In the years 1989-1990 53 nests of D. urbica and 47 nests of H. rustica were collected from Resko (Province Szczecin). In 95 nests 2483 ectoparasites representig 3 species: C. hirundinis (73,1 %), Oe. hirundinis (26,5%) and C. gallinae (0,4%) were found. The highest mean number of specimens per nest was observed in the nest of D. urbica (29,5) and the lowest in nest of H. rustica (19,5). The highest (57) of nests was inhabited by 2 parasites species, 35 nests - by 1 and 3 nests - by 3 species. The highest mean number of ectoparasites per nest of D. urbica was noted in December and in nest of H. rustica- in October.
In 1993 43 nests of Goosander from the Jasień Lake near Bytów were collected and checked on fleas presence. Ceratophyllus gallinae, the only one fleas species, was found in 60,5% nests. Among nests where the fleas were found the most frequent were those inhibited by 1-10 specimens of fleas (12 nests). The highest mean number of fleas per nest and the highest percentage of nests with fleas were noted before the breeding season has started (in March) and the lowest after the fresh brood in May. More fleas were noted in nests with successful broods. M. merganser was not yet noted in Polish literature as a host of C. gallinae in Poland.