RSPB Film from the sadly long gone annual RSPB Film Shows! Wild Birds Of Teesmouth from 1966.

https://player.bfi.org.uk/free/film/watch-birds-of-teesmouth-1966-online

This was an RSPB Film from the now sadly long gone RSPB Annual Film Shows. This RSPB Film first shown at the Annual Film Show in1966 called Wild Birds of Teesmouth. Many decades before Saltholme which first opened in 2009.