Additions to the list of bird species in the Shushensky Bor National Park

This work includes additions to the existing annotated list of birds of the Shushensky Bor National Park, given in the book by ornithologist S.Yu. Petrov and senior state inspector S.V. Chumakov Birds of the Shushensky Bor National Park, published in 2020 in an electronic form. The paper provides general data on the avifauna of the national park, as well as the results of recent studies as of early 2021. The paper provides information on the sightings of 11 bird species that were not previously recorded in the park as a whole: Ptyonoprogne rupestris (Scopoli, 1769); Turdus merula (Linnaeus, 1758); Monticola saxatilis (Linnaeus, 1766); Ficedula hypoleuca (Pallas, 1764) аnd on individual cluster sites Mountain forestry: Podiceps cristatus (Linnaeus, 1758); Crex crex (Linnaeus, 1758); Charadrius dubius (Scopoli, 1786); Turdus obscurus J.F. Gmelin, 1789; Turdus iliacus (Linnaeus, 1766) and Perovsky forestry: Lanius borealis [excubitor] (Vieillot, 1807); Chloris chloris (Linnaeus, 1758), indicating the nature of their stay and biotopic distribution. The paper is illustrated with photographs taken on the territory of both clusters of the national park by employees of the Shushensky Bor National Park and by local birdwatchers.

Abundances and breeding phenology of three sympatric grebes (little grebe Tachybaptus ruficollis, great crested grebe Podiceps cristatus and black-necked grebe Podiceps nigricollis) in Dayet El Ferd, Algeria

In this current study, we examine the abundances and breeding phenology of three sympatric grebes (little, great crested and black-necked grebes) in Dayet El Ferd. These grebes were observed during all the period (2011-2018) in this wetland, except in September when the great crested grebe leaves the region. The abundances of these three grebes show a significant difference. In 2017, the total number of 71 nests was measured. The mean clutch size was 5.23 ± 1.49 eggs per nest. The highest number of eggs per nest was ten eggs, and most nests contained three eggs (N=18).

Comparison of spring and summer clutches of Great Crested Grebes (Podiceps cristatus)

The intensively farmed fishponds of the Třeboň Basin in South Bohemia, Czech Republic host a substantial number Great Crested Grebe (Podiceps cristatus) pairs that nest later than the expected spring season and instead in summer, which may be associated with fishpond farming. A two-factor nested ANOVA of Great Crested Grebe egg and clutch characteristics showed no differences between spring (May-June) and summer (July - August) seasonal clutches. High egg total volume in spring nests was significantly related to both decreasing distance between nests and decreasing number of nests on the fishpond. The increase of total egg volume in summer nests was significantly related to the distance to the edge of littoral vegetation. There is no substantial difference between spring and summer egg characteristics, but total egg volume in spring nests is dependent on other characteristics that those in summer nests.

Estimation of native and alkylated polycyclic aromatic hydrocarbons (PAHs) in seabirds from the south coast of the Baltic Sea

Native and alkylated polycyclic aromatic hydrocarbons (PAHs) were examined in the muscle, liver, kidneys, and lungs of greater scaup (Aythya marila) and great crested grebe (Podiceps cristatus). Both species showed differences in distribution and profiles among the tissues. The highest ƩPAH concentrations were in the scaup lungs and the grebe kidneys (20 and 19 ng g−1 wet weight, respectively). Alkylated derivatives were in the range of 61 to 77% of ΣPAHs in both species. Differences in PAH profiles between birds, analyzed by PCA, were probably results of metabolic capability, not various diet. In comparison to available data from other regions of the world, PAH levels in investigated species are relatively low and do not pose a threat to birds themselves.

Breeding population increase and range expansion of the Great Crested Grebe Podiceps cristatus in southeastern Norway

The Great Crested Grebe Podiceps cristatus is listed as near-threatened on the Norwegian red list due to small population size, estimated in 2015 at 220–380 pairs. Population size is considered to be stable. Approximately one quarter of the population (50–100 pairs) is thought to occur in Oslo and Akershus, but this estimate is not based on detailed data, and the only previous systematic estimate was 90–100 pairs in 13 sites in 1982. In 2018, I conducted a comprehensive survey of all known and potential breeding sites to assess current population size in Oslo and Akershus. I recorded 233 pairs in 34 sites, suggesting a large increase in population size. To analyse the population increase in more detail, I collected all known records of Great Crested Grebes during the breeding season for the period 1995–2018. Analyses confirmed that there has been a strong increase, at a yearly rate of 4.2%. The increase was both due to increases in already established populations (69% of total increase), and establishment of new sites (31%). New sites were colonised in particular the last 10–15 years, and new sites were located gradually further away from the sites that were already used in 1982, indicating continuous range expansion. New sites were also located in smaller, less nutrient-rich lakes at higher elevations, perhaps indicating occupation of lower quality sites that could limit further population increase. Similar population increases have also occurred in other parts of the distribution range of Great Crested Grebes in Norway, and I present a new population size estimate for Norway at 531–634 pairs. Hence, the species no longer qualifies for red listing, and one may consider to downlist the species to least concern.