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The feeding of sexually mature European perch (Perca fluviatilis L.) in Lake Kortowskie in the autumn-winter period

100%

Wziatek B. , Poczyczynski P. , Kozlowski J. , Wojnar K.

Archives of Polish Fisheries

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2004

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tom 12

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nr 2

EN

This study addressed the feeding of sexually mature perch (Perca fluviatilis L.) in Lake Kortowskie in the autumn-winter period (October-March). A total of 81 perch specimens were caught, of which 20.2% were males, 69.1% females, and 7 specimens were of unidentified sex. The composition of the perch diet was very diversified. The food contained zooplankton, insect larvae, fish, and other components. Zooplankton was the most significant in late autumn (54.9% frequency of occurrence), whereas fish and insect larvae were found to dominate in winter. Differences in feeding were observed between the sexes (there was a lack of fish in the male diet) and between specimens of different length classes (specimens with lengths over 20 cm were obligatory predators).

PL

Przeprowadzono badania dotyczące odżywiania się dojrzałego płciowo okonia (Perca fluviatilis L.) w okresie jesienno-zimowym (październik - marzec) w Jeziorze Kortowskim. Ogółem odłowiono 81 sztuk ryb, z czego samce stanowiły 20,2%, a samice 69,1%; u siedmiu osobników płci nie udało się ustalić (tab. 1). Skład pokarmu okonia był bardzo zróżnicowany. Występował w nim: zooplankton, larwy owadów i ryby. Największy udział zooplanktonu zanotowano późną jesienią (54,9% częstości występowania), natomiast ryby i larwy owadów dominowały zimą (tab. 2). Stwierdzono występowanie różnic w odżywianiu się zarówno w odniesieniu do płci (brak ryb w diecie samców), jak też klas długości (osobniki powyżej 20 cm były obligatoryjnymi drapieżnikami) (tab. 3).

2

Hunting habitat preferences of raptors in a mountainous area [Northwestern Spain]

84%

Tapia L. , Dominguez J. , Rodriguez L.

Polish Journal of Ecology

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2008

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tom 56

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nr 2

323-333

EN

The hunting habitat preferences of six diurnal raptors (see below) were studied during spring-summer and autumn-winter periods in a mountainous area of northwestern Spain (the Baixa Limia-Serra do Xurés Natural Park). For this, 15 counting-points were established (at 800 m a.s.l.) in the study area between February 1997 and January 1998. Each point was sampled 4 hours per month. The dependent variables used were presence-absence and specific relative abundance (number of birds hr⁻¹km⁻²). Seventeen environmental variables (number of settlements, surface area occupied by settlements, road length, minimum altitude, maximum altitude, max-min altitude, mean altitude, min slope, max slope, max-min slope, mean slope, surface area occupied by scrub-pasture, surface area occupied by forest, scrub-forest edge, number of people hr⁻¹ km⁻², livestock hr⁻¹ km⁻², vehicles hr⁻¹ km⁻²) were used as predictors for characterizing the hunting habitat patterns between March and August (spring-summer period) and between September and February (autumn-winter period). Information regarding each independent variable in the monitoring areas was obtained from 1:50000 digital maps. We analysed the habitat selection patterns of six raptor species, using univariate and multivariate analysis. The PCA generated three factors that accounted for 84% of the variance in spring-summer and 81% of the variance in autumn-winter. The Short-toed Eagle Circaetus gallicus (Gmelin) did not show any pattern in their habitat selection. The Hen Harrier Circus cyaneus (L.) and Montagu´s Harrier Circus pygargus (L.) were more often observed in higher, more gently sloping areas. The spring-summer abundance of the Common Buzzard Buteo buteo (L.) was positively correlated with the surface area occupied by human settlements and the surface area occupied by forest, and in the autumn-winter period its abundance was negatively correlated with the mean slope. The Golden Eagle Aquila chrysaetos (L.) showed similar hunting habitat selection patterns in both periods, with a preference for shrub areas and weak presence of human settlements. The Common Kestrel Falco tinnunculus (L.) did not show any pattern of habitat selection in the spring-summer period but its abundance was negatively correlated with the mean slope in the autumn-winter period.

