Wyniki wyszukiwania

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Feeding effort of male Tawny Owls Strix aluco follows a fixed schedule: a field experiment in the early nestling period

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Sasvari L., Hegyi Z.

Acta Ornithologica

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2010

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tom 45

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nr 2

2

Small mammals in the diet of the Tawny Owl [Strix aluco L.] in Central European Lowland

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Zmihorski M., Balciauskiene L., Romanowski J.

Polish Journal of Ecology

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2008

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tom 56

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nr 4

693-700

We analysed the variation of small mammal species composition in the Tawny Owl Strix aluco L. diet in forest habitats of Central European Lowland. We used published and unpublished materials from forest-dominated landscapes in Lithuania (n = 7 locations), Poland (n = 8) and East Germany (n = 1); marginal localities were ca. 870 km from each other. We recorded that in Central European Lowland the proportion of Arvicolidae in the Tawny Owl diet significantly increased, while that of Muridae decreased toward north-east. The proportion of less common rodent species (including Gliridae and Sicita betulina Pallas) in the diet also increased significantly toward NE. We did not record any trend of small mammals diversity along the analysed transect. We suggest that the change of Arvicolidae to Muridae ratio toward north-east can be caused by the replacement of mice with boreal vole species in small mammal community. Small mammal diversity in Central Europe is subject of discussion.

3

Influence of habitat urbanisation on time of breeding and productivity of Tawny Owl (Strix aluco)

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Gryz J., Krauze-Gryz D.

Polish Journal of Ecology

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2018

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tom 66

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nr 2

An increasing urbanization of habitats in which birds live influences their populations by modifying behaviour, dietary composition, causes of mortality and variables related to breeding. This study aimed to compare breeding periods and productivity among tawny owls, Strix aluco, inhabiting either an urban or an extra-urban area. Studies were conducted in parallel in two locations: central zone of Warsaw – the Polish capital – and the Rogów Forest – ca 70 km west of Warsaw. Number of fledglings and the beginning of the breeding period was assessed by direct observations and listening to calls of juveniles within tawny owl territories. Birds in the urban area were found to start breeding significantly earlier (from 5th February) than those in the extra-urban area (from 17th March). However, the two populations proved to be similarly productive, with 3.2 or 3.4 young per nest on average. The phenomenon of early breeding in city dwelling birds was confirmed in other tawny owl populations as well as other bird species. It can be potentially driven by factors such as higher temperature, artificial light and rich and stable food base.

4

The role of forest age, habitat quality, food resources and weather conditions for Tawny Owl Strix aluco populations

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Wiacek J., Polak M., Grzywaczewski G.

Polish Journal of Environmental Studies

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2010

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tom 19

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nr 5

The main goal of this study was to determine the reason for the significant increase of the tawny owl Strix aluco population in Kozłówka Forest near Lubartów (51°30' N, 22°35' E) in eastern Poland. Since 1990, this forest complex has been part of Kozłowiecki Landscape Park. Our research was conducted using standard playback method on a sample plot covering 50 km2. Each year in March and April 1990-91 and 2007-09, three counts with vocal stimulation were performed on the study plot. Between 1991 and 2009, a significant increase in the density of the tawny owl population was observed from 2.4 pairs/10 km2 to 4.6 pairs/10 km2. We discuss how habitat quality, food availability, and weather conditions can explain this phenomenon.

5

Plasma testosterone profile of male Tawny Owls Strix aluco in relation to breeding density, breeding experience, and offspring provision

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Sasvari L., Peczely P., Hegyi Z.

Acta Ornithologica

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2009

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tom 44

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nr 1

The role of plasma testosterone in territorial behavior and breeding success, which has not previously been examined in nocturnal raptors, was studied in male Tawny Owls. Blood was collected for testosterone analysis during the territorial and nestling periods from owls breeding in nest boxes in Duna-Ipoly National Park, Hungary. Testosterone levels, defense activity, prey supply for broods and reproductive performance were related to breeding density and breeding experience of males. Defense activity, as measured by responses to broadcasted hooting calls and dummy owls during the territorial period, correlated positively with testosterone concentration. Males with more breeding experience had high testosterone levels and occupied better territories in dense breeding areas than less experienced males which had low testosterone concentrations. Mate fidelity was linked male quality: females were more likely to be tenacious in good territories. Testosterone levels dropped between territorial and feeding periods, however males with higher concentrations fed nestlings more frequently with high mass prey per night because food was more abundant in territories they had secured. We suggest that differences in testosterone levels in the provisioning period are related to the males' abilities to acquire territories of different quality.

