 During breeding season the bluffs are dense in birds arriving, departing and feeding in the waters below.Sound levels from birds have been measured as high as 69 dBA for a one-hour interval.As of 2005 about 18,000 breeding pairs of kittiwakes ("Rissa tridactyla") return to Fowlsheugh each year, making their nests on some of the most vertical parts of the landscape from muck, seaweed and local grasses.