L. Forró - É. Murai szerk.: Miscellanea Zoologica Hungarica 6. 1991 (Budapest, 1991)

Bankovics, A.: Avifauna changes of the Kis-Balaton Reservoir area

1. There is one species, the Red-crested Pochard (Netta rufina), which is new as a breeding bird for the whole Hungarian avifauna. Its first breeding was proved by E. FUTÓ in 1986 (BANKOVICS 1988, FUTÓ 1990). 2. There are some species, which settled in relatively greater number in the first years, but in spite of the successful breeding, they settled in smaller number in the following years, and eventually disappeared from the area, e.g. Podiceps nigricollis, P. griseigena. 3. There are some species, which settled in greater number in the first years, but after that the populations declined, e.g. Anas strepera, Aythya fuligula, Chlidonias niger. 4. Some species settled in the first years, but after unsuccessful nesting attempts and/or inappropriate conditions, and since the second year they have disappeared, e.g. Charadrius dubius, Himantopus himantopus, Recurvirostra avosetta. 5. Many of the new settler species have established a strong and stable population from the first year to the present, e.g. Anser anser, Aythya ferina, Aythya nyroca, Fulica atra, Larus ridibundus, Sterna hirudo. 6. Some species have settled in small number in the first year and have gradually increasing breeding populations, e.g. Podiceps cristatus, Chlidonias hybrida. Detailed descriptions Fam. Podicipedidae Black-necked Grebe (Podiceps nigricoUis) The breeding population size of this species shows an interesting trend. It has established rather strong colonies in the first year (1985) of the inundation. In the second year (1986) the number of breeding pairs further increased, but from the third year (1987), it began to decline (Table 4). In the years 1989 and 1990 it has not bred here at all. Based on its occupation pattern it seems to be a pioneer settler on fresh flooded areas. This character was already observed earlier. KONCZ (1967) reported its colony from a flooded maize field at Fülöpháza in 1966.1 have found new colonies of this species in a newly established and first-flooded fish pond at Csaj-tó, Tömörkény in 1970. Red-necked Grebe (Podiceps griseigena) It is the rarest breeding species of grebes in Hungary. Its main breeding sites are in the Great Hungarian Plain. In the western part of the country its nesting was proved at Irmapuszta and Tihany near the Lake Balaton (KEVE 1976). The first breeding in the Kis-Balaton Nature Reserve was only proved in 1989. Surprisingly, in the reservoir were found two breeding pairs by E.FUTÓ in the first year (1985), and there was at least one breeding pair in both 1986 and 1987 (Table 4). Great-crested Grebe (Podiceps cristatus) I think its increasing number correlates to the increasing trends of fish populations which have occupied the ponds naturally and by introduction. A few breeding pairs were already observed in 1984 after the experimental inundation in May. Later the P. cristatus popopulation increased gradually (Table 4).