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1

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.

2

Effect of old nest material in nestboxes on ectoparasites abundance and reproductive output in the European Starling (Sturnus vulgaris L.)

Mazgajski T.

Polish Journal of Ecology

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2007

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Vol. 55, nr 2

377-385

EN

Before breeding, hole nesting birds face the problem of the presence of old nest material from previous seasons in their nest sites. This material fills the cavity, making it shallower, resulting in greater brood vulnerability to predators, as well as creating good conditions for ectoparasite development. As a consequence, this may negatively affect many breeding parameters of hole nesters. However, adult birds may compensate the effect of blood sucking ectoparasites by increasing their feeding rates. It is known that the European Starling Sturnus vulgaris L. can deepen its nest site by removing old nest material. Therefore, a study was conducted to find out whether the presence of old nest material influences ectoparasite abundance in newly built nests, reproductive parameters, as well as nestling. body parameters and feeding rates in this species. An experiment with nestboxes was carried out in two forested areas. Two groups of nestboxes were prepared - one contained old nests from the previous breeding season, and the other group was cleaned with old nests removed. During the breeding season, data on Starling reproduction were collected, i.e. laying dates, clutch size and number of fledglings. Nestling body parameters were measured on the 6th, 9th, 13th and 17th days of their lives. On the 10th and 15th days of nestling life, the number of feedings was counted over a period of 30 minutes. Nests were collected and analyzed for the presence of ectoparasites. It was found that the average number of ectoparasites, both fleas and mites, was greater in nests built on old nest material, and that this number was highly correlated. In further analysis, two possible effects on reproductive output were investigated separately: the presence of old nest material and the abundance of ectoparasites. Clutch size and number of fledglings were smaller in broods from nestboxes containing old nest material, but there was no such relationship to laying dates and nestlings. body parameters (weight, tarsus and wing length). The number of feeding trips on the 10th day of nestling life was higher in .cleaned. nestboxes, but a similar level was achieved by the 15th day in both groups of nestboxes. It was found that ectoparasite abundance did not influence any of the studied parameters of Starling reproduction, i.e. breeding, nestlings. physical condition or number of feedings. This confirmed earlier findings that ectoparasite infestation at a natural level does not affect Starlings. breeding. It seems that the negative effect of the presence of old nest material in nest sites is connected to the costs of site preparation and old nest material removal, which are borne by the females.

3

Forest fragment size affects edge effect in nest predation . experiment with artificial nests

Mazgajski T., Rejt Ł.

Polish Journal of Ecology

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2005

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Vol. 53, nr 2

233-242

EN

Many species react negatively to forest fragmentation. If this process also decreases the abundance of forest predators we expect that birds. broods in small forest patches would be preyed upon only by predators that penetrate from the matrix while broods in larger patches would be also attacked by predators specifically associated with forests. We tested the hypothesis that an increase in forest patch size leads to an increase in predator pressure on nests. Studies were conducted in Central Poland, in an agriculturally dominant area with 6% forest cover and highly fragmented woodlot. Three patch sizes were chosen for the experiment: small (< 20 ha), medium (30 - 50 ha) and large (> 120 ha). One quail egg was placed in each nest. All transects were checked after 13 - 14 days. The highest predation level was found in medium-sized patches, the lowest . in the largest patches. We found a reverse edge effect on nest predation in the largest patches, i.e. a decreased predation risk closer to the forest/matrix border. When comparing our results with other studies, it seems that the manner of classifying forest size significantly affects the results obtained. This may explain the differences in the results of many authors studying this phenomenon.

4

Does the great spotted woodpecker Dendrocopos major select holes for roosting?

Mazgajski T.

Polish Journal of Ecology

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2002

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Vol. 50, nr 1

99-103

EN

Characteristics of Great Spotted Woodpecker roosting holes are compared with those used for breeding. Neither postbreeding nor winter roosting holes differed from woodpecker nests with respect to three species, condition, girth at breast height, cavity height or cavity direction. However, behavioural observations suggested that particular holes might be selected, probably in connection with microclimate condition and predator avoidance.

5

Factors affecting anvils utilization by great spotted woodpecker Dendrocopos major

Kędra A., Mazgajski T.

Polish Journal of Ecology

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2001

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Vol. 49, nr 1

79-86

EN

Three factors which are assumed to influence the frequency of anvil utilization by Great Spotted Woodpecker were studied. They were: (1) microhabitat characteristic, (2) seasonal changes in the cones' availability and (3) size of hammered cones. Anvil location and number of pines Pinus silvestris in 10 m radius (as food resource availability) were described. Hammered cones were collected, counted and measured (length, width). Number of pines didn't influence the intensity of anvil utilization. Particular groups of anvils (main, secondary and ancillary) were exploited throughout the winter in similar way, although in main and secondary anvils there was decrease in the average length of the hammered cones. In particular anvils cones in different sizes were hammered, and intensity of utilization was correlated with the average length and range of length of opened cones. We argue that ancillary anvils are used for opening the cones of specific shape.

6

Nest-site characteristic of Great Spotted Woodpecker Dendrocopos major i central Poland

Mazgajski T.

Polish Journal of Ecology

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1998

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Vol. 46, no 1

33-41

EN

The study was carried out in two nature reserves in Warsaw (central Poland) in 1992-1995. Following aspects of Dendrocopos major nest hole's localisation are describing: tree species, height above the ground, tree trunk girth, condition of tree, tree fragment (in which nest was located) and entrance's exposure. Near all nest's parameters were different between two study areas what suggest that Great Spotted Woodpecker is quite indiscriminate in nest site selection.