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

KOVÁCS GY., NAGY Á. & WINKLER D.: WATERFOWL POPULATION SURVEY 267 Table 1. continued Species Av N Do De (ind./ha) c Status Charadrius dubius 0.7 13 0.1% 0.0 5% R Charadrius hiaticula 0.9 17 0.1% 0.0 16% A Pluvialis squatarola 2.7 52 0.3% 0.0 11% A Vanellus vanellus 38.3 727 4.0% 0.1 53% C Calidris ferriiginea 0.3 6 0.0% 0.0 5% R Gallinago gallinago 3.8 72 0.4% 0.0 32% A Lymnocryptes minimus 0.7 13 0.1% 0.0 5% R Philomachus pugnax 1.1 20 0.1% 0.0 5% R Tringa erythropus 8.1 154 0.9% 0.0 26% A Tringa totanus 1.3 25 0.1% 0.0 16% A Tringa stagnatilis 0.1 2 0.0% 0.0 5% R Tringa ochropus 1.3 24 0.1% 0.0 16% A Tringa glareola 0.9 17 0.1% 0.0 16% A Actitis hypoleucos 0.8 16 0.1% 0.0 37% A Limosa limosa 0.2 3 0.0% 0.0 5% R Lartis ridibundus 105.7 2009 11.2% 0.3 89% C Larus canus 1.5 29 0.2% 0.0 26% A Larus cachinnans 33.4 635 3.5% 0.1 84% C Sterna hirundo 1.4 26 0.1% 0.0 26% A Chlidonias hybridus 2.2 41 0.2% 0.0 21% A Chlidonias niger 0.1 1 0.0% 0.0 5% R Breeding species The most appropriate nest sites for waterbird species can be found primarily on the anterior settling ponds as well as in the reed edges of the reservoir. The anterior settling ponds have been siltated almost completely since the establishment. Hence a habitat patch mosaic structure is characteristic for this part of the study area with a vegetation consisting of sedge and reed species. The open water area is limited to 3-4 hectares; however, a significant portion of the breeding species is found in this 50 hectare habitat. While estimating the number of breeding pairs, it has to be taken into account that certain species remain hidden during such observation based surveys. These kind of „hidden species" would be the Water Rail, the Common Gallinule and the Spotted Crake. Breeding population of the other species may be estimated with fairly high accuracy. On the Marcali reservoir a total of 14 breeding species were recorded (Table 2), 4 of them are strictly protected, 7 protected, 4 are threatened Europe-wide (SPEC 2, 3), while the Ferruginous Duck is listed threatened worldwide (SPEC 1) (BirdLife International, 2004). Population dynamics, density, dominance-structure The number of individuals was notably high (3867 ind.) at the end of January. Other months with high number of birds observed (1100-1800 ind.) were March, April, July