diet composition changes reflecting prey availability. The aim of this study was to evidence the food niche overlap of the whole assemblage of avian predators (eight raptor and owl species, some of them reaching very high densities) in a field and forest mosaic of central Poland. The diet composition was assessed on the basis of pellet analyses and the identification of prey remains found under the nests in the breeding period. The extent of the niche overlap was calculated using a Pianka formula. The food niche overlap indices ranged from 0.02 to 0.93 (mostly below 0.5). The most separate food niche was that of the white-tailed eagle, who regularly preyed on fish. The highest niche overlap was recorded for the common buzzard and common kestrel, two species preying on field rodents, switching to soricomorphs when the former were scarce. Our results confirmed that the food niches of species coexisting in the same area were considerably separate, which is a result of preying on various prey species or searching for them in different habitats.

African swine fever in wild boar, South Korea, 2019

South Korea is the only Asian country where African swine fever (ASF) is spreading in wild boar (Sus scrofa) populations. This rapid communication describes the situation of ASF in South Korea since its first detection on 17 September 2019 with special attention to ASF dynamics and management in wild boar. Since the first case in a wild boar was detected on 2 October 2019, a total of 86 wild boar have been confirmed as infected by PCR until 18 January 2020, and the monthly number of cases has been growing from October 2019 to January 2020. Interventions to limit ASF spread among wild boar in South Korea consist in fencing, population control and carcass search and disposal. The confirmed ASF-infected sites are immediately fenced, and a three-layer fencing system has been deployed to avoid southward spread of ASF. Hunting and trapping allowed culling 2,623 wild boar on 2,414 km2 (1.08/km2 ), and a total of 889 wild boar carcasses were detected and destroyed. Unfortunately, mine fields impose constraints to effective carcass search, impeding effective quantification of cases and carcass destruction in parts of the infected zone and generating a unique epidemiological setting.

The Common Buzzard Buteo buteo Population in a Changing Environment, Central Poland as a Case Study

Common buzzard is the most abundant bird of prey in Europe, and its population has undergone serious changes. In this study, we focused on a population in Central Poland (study area 105 km2, forests around 24 km2, seven forest complexes) to analyze how certain environmental factors influenced population abundance, breeding parameters, and diet composition. The study was undertaken from 2011 to 2018, and the results were compared with data from two study periods (1982–1992; 2001–2003). Current population density was 3.5 pairs/10 km2 of total area and 14.3 pairs/10 km2 of forested area, it was negatively correlated to the abundance of northern goshawk, and it grew in the last few decades. Mammals were dominant prey (72.6% prey items, 38.6% of biomass), but their share in diet changed following rodent availability. A decrease in the share of voles was recorded, reflecting drop in their abundance and dampening of abundance cycles. Breeding parameters were similar to those in the past, and the number of offspring depended on small rodent availability. Buzzards adapted to changes in the stand structure, i.e., when share of Scots pine decreased, they chose it as their nesting tree less frequently. All this showed that buzzard is a very adaptable species.