No abstract

Nabaglo L., 1986: Common vole numbers in relation to the utilization of burrow systems. Acta theriol., 31, 2: 17-44 [With 2 Tables & 17 Figs.] Population dynamics of the common vole Microtus arvalis (Pallas, 1779), changes in the number of burrow systems, and their utilization were studied in perennial crops of different regions of Poland in [1970][1971][1972][1973][1974][1975][1976][1977][1978][1979]. A multi-year cycle in common vole numbers was found. In the northern region of Poland, maximum peak numbers reached 350 individuals/ha, and in the southern region more than 1000 individuals/ha. An increase in common vole numbers in the multi-year cycle was positively correlated with the number of burrow systems. Highest increases in common vole numbers were observed in autumn, and lowest in spring. Per unit increase in the number of burrow systems, the rate of growth in common vole number increased in the years of peak numbers and decreased in the years of decline. The percentage of occupied burrow systems (colonies) and the number of individuals per burrow system increased with growing population size, but at a declining rate. Multi-year and annual changes in common vole numbers were more affected by changes in the number of occupied burrow systems than by changes in the number of individuals per system. Only in the periods of numbers decline, they mostly depended on changes in the density of colony members. The factors underlying differences in mean numbers of M. arvalis in different regions of Poland are discussed.

1Regina MACKIN-ROGALSKA Spatial parameters of a population of common voles Microtus arvalis (Pallas, 1779) in relation to colonies of burrows, were studied two years for two populations of these animals living in isolated fields of alfalfa each one hectare in extent. The CMR method was used. Trapping sites were set up in the centre of each colony. As the number of colonies increased their distribution changed from random to evenly spaced. In the population where density was high than this change took place almost a year earlier than in the low-density population. Individuals exhibited a tendency to distribution in groups. The number of colonies of burrows occupied by individuals increased asymptotically as population numbers increased. The increase in the number of colonies occupied by females is greater than those occupied by males. The average number of individuals in an occupied colony also increases (in a straight line) with increase in population numbers. It is chiefly the adult individuals which take part in the process of settling up new colonies and settling deserted burrows, and females do this to a greater extent than males. The majority of the individuals entering the population (about 90%) increase the density of already existing colonies. Spatial penetration of voles varies with the season and is higher at times of low population numbers than when these are high. Males were found to move over larger areas than females, and the same applies to older individuals as compared with young ones. The greatest differentiation in individuals from the aspect of spatial penetration was found during the year preceding the year of maximum population numbers.

R., 1984: Trappability and the distribution of individual captures in a common vole population. Acta theriol., 29, Trappability and the distribution of individual captures were examined for three populations of the common vole Microtus arvalis (Pallas, 1779). Trappability was generally low, but relatively higher in summer than on the turn of spring and summer and in autumn. In summer, the trappability of females was higher than that of males. In other periods this difference disappeared. Trappability was lower on grids with low than tall plant cover. The distributions of individual captures were skewed, with the highest proportions of individuals captured only once. The empirical distributions differed from the corresponding Poisson distributions. It is indicated that more efficient methods of common vole trapping should be developed. The relevance of trappability study in the M. arvalis population to analysis of social structure and individual differentiation in behaviour among voles is discussed.

The variability in the mandible dimensions has been investigated in bats of the genus Plecotus Geoffroy, 1818 from Central Europe. The material consisted of 100 individuals of P. auritus and 100 individuals of P. austriacus. The variability in the mandible length appeared to be relatively low in both species (Cv = 3.41-3.99), whereas that in the height of the ramus mandibulae was slightly higher (Cu = 4.93-8.62). For both species the common values of the measurements of the mandible length are found in 10.8-11.0 mm classes, which contain 4 per cent of P. auritus and 18 per cent of P. austriacus. As to the height of the ramus mandibulae, the common range for both species falls to the 3.2 mm class (3 per cent of P. auritus and 4 per cent of P. austriacus). A complete separation of both species can be done by simultaneous comparison of two dimensions using the diagram of their correlation considering morphological characteristics of the mandible. This method may find practical application in indentifying fossil materials or those in owl pellets.