Spurn, a designated Heritage Coast, is a nature reserve, owned since 1960 by the Yorkshire Wildlife Trust and covering 113 hectares above high water and 181 hectares of foreshore. The mud flats are an important feeding ground for wading birds, and the area is a significant site in Europe for observing migrating birds.
Many uncommon species have been sighted there, including once a Black-browed Albatross. More commonly, birds such as wheatears, Whinchats, Common Redstarts and flycatcherss alight at Spurn on their way to breeding grounds elsewhere. The peninsula is made up from sand and shingle eroded from the Holderness coastline washed down the coastline from Flamborough Head.
Material is washed down the Holderness coast by longshore drift and accumulates to form the long, narrow embankment in the sheltered waters inside the mouth of the Humber estuary. It is maintained by plants, especially Marram grass (Ammophila arenaria). Waves carry material along the peninsula to the tip, continually extending it. However, as the peninsula grows, it narrows. When the sea cuts across it, and everything beyond the breach is swept away, only to eventually reform as a new spit pointing further south. This cycle of destruction and reconstruction occurs approximately every 250 years.