3

Ochrona i pielęgnacja betonu w warunkach obniżonej temperatury

84%

Owczarska K.

Inżynier Budownictwa

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2024

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tom nr 2

52--56

4

Nest construction during autumn display and winter roosting in the Tree Sparrows Passer montanus

67%

Pinowski J. , Pinowska B. , Chernetsov N. , Romanowski J. , Sierakowski K.

Acta Ornithologica

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2008

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tom 43

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nr 2

185-195

EN

A study of Tree Sparrows was conducted near Warsaw, central Poland. During the breeding season, nest boxes were checked to record the presence of Tree Sparrow nests and broods. Nestlings, juveniles, and adults captured in mist nets were ringed with different combinations of colour rings to identify their age during visual observations in the autumn sexual display period. Before the autumn display, breeding nests were dyed in order to identify nest material added during the autumn display period. In winter, nest boxes were inspected to catch the birds roosting in them at night. The study was conducted in optimal and marginal habitat types. In the optimal habitat during the autumn sexual display, adult birds were much more abundant than in the marginal habitat. During the breeding season, 41% of the nest boxes were occupied in the optimal habitat, compared with 8% in the marginal habitat. The respective figures during the autumn display were 95% and 45%. Autumn nests were built in 83% and 12% of the nest boxes, respectively, and in winter, 35% and 7% of nest boxes, respectively, were used by birds for night-time roosting at night. The autumn display continued from early September to the end of October. For roosting at night in winter (November-March), Tree Sparrows selected nests according to their insulating quality. Most often they roosted in nest boxes containing nests from the breeding season with autumn nests built over them, then, in descending order of frequency, in nest boxes with autumn nests built in empty boxes, in boxes with breeding nests, and in completely empty boxes. Among birds roosting at night and captured on the first survey in winter, 86% were represented by pairs that had built those nests during the autumn display. Young birds that did not build autumn nests typically roosted at night in tree crowns. This implies that the construction of autumn nests is primarily a consequence of the autumn sexual display, and secondarily may be an adaptation for winter survival. The winter survival rate was significantly higher in juvenile Tree Sparrows that were found in nest boxes on winter nights than in those that were not.

PL

Mazurki odbywają zaloty jesienne, tworzą pary i budują gniazda jesienne, w których następnie nocują w czasie zimy. Stopień zaawansowania budowy gniazda zależy od terminu utworzenia pary, a ten zależy od wieku ptaków. Bardziej zawansowaną konstrukcję gniazda budują ptaki stare i młode z pierwszego lęgu. W kolonii marginalnej, w której mazurki gnieździły się tylko sporadycznie, zaloty jesienne odbywały prawie wyłącznie ptaki młode zajmując połowę skrzynek, jednak gniazda jesienne zbudowane zostały tylko w kilku skrzynkach. Wskazuje to, że para w okresie zimowym ze zbudowanym w czasie zalotów jesiennych gniazdem związana jest dwojako; jako z miejscem snu i jako z gniazdem z okresu zalotów i dlatego mazurki w kolonii marginalnej, gdzie odbywały zaloty prawie wyłącznie ptaki młode, zbyt późno rozpoczynające zaloty jesienne aby mogły zbudować gniazdo jesienne, nocowały w koronach drzew i krzewach, a prawie nigdy w skrzynkach. W kolonii optymalnej znaczna część ptaków przylatujących na nocleg także nie nocowała w skrzynkach, prawdopodobnie były to ptaki młode. Determinantem nocowania w skrzynce lęgowej jest utworzenie pary i zbudowanie gniazda jesiennego. Dobór naturalny faworyzuje ptaki stare i młode z wczesnych lęgów, które wcześnie przystępują do zalotów jesiennych i budują gniazda jesienne zapewniające lepsze schronienie w okresie zimy, w porównaniu z ptakami młodymi z późniejszych lęgów, które nie budują gniazd jesiennych i nie nocują w skrzynkach.