Issue 2023-3

Ornis Polonica 2023, 64: 161–189

Breeding avifauna of the Biebrza River Valley – current numbers and population trends

Łukasz Krajewski, Tomasz Chodkiewicz, Szymon Czernek, Agnieszka Grajewska, Krzysztof Henel, Michał Korniluk, Grzegorz Maciorowski, Piotr Marczakiewicz, Paweł Mirski, Grzegorz Neubauer, Rafał Szczęch, Piotr Świętochowski, Tomasz Tumiel

Abstract: Dozens of publications have been devoted to the breeding avifauna of the Biebrza River Valley, one of the most important bird areas in Poland. However, there is a lack of up-to-date information on the population trends of many species. The paper summarises the results of surveys of selected bird species carried out in 2015–2022. During this period 178 species were confirmed or probable breeders. The area holds more than 80% of the national breeding populations of the Northern Pintail Anas acuta (0–20 females), Greater Spotted Eagle Clanga clanga (10–15 pairs), Short-eared Owl Asio flammeus (0–35 pairs) and Aquatic Warbler Acrocephalus paludicola (3,268–6,621 males) and over 50% of population of the Northern Shoveler Spatula clypeata (490), White-winged Tern Chlidonias leucopterus (0–2,950 pairs), Bluethroat Luscinia svecica (890 males) and Citrine Wagtail Motacilla citreola (60–120 pairs). Local populations of 22 species exceed 5% of the national population size. In the Biebrza River Valley, in the long term, declining trends (26 species) prevail over increasing ones (23 species). In case of most species, the changes in the size of the Biebrza populations reflect the situation of species in the whole Poland or Europe. This indicates the dominant influence of supra-regional phenomena on the avifauna of the Biebrza Valley. Among a few species whose trends do not correspond to changes on a larger spatial scale, the predominance of species whose Biebrza populations exhibit more positive trends than the national populations is evident. The rates of decline of some species is also slower. This suggests that the habitats of the species studied in the Biebrza Valley are in better condition than in other river valleys in Poland, stressing the key importance of this area for the conservation of wetland avifauna.

Key words: waterbirds, wetlands, long-term population trends, the Biebrza River, the Biebrza National Park

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Ornis Polonica 2023, 64: 190–199

Breeding birds communities inhabiting large and small crop areas in the South Podlasie Lowlands

Andrzej Dombrowski

Abstract: The paper presents the abundance and structure of breeding birds communities inhabiting agricultural fields in eastern Poland. Counts were carried out in the South Podlasie Lowland on seven sample plots sown with spring crops: large crop areas, viz. monocultures (5 plots, 134 ha in total) and small crop areas (2 plots with 48 agricultural parcels, 71 ha in total). All plots were surveyed 8 times during the 2007 breeding season using a combined version of the mapping method. The monocultures showed a total of 8 species considered territorial – from 3 to 6 per plot, and the density of breeding bird groups ranged from 2.5 to 5.5 pairs/10 ha (average 3.9 pairs/10 ha). Only three species – the Skylark Alauda arvensis, Yellow Wagtail Motacilla flava and Whitethroat Curruca communis – were present in all controlled plots. The Skylark nested in a wide density gradient of 0.6–1.8 pairs/10 ha and Yellow Wagtail in a narrow range of 1.3–1.6 pairs/10 ha. The Whitethroat showed a strong variation in densities – 0.1–0.6 pairs/10 ha. The Marsh Warbler Acrocephalus palustris, Corncrake Crex crex and Whinchat Saxicola rubetra nested only in rape crops. A total of 12 breeding species were recorded in the two plots of small crop areas. The density of breeding birds was 14.1 and 14.3 pairs/10 ha, respectively. The density of the most numerous species – Skylark – was 9.2 and 9.1 pairs/10 ha, and Yellow Wagtail – 2.2 pairs/10 ha and 1.8 pairs/10 ha, respectively. The species richness of birds inhabiting the small crop areas was higher than in the monocultures, despite the study area being almost twice as small. The total density of breeding birds in small crop areas was more than three times higher than in monocultures. Skylark densities in small crop areas were more than six times higher than in monocultures. Similarly, Whinchat, as well as Quail Coturnix coturnix and Grey Partridge Perdix perdix, were several times more numerous in small crop fields than in monocultures. The Yellow Wagtail was only one-third more numerous in the small-acreage fields, while the Marsh Warbler was more abundant in rape monocultures. The Whitethroat inhabited both habitats in similar densities.

Key words: agricultural landscape, monocultures, breeding birds

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Ornis Polonica 2023, 64: 200–242

Rare Birds Panel in Poland – report of 2021 for non-breeding species

Arkadiusz Sikora, Tomasz Chodkiewicz, Szymon Beuch, Łukasz Ławicki, Robert Cymbała, Paweł Czechowski, Stanisław Czyż, Piotr Dębowski, Andrzej Dylik, Wojciech Guzik, Krzysztof Jankowski, Zbigniew Kajzer, Łukasz Krajewski, Łukasz Matyjasiak, Bartosz Smyk, Marcin Wężyk, Przemysław Wylegała

Abstract: The fourth report of the Rare Bird Panel presents the occurrence of 38 rare species in Poland. This year was very good or the record one for the number of individuals of the Egyptian Goose Alopochen aegyptiaca (598), Black-winged Stilt Himantopus himantopus (121), Purple Sandpiper Calidris maritima (41, including the largest flock of 10 ind.), Purple Heron Ardea purpurea (69), Eurasian Spoonbill Platalea leucorodia (31), Homeyer’s Grey Shrike Lanius excubitor homeyeri (29) and good for the Ruddy Shelduck Tadorna ferruginea (36) and Pallid Harrier Circus macrourus (114). In 2021 very low numbers for the Pomarine Skua Strecorarius pomarinus (7), Glaucous Gull Larus hyperboreus (2), Red-footed Falcon Falco vespertinus (220), Ring-necked Parakeet Psittacula krameri (10), Yellow-browed Warbler Phylloscopus inornatus (8), Greenish Warbler Phylloscopus trochiloides (39) and Ring Ouzel Turdus torquatus outside mountains (15) were recorded. In 2021, the numbers of 12 species were moderate.