O. G. Dely szerk.: Vertebrata Hungarica 8/1-2. (Budapest, 1966)

Topál, Gy.: Some observations on the nocturnal activity of bats in Hungary 139-166. o.

Thus the various species are generally well recognizable. By sampling, together with banding as well as nettings, I was able to establish definitely that the population was yearly composed of mainly the species Myotis myoti

s, Rhinolophu

s euryal

e

, and Miniopterus schrelbers

i. In the summer population, there occurred also some few specimens of Myotis emarglnatu

s

. Early spring and spring observations are in essentials missing from all points of view. The major part of the data were collected in this locality during the summer. It was interesting to note that in the beginning of August, 1957, the number of the complete population had nightly decreased by about 200 specimens, although I have attempted to obviate the slightest disturbing of the bats and had not even entered the cave for some days. However, I have banded the bats on 3 August, and the specimen number of the population, anyhow unstable prior to the large-scale autumnal migration, decreased on the next morning by 500 as related to the preceding evening. I have observed in September that it is a certain amount of Miniopterus schreibersi which remain for the longest time in the cave. I remark only in parentheses that this cave is hardly suitable as winterquarters. In November, aside of a smaller group of Miniopteru

s , sporadic numbers of Myotis oxygnathu

s and Rhlnolophus hlpposidero

s were found. It is connection with probably the shape of the aperture and entrance chamber of the cave that - I have observed this invariably - the bats, preparing for their exit, were wheeling around in always the same cour se, namely - when looking toward the opening - they approached it from the left and turned back towards the right. Until darkening had not reached the grade suitable to them, increasingly more and more animals described this revolution. Some had occasionally taken a flight to the outside, but until the commencement of the true aperture, they had invariably returned to the cave, as was also shown by several authors.