TICKS (ACARINA, IXODIDAE) OF WILD BIRDS IN THE EBRO MIDDLE BASIN (NORTHEAST SPAIN)

Living birds (n = 1776) were trapped and their ticks removed in Ebro M iddle Basin (N.E. Spain) between January 1990 and July 1991. Positive hosts were T. troglodytes, Prunella modularis, Erithacus rubecula, Pho enicurus ochruros, Turdus merula, T. philomelos, Sylvia atricapilla, P hylloscopus collybita, Parus major, Certhia brachydactyla, P. pyrrhoco rax, Fringilla coelebs, Emberiza citrinella, E. cirlus, E. cia and E. schoeniclus. Ticks collected (N = 255) for this study belong to the sp ecies Ixodes ricinus and Haemaphysalis punctata (immatures only), Ixod es frontalis (all stages) and Hyalomma marginatum (nymphs). The estima ted prevalence for some bird species (Sylvia atricapilla, Phylloscopus collybita, Parus major and Pyrrhocorax pyrrhocorax) is very low, but others like Erithacus rubecula, Turdus merula and Turdus philomelos it reaches values of about 20 % or even higher. Most of the cases of par asitism by ticks are due to Ixodes frontalis. This tick can attach a w ide range of hosts, although Erithacus rubecula and Turdus philomelos are the commonest. With regard to Ixodes ricinus, Turdus merula seems to be the most important carrier, whereas Emberiza cirlus may be the m ain host for Haemaphysalis punctata.