EN
301 birds have been investigated in order to discover Syngamus trachea; they all belonged to 4 families of the passerine class, thus to the Corvidae, Sturnidae, Fringillidae and Turdidae. Parasites have been found in 5 representatives of the Corvidae family, viz. in 3 crows (Corvus cornix) and in 2 rooks (Corvus frugilegus). It results from the investigation performed that the main role as hosts of the Syngamus trachea parasite play the birds from the Corvidae family, 5 per cent of which were infestated with Syngamus trachea and the authors are of the opinion that the poultry farms ought to be better proticted against the latter birds.