Generalised feather abnormalities (pinching off syndrome) in free-ranging White-tailed sea eagles (Haliaeetus albicilla) from Germany

Since 1975 free-ranging White-tailed sea eagle nestlings with a generalized feather abnormality (pinching off syndrome) are found in Germany. The birds suffer a profound abnormality of the feathers, especially of the primaries, secondaries and rectrices. The feathers are often too short; the ventral surface of the rachis is covered by keratin depositions and/or splitted. The affected nestlings loose the first feathers already in the nest. The new developing feathers are much shorter and more deformed than the feathers of the first generation. Due to the feather changes the birds are not able to fly and are mostly found on the ground near the nest site. Birds that were kept in captivity for a longer period (up to ten years) suffered a deterioration of the feather quality and rehabilitation was not possible in any case. At the moment the cause and a possible therapy of this disease are unknown.