Studies were made from 1965-1970 within the Kampinos National Park forests near Warsaw and surrounding area, for the purpose of ascertaining the possibility of limiting the amount of damage caused by w ild boar, Sus scrofa. Linnaeus, 1758 on commercial land. The purpose of managing the population was to bring about a greater num ber of older individuals. The population was regularly supplied with supplementary food, records were kept of the degree to which use was made of the food, feeding times, along with damage done by the ani mals to crops. A total o f 507 individuals was marked, obtaining 2640 captures and 6180 separate observations. The supply of food brought about an increase in population numbers from about 30 to 250 animals (within an area of approx. 2.5 thousand ha of wooded land), follow ed by a decrease of about 50-70 individuals. The population consisted of settled and migrating (ephemeral) individuals. Some of the individuals were found to migrate over a considerable distances (over 250 km). The number of females in the population exceeded the number of males, particularly in the older age classes. Increase in population numbers resulted in the animals feeding on supplementary food during the day time hours also. Consumption of supplementary food decreased damages in spite of increasing the population numbers. The wild boar caused

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The food supply of two populations of Clethrionomys glareolus (Sehreber, 1780): one living in forest on a 4 ha lake island, and the other inhabiting an open forest, was exprimentally increased by supplying oats ad libitum for a period of two years. The food was supplied in wooden boxes, which on the island were arranged in a grid of squares, each 15X15 m. In the open forest the boxes were placed on two plots each of 2.7 ha: (1) intensive supplementation with the grid of boxes 7.5X15 m, and (2) extensive supplementation with the grid of boxes 30X30 m. Population parameters were estimated by the CMR method each individual being marked. Food supplementation caused intensive winter reproduction to such extent that 50% of individuals found in the spring were born during the winter. On the other hand, food supplementation did not affect winter survival, although a few individuals (females) survived two winters. During the winter, sexually active males were heavier than females. The individuals born during the winter promptly become sexually active. A result of the increased food supply was that the population numbers in the spring were 2 to 4 times higher than in control years. A similar situation was observed in the autumn. Hence the food carrying capacity of the habitat is a significant factor affecting the numbers of small forest rodents despite the fact that, as indicated by energy balance studies, they utilize only a small part of food available in the ecosystem.

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Processes oi Incoming, Settlement and Disappearance oi Individuals and Variations in the Numbers of Small Rodents Procesy nachodzenia, osiedlania się i ubywania osobników a dynamika liczebności drobnych gryzoni [With 10 Figs. & 22 Tables] 3 90.

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The density of European hare population on the hunting grounds of Polish Hunting Union Research Station in Czempiń was estimated by regression function of the number of hares caught in subsequent drives. The estimation was based on the catch from 20 sampling areas, the total of 2,361 hectares. The realized production of young from one female was determined and the mortality of foundation stock was estimated from retrapping of marked hares. From these data the optimal yearly take of hares from this population was calculated. Large fluctuations of realized production of young and inaccurate information on the foundation stock mortality make precise foreseeing of these values difficult and consequently, it is necessary to plan the take very carefully in order to maintain the population numbers in autumn on the desired level. Nevertheless, the proposed method together with the studies of realized young production allow correcting the plan of catching for the actual population numbers at the very beginning of catching season.

An isolated population of Clethrionomys glareolus (Schreber, 1780) was investigated over the course of one year. Marking of all trappable individuals and knowledge of the time in which the various individuals were born made it possible to distinguish 5 age groups (cohorts). The maximum participation in the current year's population mass, expressed by the number of individual-days, was that of the early summer cohort (56%), the maximum participation in natality -(53.6%) -was that of the early spring cohort. It was also found that individuals from the early summer cohort were the most numerous survivors to the following year (they formed 75% of the population in the spring). The disappearance rate of the young animals is far higher than that of trappable individuals in the summer. Disappearance of the young of spring and early summer cohorts is lower than that of the late summer and autumn cohorts. Disappearance of the trappable part of the population is lower in the winter than during reproduction.