During his tour of the islands in 1774 Low (cited in Pennington et al.
2004) states that he saw ‘Tomis’ (Puffins) on Foula.
From the 1800s – mid 1900s, Puffins were found by a
number of observers such as Raeburn (cited in
Pennington et al. 2004) and V&V (cited in Pennington et al. 2004) to be a
common breeding bird in their many thousands.
In 1969 John Holbourn estimated
the breeding population to be about 50,000 pairs (Furness, 1983).
During
a census count for Operation Seafarer between 1969 and 1971, Foula was one of three colonies found to contain over
10,000 pairs (Cramp et al. 1974).
In 1976 the total number of breeding burrows was estimated
at 70,171 but by 1987 48, 000 occupied burrows was reported (a 32% decline c.f.
1976).
The
most recent population estimate was between 20,000 and 25,000 pairs (Harvey et
al. 2001).
Breeding success since 2000
has been poor to very poor. This recent decline in breeding success is strongly
correlated with a lack of their staple diet of sandeels.
In recent years very few adults have been seen carrying food, and those that
have been observed were carrying pipefish.