Daily activity rhythm in rodents under natural conditions

Abstract

Investigations on the daily activity rhythms in two species of rodents, Apodcmus flavicollis (Melchior , 1834) and Clethrionomys glareolus (S c h r e b e r, 1780) under natural conditions were carried out from July to September 1959. Animals were trapped in two different environments, in the reserve in the strict sense of the word (Białowieża National Park — BNP, Div. 371) and in the cultivated part of the forest (Zwierzyniec Forest District, Div. 450), for 10—12 days in the middle of each mouth. The biotype of both these localities was the same (Querceto carpinetum Tüxe n R., 1937), that is to say, the deciduous forest consisting mainly of hornbeams, oaks and spruces. Two trapping plots were laid down in both of the localities: one with paths running lengthwise and crosswise, respectively 5 and 10 m apart, with 50 cylinder traps sunk in at the crossings of the paths and the other without paths with 100 double live-traps arranged according to the same pattern. In the latter plot, in each of the 50 points there were 2 double (two-sided) traps, one with a bait and the other without it. Cubes of bread fried in oil were used as a bait. The trapping plots were inspected 12 times a day at even hours. The rodents caught were marked by the amputation of digits and the excision of a notch in the ear and they were set free in the proximity to the trapping plot. In addition, the hair on the head was cut off in bank voles, which made it possible to recognize a specimen marked before and to distinguish it from others, caught for the first time, at a glance. Each catch was recorded, the animal identified, and the date, hour, and place of catching taken down. Trapping and marking were done by students of zoology during their field training.