Hi, recently in New York I saw a pigeon by the Hudson river. It seemed to have flight feathers growing out of its legs, making walking extremely difficult. Is this a known mutation? Is the Hudson river producing biplane pigeons?
I saw this kittiwake flying upside down (see photo) in Norway's Svalbard archipelago - about 79 north - while we were stuck in the sea ice. This and other kittiwakes were feeding on polar cod (about 13 centimetres long) that had become uncovered as our ship broke through the ice.
What is it doing and why? How many other birds can do this?