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2 Polish Journal of Ecology

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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

2012

Vol. 60, nr 2

407-417

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.

Relative abundance and flock size of wintering Common Crossbills Loxia curvirostra L. in Western Carpathians : a habitat influence

Ciach M., Bylicka M.

Polish Journal of Ecology

2009

Vol. 57, nr 1

181-189

A study of wintering Common Crossbills (Loxia curvirostra L.) was conducted in the winter periods 2002/2003-2006/2007 in the Western Carpathians. Birds were surveyed on transects in natural mountain European beech (Fagus sylvatica L.)-Silver fir (Abies alba Mill.)- Norway spruce (Picea abies (L.) Karst.) forests of the Tatra Mts, Pieniny Mts, Babia Góra Mt. and Gorce Mts (total length 41.4 km) as well as in a habitat mosaic with Scots pine (Pinus sylvestris L.) and Mountain pine (Pinus mugo Mill.) stands in the Kotlina Orawsko-Nowotarska valley (total length 31.5 km). Birds mean density underwent annual changes from 1.9 to 15.5 ind. 10 km[^-1] in the natural mountain forests and from 0.9 to 12.1 ind. 10 km[^-1] in the habitat mosaic. The median flock size in the natural mountain forests was 2, and it varied from 1 to 4 in subsequent seasons. They were smaller than flocks recorded in the habitat mosaic in the valley - median 2.5 (from 2 to 7 in subsequent seasons). The size of foraging and flying flocks did not differ significantly in natural mountain forest nor in the valley habitat mosaic. In the natural mountain forests, birds preferred habitats dominated by Norway spruce, and avoided European beech-Silver fir forests. The median flock size was 2 in habitats with Norway spruce, and 8 in stands where Norway spruce was absent. The variation in bird density presumably reflected the changes in quantity and location of food resources. Birds moved within stands with varying proportions of Norway spruce in the mountains as well as between the mountains and the valley, where habitat with mosaics of Scots pine and Mountain pine dominated.