Unfortunately the cover got a bit damaged at the left side, but the stamps are undamaged and that's what counts!
The two stamps on the cover are part of a serie of 4 WWF stamps on the Osprey (Pandion haliaetus).
The bird is a cousin of the eagle and is a carnivore. The birds can reach a weight up to one and a half kilo.
As we can suspect from the name and the stamps, the birds are hunting on fishes. Unlike most other fish eating birds, these birds catch the fish with their legs, which makes the hunting very spectacular.
Osprey is a protected animal species in Poland. At this moment, only 30 couples of ospreys live in Poland, mainly in the north of the country.
Also notice the very nice postmark on the envelope, which apparently commemorates '660 years of the town Puck'. Puck is an old fisherman's town in north-west Poland.
