Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)

Fenyősi, László: Studies of avian communities along river Drava, between 2000-2004 (Aves) - Madárközösségek vizsgálata a Dráva somogyi szakasza mentén, 2001-2004-ben

132 NATURA SOMOGYIENSIS Table 12.: Occurring waterfowl species and their specimen numbers in the Drava section between river kilometres 199-184, in 2001 Species 03/02/2001 07/03/2001 07/04/2001 12/10/2001 09/12/2001 Tachybaptus ruflcollis 8 14 9 Podiceps cristatus 1 Phalacrocorax carbo 44 35 2 7 13 Egretta alba 9 3 3 6 Ardea cinerea 3 2 18 2 Cygnus olor 10 2 8 11 Anas crecca 41 60 Anas platyrhynchos 3810 8 27 1355 Bucephala clangula 1 3 Mergus merganser 1 Haliaeetus albicilla 3 1 2 Pandion haliaetus 1 Circus aeruginosus 1 Gallinula chloropus 1 Fulica atra 4 1 Vanellus vanellus 54 1 Charadrius dubius 1 Actitis hypoleucos 4 Tringa ochropus 6 1 11 4 Tringa nebularia 1 Alcedo atthis 2 4 2 Total 3940 118 52 41 1470 minutus and Gallinago gallinago are occasional nesters. It is remakable from the complete list that the proportion of migrating species and those visiting the area for feeding is much higher (69.9%) than those of breeding there (30.1%). The monitoring of wintering and migrating water birds on the Drava section between Bélavár (199 river km) and Heresznye (184 river km) Wintering and migrating water birds on the Drava section between Bélavár (199 river km) and Heresznye (184 river km), as well as in side-branches associated with this river section were monitored in 2001-2004, from autumn to spring (from September to March). Bird censuses were made from ashore (Hungarian areas), and from boat (Hungarian-Croatian areas). The results of the recordings are presented in Tables 12-15, from where it appears that during 24 samplings, a total of 30 species belonging to the studied taxa were observed. As our results suggest, higher abundance values and species numbers in this Drava section can be expected in the period between DecemberFebruary; the highest values were observed on 20th January 2002, with 15 species and 4650 individuals. Based on the recordings, the most frequent A. platyrhynchos (91.7%) is followed by Phalacrocorax carbo (79.2%), Egretta alba (79.2%), Ardea cinerea (75%o), Cygnus olor (62.5%o) and Haliaeetus albicilla (54.2%). It was found that 92%) of all bird specimens observed (17 884) were Anas platyrhynchos, therefore this species turned out to be the absolutely dominant one.