6

Changes in density and territory size of the Tawny Owl Strix aluco along an altitude gradient: the effect of forest types and wood cover

100%

Salvati L., Ranazzi L.

Acta Zoologica Cracoviensia

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2002

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tom 45

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nr 2

The authors correlated the percentage cover of forested areas with Tawny Owl Strix aluco density and territory size measured in deciduous woodlands along the elevation gradient in central Italy. They calculated the amount of wooded areas per owl territory on the basis of four forest types (urban woods, sclerophyllous woods, mesophilous woods, and montane beech woods). Breeding density differed 3-fold among forest types and suggests that wood quality has a direct effect in determining spatial patterns. The amount of wooded areas per territory is fairly stable in all forest types, and indicates a mean requirement of ca. 10 ha per territory. The smallest territories were in ca. 5 ha sized. Minimum habitat requirement may depend locally on wood quality. Management strategies based on the forest type should be undertaken to protect the local high-density populations of this owl.

7

Long-term stability of tawny owl (Strix aluco) population despite varying environmental conditions – a case study from Central Poland

80%

Gryz J., Chojnacka-Ozga L., Krauze-Gryz D.

Polish Journal of Ecology

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2019

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tom 67

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nr 1

Our aim was to determine dynamics in a population of tawny owls Strix aluco over 15-year period, in relation to year-to-year variation in environmental conditions. The research was carried out in a habitat mosaic of fields and forest in central Poland, over the 2004–2018 period. Numbers of pairs (territories) were established by the standard playback survey technique supplemented by searches for nest sites. The selected environmental factors studied in parallel were the acorn production, density changes in field and forest rodents, meteorological conditions in winter and density of martens (Martes spp.). At the start of the study period 20 nest boxes designed for tawny owls were placed out in the study area. This number was enlarged by additional 27 nest boxes placed in 2012. The number of owls in the area remained stable – in the range of 26–29 pairs, despite changes in nesting sites availability. However, moderate influence of rodent density and winter conditions on population abundance was detected. Also, peak in the rodent population coincided with greater clutch size and numbers of young owls reared. Densities of martens remained relatively stable throughout the study period, and there were no reported cases of these carnivores killing tawny owls, despite the former taking shelter in the owl-boxes.

8

Localities of three rare mammal species in central and northeastern Poland

80%

Lesinski G., Gryz J.

Fragmenta Faunistica

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2008

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tom 51

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nr 1

Analyses of 69 collections of the tawny owls' pellets (28 containing over 100 prey items) revealed the presence of three rare mammal species on several localities in central and northeastern Poland: Muscardinus avellanarius (11 localities), Sicista betulina (3), and Crocidura leucodon (2). The obtained results supplemented data on their distribution close to the borders of continuous ranges. The Kampinos Forest was confirmed as important refuge of M avellanarius, and the lower basin of the Biebrza Valley for both M. avellanarius and S. betulina.

9

Breeding performance, apparent survival, nesting location and diet in a local population of the Tawny Owl Strix aluco in Central Lithuania over the long-term

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Grasyte G., Rumbutis S., Dagys M., Treinys R.

Acta Ornithologica

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2016

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tom 51

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nr 2

In the present study, we used 37-year long dataset on Tawny Owls from the annual monitoring of nestboxes at a sample plot in Central Lithuania. We expected that Tawny Owls responded to changes in land use practices, stemming from a change in both political and economic system, which may affect prey abundance and composition, breeding performance and demography. To analyze temporal changes in monitored parameters, we divided the study period into three phases (1978-1989,1990-2001 and 2002-2014), corresponding to different socio-economic conditions. The number of nesting pairs of Tawny Owls decreased significantly in the last 13 years of the study, but the number of successful pairs fluctuated without any trend. The clutch size and number of nestlings varied without significant trends, but nesting success improved over the last 13 years. Annual apparent survival probability of the female Tawny Owls did not vary significantly over the study period (model averaged values between 0.71 and 0.73). Owls occupied nestboxes irrespective to the distance from the agricultural land during the first two study periods, but since early 2000s, owls tended to occupy nestboxes located deeper in the forest. Birds and small mammals were similarly important as prey items by biomass. Since the 1990s, the share of Microtus voles significantly decreased in the diet, while that of birds increased. In summary, changes in the diet, improved nesting success of the Tawny Owl and tendency of nesting in forest interior may indicate ongoing complex responses to the changes in environmental conditions.

