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1

Sroka nie jest taka czarno-biała

Nawrot Radosław

Zieleń Miejska

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2019

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Nr 9

34--35

PL

Kto wie, czy głównym powodem masowego osiedlania się srok w miastach nie była ich ogromna inteligencja. Sroki po prostu nie lubią nudy, a w mieście nigdy jej nie ma.

2

Urban and natural components of Korean magpie (Pica pica sericea) territories and their effects on prey density

Kim S., Srygley R., Lee J., Lee S., Choe J.

Polish Journal of Ecology

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2012

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Vol. 60, nr 2

407-417

EN

Urban landscapes have a negative impact on bird species diversity, yet particular species thrive in urban communities. Like many other corvids, the Korean magpie is a successful colonizer of urban environments. On the semiurban campus of Seoul National University in Korea, we investigated whether magpies adjust territory size with building area and secondarily, whether they use vegetation and artificial components of their territory as indicators of prey density. We measured territorial areas and divided these into vegetation and artificial areas, distinguishing building area as a separate feature. We sampled prey density on each territory during the nestling stage. Territory size increased with the square root of building area (SRBA). As the length of building perimeter also increases with SRBA, we conclude that territory size was proportional to building perimeter. Prey density decreased with SRBA indicating that buildings had a negative impact on prey. Breeding success was also negatively related to SRBA. We suggest that magpies adjusted territory size according to the length of building perimeter due to a decline in prey density. As prey density declined, artificial pavement area was added to include open trash bins, which increase the availability of anthropogenic refuse such as discarded food. Vegetation area declined as prey density increased, but changes in vegetation area were minor and had little impact on prey availability measured at ground level. Structural cues were not used to adjust vegetation area, and artificial structural cues were not used to adjust territorial size over direct monitoring of prey density.

3

Parental provisioning in response to natural variation of brood size in the Black-billed magpie (Pica pica L.) : video analysis of behaviors in the nests

Lee S., Jabłoński P., Choe J., Choi J.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

553-562

EN

Natural selection will favor parents who adjust their effort in relation to the fitness costs and benefits from the current brood. In this study, we investigated how magpie parents adjust provisioning effort based on the number of nestlings in the brood, by analyzing video recordings of begging and feeding behaviors of birds. The number of visits per hour increased with brood size, but the number of feeding events per visit did not. Because of the latter, parental provisioning that a nestling is receiving on average decreased in larger broods. This may be viewed either as an evidence for the limitation of parental provisioning in larger broods, or as an evidence of parental strategy optimizing the brood-size-specific provisioning effort for the current reproductive event as a tradeoff between current and future reproduction. With other aspects of parental provisioning behavior, we did not find clear indication that parent confronts upper limitation in provisioning large broods. Pervisit number of feeding and nestlings. body condition around the time of fledging did not depend on brood size, which implies that parental effort is not at its limit in larger broods. Based on the results, we suggest that the provisioning effort of black-billed magpie parents is better explained by the life-history trade-off model for provisioning.

4

The potential role of nests of Black-billed Magpie Pica pica L. in accumulation and dispersal of seeds in agricultural landscape

Czarnecka J., Kitowski I.

Polish Journal of Ecology

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2008

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Vol. 56, nr 4

673-682

EN

The study aimed to describe the seed pool accumulated in the nest material of Magpie Pica pica, and to determine the importance of this mechanism of seed dispersal for such ecological processes as colonization of new habitats and expansion of alien plants. The seedling germination and seed extraction methods were used to determine seed abundance in the soil layer, the inner layer, and in the lining of 9 nests collected in three types of agricultural landscape: the first with domination of arable fields; the second with similar shares of arable fields and other landscape elements such as meadows of different types, shrubs, tree clumps and rushes; and the third with domination of lowland hay meadows. In all the nests, considerable numbers of diaspores were found (from 26 to 371 seeds per nest, belonging to more than 80 taxa). The main plant groups found in the nests are species connected with field roads, weeds and ruderal species, but also meadow and brushwood species were found there. The soil was gathered by birds from habitats with low vegetation cover and large areas of bare soil. Although the structure of seed pool of nests suggests that soil was mainly collected in the close vicinity of the nests. future location, this mechanism of seed dispersal can probably be involved in long distance dispersal. Seeds of two rare kenophytes: Erucastrum gallicum (Willd.) O. E. Schulz and Diplotaxis tenuifolia (L.) DC were found in the material of nests localized more than 100 m away from their closest populations. It can be assumed that this mechanism of seed dispersal can play a potential role in the expansion of alien plants and colonisation of new habitats.

5

Long-term population trends of corvids wintering in urban parks in central Poland

Mazgajski T., Żmihorski M., Halba R., Woźniak A.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

521-526

EN

Changes in the numbers of corvids wintering in Warsaw (Central Poland), in the last sixteen years were analyzed. Four species were studied: Rook Corvus frugilegus L., Jackdaw C. monedula L., Hooded Crow C. corone cornix L. and Magpie Pica pica (L.) The results were based on density data for birds foraging in three urban parks. The bird counts were conducted in November and December 1988.2003. It was found that the number of wintering Rooks decreased significantly (0.5 fold), populations of Jackdaws and Hooded Crows - increased (4.25 and 3.95 fold, respectively), and no apparent trends were observed for Magpies during this period. Observed trends for Rooks as well as comparisons of limited data gathered earlier in other areas may confirm suggestions about the changing of migration routes of this species.