Sunbathing (or "Sunning") is a common bird behaviour. There are many theories as to what benefit the birds gain from this behaviour. At the simplest, it may be to warm up on cool days but it is also important for feather health. Sunning probably helps to get rid of feather parasites. It is also possible that it helps to produce vitamin D from the oil secreted by the preen gland at the base of the tail. This wren certainly appeared to be revelling in the spring sunshine at the Wolseley Centre, The Staffordshire Wildlife Trusts headquarters, today.