Seagull

Seagulls were birds that were exclusive to the planet Earth. They were native at least to coastal England. The Eighth Doctor knew he was on Earth when he heard seagulls. (AUDIO: Island of the Fendahl)

In 2013, the widespread overnight death of many fish in Ambermouth harbour, caused by silicon quartz in the water, affected the seagull population. Gulls gorged on the fishes' bodies to the point where they couldn't fly. Some time after, they too died, and their corpses developed growths of silicon quartz. (AUDIO: Eldrad Must Die!)