Kivonat:

We studied Great Tits and Blue Tits during six winters in a marshland in Central Hungary. The number of wintering Tits increased during the study. Tits were found to be residents, immigrants and floaters. The number of immigrants decreased in mid-winter in both tit species, while the number of residents increased. The number of immature floaters changed parallel to that of immigrants, but the number of adult floaters was low and did not change considerably during winter. For both Great and Blue Tits the presence of nest-boxes and artificial feeding increased the overwintering numbers, and for the Blue Tit the effect of temperature was also significant.