Issue 2021-1

Ornis Polonica 2021, 62: 1–16

Diet of the Golden Eagle Aquila chrysaetos in the Polish part of the Carpathians in 2000–2019

Marian Stój, Robert Kruszyk

Abstract: The remains of prey and pellets from the nests of the Golden Eagle were collected in the Polish part of the Carpathians between 2000 and 2019. In total, 601 prey remains were collected, including 285 mammalian (47.3% of the prey amount), 309 avian (51.5%), and 7 reptilian (1.2%) items. We were able to identify 19 species of mammals, 22 species of birds and 2 species of reptiles among prey items. In terms of biomass, mammals dominated making up 68.4% of all items. Birds and reptiles constituted 31.4%, and 0.2% of the total food biomass, respectively. The average mass of the prey calculated for all identified prey was 961 g. The average mass of the avian and mammalian prey was 623 g and 1340 g, respectively. Medium-sized mammals, such as Roe Deer Capreolus capreolus, martens Martes sp., Fox Vulpes vulpes, Hare Lepus europaeus and cats Felis sp., as well as medium and larger birds (owls, pigeons, birds of prey, corvids, grouse and domestic fowl) constituted the main prey of the Golden Eagle in the Polish part of the Carpathians. Compared to the data from the 1990s, the number of Roe deer, owls, birds of prey and pigeons in the Golden Eagle diet increased significantly, while the number of hares and crows decreased. Chicks and fledglings, mainly Common Buzzard Buteo buteo, and owls – Strix aluco and S. uralensis made up at least 7% of all avian prey. Among the owls, chicks accounted for 16.7% of the prey items. The width of the food niche (8.7) reported in this study is similar to the values reported for the Polish Carpathians in the 1990s and greater than found in other regions of Europe. The presence of typical forest animals in food, e.g. owls, bird chicks, dormice Glis glis, squirrels Sciurus vulgaris or martens, indicates that the Golden Eagle regularly hunts not only in open spaces but also in the forest.

Key words: Golden Eagle, Aquila chrysaetos, diet, mountains, mammals and birds, forest

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Ornis Polonica 2021, 62: 17–29

The effect of active nest protection on the productivity of the Montagu’s Harrier Circus pygargus

Tomasz Przybyliński, Krzysztof Myśliwiec

Abstract: In 2017–2020 the monitoring and active protection of a breeding population of the Montagu’s Harrier Circus pygargus were carried out in Kutno district (central Poland). We aimed to estimate the species number and describe its nesting habitats. Furthermore, we aimed to implement an active protection of nests to prevent the damage of broods during agrotechnical works in the fields. A total of 144 cases of confirmed or probable breeding records were noted. Breeding habitats were described for 112 broods, and they included winter triticale (40.2%), weat (26.8%) and rape (27.7%). We found significant differences between years in the frequency of birds nesting in different crops. Low spring temperatures observed in some years delayed grain growth. As a result more birds laid their clutches among faster growing rape. A total of 75 of 133 clutches (56.4%) was successful. Mean production of fledged young per a breeding pair was 1.59, but there were important differences between years (from 0.71 young/pair in 2017 to 2.0 young/pair in 2019). Of 75 nests 47 were classified as endangered by fieldworks, and hence they were surrounded by a net. The net protected nestlings against terrestrial predators and prevented collisions with agricultural equipment. A total of 91.5% of protected nests were successful (produced at least one fledgling) while the corresponding value for the remaining nests was 78.6% (N = 28). The productivity of pairs whose nests were protected was significantly higher (2.87 young/pair) than that of unprotected nests (1.96 young/pair). These differences may have resulted from the absence of failures caused by mammals in protected nests. Therefore, we can conclude that 39.9% of all fledged young left the nests as a result of protective measures. Nest protection doubled the productivity of breeding pairs in three of four breeding seasons. Productivity of 1.5 young/pair, reached in 2018–2020, should allow to maintain the stable population of Montagu’s Harrier in the area.

