Organization Lundy Bird Observatory

Royal Air Force (national service)

Leeds & District Bird Watchers Club

Yorkshire Naturalists Union

Skokholm Bird Observatory (warden | 1954-1957)

Fair Isle Bird Observatory (warden | 1957-1963)

British Trust for Ornithology (migration research officer | 1963-1966)

Nature Conservancy (1966-1973)

Nature Conservancy Council (1973-1988)

Wildlife Surveys Wales (1988-1994)

Welsh Kite Trust (trustee | 1996-2012)