Lanszki József - Ábrahám Levente (szerk.): Magyarországon élő ragadozó emlősök táplálkozás-ökológiája - Natura Somogyiensis 4. (Kaposvár, 2002)

Feeding ecology of mammal predators living in Hungary The present study features seven carnivores examined between 1991 and 2001 namely, otter (Lutra lutrd), stoat (Mustela erminea), stone marten (Martes foina), pine marten (Martes martes), badger

(Mêles mêles), red fox (Vulpes vulpes) and golden jackal (Canis aureus). The areas studied are in the South-western part of Hungary; contain cultivated agricultural lands (the region of Fonó Fishpond, Mike-Csököly and Kétújfalu), forest (Lankóci Forest at Gyékényes), or forest surrounding pond systems (Boronka Nature Landscape Area and Petesmalom). The feeding habits of otters was also examined at the aquatic habitats of the Danube-Drava National Park, namely at the Drava River (OrtilosSzentmihályhegy and Vízvár), at backwaters (Bélavár, Babócsa, Kisbók), at lakes (the quarry lakes of Somogy udvarhely) at abandoned fishponds (Barcs-Rigóc/Barcs Juniper Woodland Nature Landscape Area), at canals (Korcsina and Dombó) and stream (Rinya at Babocsa). To study the feeding habits of carnivores was accomplished by analysis of excrements, using more than 10,000 samples. The feeding behaviour of otters and their fish preference was examined at eutrophic fishponds (Fonó Fishpond and Boronka Nature Conservation Area). The correlations coefficients between the otters' fish diet and the available fish stock were generally close. For example at the Fonó Fishpond during a 6 year period, the values received were 0.56 (PO.05), 0.87 (PO.001), 0.93 (PO.001), 0.79 (PO.05), 0.36 (NS), and 0.81 (P<0.001), while during a 2 year period at the Boronka Nature Conservation Area they were 0.02 (NS) and 0.33 (NS), respectively. The occasionally low correlation coefficients indicated that the otters' fish prey selection was determined not only by the availability of species, but also by its size (r

s

=0.70, P<0.01). The fish preference calculations were performed with Ivlev's index of preference (Ej, min.:-l, max.: +1). Regardless of species, the otters avoided (Ej=-0.51) fish heavier than 1000 g, with a preference for individuals weighing between 500 and 1000 g (E—0.79). No substantial or clear preference was observed in the weight range below 500 g (Ej=-0.

02-0.38). The preference for fish in accordance with their characteristic sites of occurrence within the body of water was also significant (P<0.01). They avoided fish living primarily in open water (Ej=-0.64) and to a lesser degree those occurring near the pond bed (Ej=-0.22). They favoured fish inhabiting the area with a covering of aquatic plants (E—0.46) and showed a preference to a lesser degree for fish living in the shallow littoral regions (Ej=0.14). With the cessation of fish farming and the effect of the drastic changes which occurred in the vegetation, the otters fed substantially on the stock of alternative sources of prey such as amphibians and water insects as well as terrestrial animals, and at such time, depending on season, fish became a secondary source of prey. In the aquatic habitats, such as the DravaDistrict region, like the Drava River, the Bares Juniper Woodland Nature Landscape Area, the quarry lakes, the backwaters of Bélavár, Kisbók and Babócsa the primary source of prey consisted offish, provided there was an abundant fish stock.. The occa-