Key words: Montagu’s Harrier, Circus pygargus, breeding habitats, active nest protection, productivity

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Ornis Polonica 2021, 62: 30–48

The first record of the Savannah Sparrow Passerculus sandwichensis in Poland and the occurrence of Nearctic passerines in the Western Palearctic

Abstract: The Savannah Sparrow Passerculus sandwichensis from subspecies labradorius / savanna was recorded in the dune area of Jastarnia in the Hel Penninsula (N Poland, the Baltic coast) on 26 June 2020. It was the first record of this Nearctic species in Poland (observation accepted by the Avifaunistic Commission) and the sixth in the Western Palearctic. Nearctic passerines occur regularly in the Western Palearctic, most frequently in the Atlantic islands, less often in the coastal Atlantic areas and exceptionally inland. In 1800–2019 a total of 1736 records of 76 species of Nearctic passerines were reported from the Western Palearctic. In total, representatives of 14 families have been recorded in the Western Palearctic, including the most numerous species Parulidae, Passerellidae, Turdidae, Tyrannidae and Cardinalidae. The Red-eyed Vireo Vireo olivaceus, Buff-bellied Pipit Anthus rubescens, Grey-cheeked Thrush Catharus minimus, Swainson’s Thrush Catharus ustulatus and Blackpoll Warbler Setophaga striata were the most frequently observed species. In 1801–1950, Nearctic passerines were found 46 times in the Western Palearctic. Until the mid-1960s, the number of records had been relatively low and then a gradual increase in the observation numbers was noted. In the last two decades the number of observations fluctuated from 11 to 107 per year. The majority of records (82%) was noted in autumn, mainly in October. Observations in spring (9%, mainly in May), in winter (5%), and summer (4%) were less frequent. Only in Passerellidae family, the spring observations were more frequent compared to autumn ones.

Key words: Savannah Sparrow, Passerculus sandwichensis, Nearctic passerines, phenology, frequency of records, Western Palearctic

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Ornis Polonica 2021, 62: 49–59

Abundance and distribution of the Hazel Grouse Tetrastes bonasia in the Tatra National Park

Marcin Matysek, Robert Gwiazda, Bogusław Binkiewicz, Grzegorz Szewczyk

Abstract: The paper summarizes the results of an inventory of the Hazel Grouse inhabiting the Tatra National Park carried out in 2010–2013. The Hazel Grouse occurrence was detected based on the birds response to the territorial voice of a this species played from an electronic device at points determined systematically every 200 m. In total, 79 sites of this species were recorded and total population size was estimated at approximately 96–104 sites. Density of this species was 0.6 sites/km2 (0.73–0.79 sites/km2 for the estimated population size). The Hazel Grouse was the most numerous in the lower montane zone (48 sites), with density of 0.56 sites/km2. 29 sites were found in the upper montane zone, and density was 0.64 sites/km2. This species inhabited forests and partially the dwarf mountain pine zone where it was not inventoried. It was the most numerous in the altitude range from 1100 to 1300 m above sea level (62% of the inventoried sites). It inhabited mostly the south-west and south-eastern slopes, avoiding the north and north-west ones. The most numerous sites of the Hazel Grouse was in the forests under active protection (34 sites, density of 0.63 sites/km2) in comparison with the forests under strict protection (31 sites, density of 0.58 sites/km2) and landscape protection (14 sites, density of 0.58 sites/km2).

Key words: Hazel Grouse, Tetrastes bonasia, the Tatra Mountains, Tatra National Park, abundance, distribution

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Ornis Polonica 2021, 62: 60–73

Detectability of the Magpie Pica pica during the breeding season in urban habitats – recommendations for the population monitoring

Kamil Kaczmarek

Abstract: In 2017–2020 a breeding population of the Magpie Pica pica was counted in Poznań (W Poland) at housing estates in Rataje district. Within the area of 324.1 ha the number of breeding pairs ranged from 186 to 258. Based on the data from different breeding seasons, an attempt was made to estimate the detectability of the Magpie depending on the seasonal number of visits. My estimates reveal that a single inspection in March–May allows to detect only about 30% of occupied nests. Due to the low detectability of the Magpie, about 75% of nests were classified as occupied on the basis of only one observation of a bird on a nest or in a tree with a nest. For this reason, it is postulated that Magpies should be counted in urban areas 3–4 times during the breeding season (March–May). Other issues related to counting of Magpies in urban habitats are also discussed.

Key words: Magpie, Pica pica, counting methods, detectability

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Ornis Polonica 2021, 62: 74–79

Abundance and distribution of the Boreal Owl Aegolius funereus in the Bydgoszcz Forest in 2020

Rafał Kurowski

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Ornis Polonica 2021, 62: 79–82

The second record of the American Golden Plover Pluvialis dominica in Poland

Zbigniew Kajzer, Sławomir Rubacha

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Ornis Polonica 2021, 62: 83–85

Cofta T. 2020. Flight identification of European passerines and select landbirds. Princeton University Press. ISBN 978-0-691-17757-1

Tadeusz Stawarczyk

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Ornis Polonica 2021, 62: 83–85

Balatski N. 2020. Gniazda ptaków Syberii. Nowosybirsk. ISBN 978-5-93889-384-9

Józef Hordowski

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