Ábrahám Levente (szerk.): Válogatott tanulmányok VI. - Natura Somogyiensis 19. (Kaposvár, 2010)

KOVÁCS GY., WINKLER D. & FARAGÓ S.: A kárókatona fészekalj és tojásméret vizsgálata a Kis-Balatonon és a Nagyberekben

268 NATURA SOMOGYIENSIS Table 2: Estimated breeding population of waterbird species on the Marcali reservoir (2007) (P - protected, SP - strictly protected, SPEC - Species of European Conservation Concern) Breeding species Breeding pairs National legal protection status SPEC categories Tachybaptus riificollis 2-4 P Non-SPEC Podiceps cristatus 2-7 P Non-SPEC Botaurus stellar is 1-2 SP SPEC 3 Ixobrychus minutus 1 SP SPEC 3 Nycticorax nycticorax 8-20 SP SPEC 3 Cygnus olor 1 Non-SPEC Anser anser 3 P Non-SPEC Anas plathyiynchos 4-5 Non-SPEC Aythya ferina 1-2 P SPEC 2 Aythya nyroca 1-3 SP SPEC 1 Rallus aquaticus 2-10 P Non-SPEC Porzana porzana 1-? p Non-SPEC Gallimila chloropus 1-? p Non-SPEC Fttlica atra 6-20 Non-SPEC and October (Fig. 1). Number of birds was significantly less (-200 ind.) at the beginning of summer and at the end of December. In regards to seasonal evaluation, average number of individuals was the highest (1721 ind.) in the early spring period while total number of individuals was the highest (6406 ind.) in the winter period (Fig. 2). Measures of density follow the dynamics of number of individuals, which generally had a low value (on certain observation days 0.5-9.6 ind./ha) averaging at 2.4 ind./ha (Fig. 3). According to the dominance structure, the Cormorant was the only species dominant (50%) in all seasons. Apart from the winter period, the Black-headed Gull also occurred with significant number of individuals. Considering the entire study period, the absolute dominant species (Do=20.4%) of all was the Greater White-fronted Goose appearing in huge flocks in winter. 4000 3500 3000 * 2500 I 2000 1 1500 500 HJj|.ii SP SU AU W ES ST SP SU AU W ES ST Fig. 2: Number of individuals observed on the Marcali reservoir during the 07.04.2007-03. 26. 2008 period; Fig. 3: Seasonal average of number of individuals; Fig. 4: Seasonal density (ind./ha) (SP - spring, SU - summer, AU - autumn, W - winter, ES - early spring, ST - study period average)