10

Small mammals of Kampinos National Park and its protection zone, as revealed by analyses of the diet of tawny owls Strix aluco Linnaeus, 1758

80%

Lesinski G., Romanowski J., Gryz J., Olszewski A., Kowalski M., Krauze-Gryz D., Olech B., Peplowska-Marczak D., Tarlowski A.

Fragmenta Faunistica

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2013

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tom 56

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nr 1

Analyses of tawny owl pellets were used to determine the species composition and distribution of small mammals in Kampinos National Park and its protection zone (central Poland). The total material collected from 58 localities contained the remains of 11,235 vertebrates (including 8,335 mammals). The study revealed 29 species of small mammals of the following orders: Soricomorpha - 4, Chiroptera - 9, Rodentia - 14, Lagomorpha - 1 and Carnivora - 1. These included two bat species of special interest (Myotis myotis and Barbastella barbastellus) listed in the 2nd Annex to the Habitats Directive of the European Union. Muscardinus avellanarius, a rodent typical of broad-leaved woodland, appeared to be relatively common and abundant in suitable habitats. Species inhabiting wet habitats, Microtus oeconomus and Neomys fodiens, were found in many localities, whereas Arvicola amphibius was rarer and less abundant. Some important refuges of small mammals were found, mostly in strictly protected areas. Although the studies conducted to date in this area likely reveal a complete list of small species of Soricomorpha and Rodentia, it is possible that 3-5 species of Chiroptera and 2 small species of Carnivora may remain to be identified.

11

Notes on the diet successful and failed breeding Tawny Owls [Strix aluco] in urban Rome, Italy

80%

Ranazzi L., Manganaro A., Salvati L.

Acta Zoologica Cracoviensia

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2001

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tom 44

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nr 1

12

Patterns of bird bone fragmentation in pellets of the Tawny Owl [Strix aluco] and the Eagle Owl [Bubo bubo] and their taphonomic implications

80%

Bochenski Z., Tomek T., Boev Z., Mitev I.

Acta Zoologica Cracoviensia

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1993

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tom 36

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nr 2

13

Monitoring of Owls in Latvia

70%

Avotins A., Kemlers A.

The Ring

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1993

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tom 15

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nr 1-2

14

Skrzynki lęgowe puszczyków (Strix aluco L.) jako środowisko występowania niektórych gatunków motyli (Lepidoptera)

61%

Jaworski T., Gryz J., Krauze-Gryz D.

Wiadomości Entomologiczne

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2012

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tom 31

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nr 1

Data on the occurrence of some Lepidoptera species inhabiting nest boxes of the tawny owl (Strix aluco L.) are given.

15

Seasonal movements of Owls [Strigiformes] in the Baltic Region based on ringing data

51%

Dobrynina I. N.

The Ring

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1994

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tom 16

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nr 1-2

Ograniczanie wyników

Feeding effort of male Tawny Owls Strix aluco follows a fixed schedule: a field experiment in the early nestling period

Small mammals in the diet of the Tawny Owl [Strix aluco L.] in Central European Lowland

Influence of habitat urbanisation on time of breeding and productivity of Tawny Owl (Strix aluco)

The role of forest age, habitat quality, food resources and weather conditions for Tawny Owl Strix aluco populations

Plasma testosterone profile of male Tawny Owls Strix aluco in relation to breeding density, breeding experience, and offspring provision

Changes in density and territory size of the Tawny Owl Strix aluco along an altitude gradient: the effect of forest types and wood cover

Long-term stability of tawny owl (Strix aluco) population despite varying environmental conditions – a case study from Central Poland

Localities of three rare mammal species in central and northeastern Poland

Breeding performance, apparent survival, nesting location and diet in a local population of the Tawny Owl Strix aluco in Central Lithuania over the long-term

Small mammals of Kampinos National Park and its protection zone, as revealed by analyses of the diet of tawny owls Strix aluco Linnaeus, 1758

Notes on the diet successful and failed breeding Tawny Owls [Strix aluco] in urban Rome, Italy

Patterns of bird bone fragmentation in pellets of the Tawny Owl [Strix aluco] and the Eagle Owl [Bubo bubo] and their taphonomic implications

Monitoring of Owls in Latvia

Skrzynki lęgowe puszczyków (Strix aluco L.) jako środowisko występowania niektórych gatunków motyli (Lepidoptera)

Seasonal movements of Owls [Strigiformes] in the Baltic Region based on ringing data