She served as the founding and honorary Secretary of the British Trust for Ornithology's Bird-Ringing Committee in 1937 and continued to work on ringing until 1963.

Born in Plymouth, the younger daughter of Sir Edward Pemberton Leach, Elsie grew up in a well-connected family that moved across the United Kingdom and overseas.

[2] An interest in birds was sparked off through her friendship with Emma Louisa Turner which led to a meeting with Harry Witherby in 1930.

Her skills at ringing and care in maintaining records were well known and her memory and ability to recall recoveries helped in her work.

Her work was recognised by the award of the Bernard Tucker Medal in 1954 and she was appointed a Member of the Order of the British Empire (MBE) in the 1954 Birthday Honours.