All bird ringers in the UK are licensed by the British Trust for Ornithology (BTO). The Northumbria Ringing Group (NRG) welcomes enquiries from anyone interested in becoming a trainee to work towards a ringing permit. There are two types of permit available, General and Specific. The General permit allows the ringer to ring all species subject to prohibitions in force at the time and the Rules of the Ringing Scheme. Specific permits allow the ringer to define a special field of interest, when they ring only those species or groups of birds or areas specified e.g. nest box ringing.