An Official Statistics Publication for Scotland: Index of Abundance for Scottish terrestrial breeding birds, 1994 to 2023

Over the long term (1994-2023), the combined abundance for 66 species of terrestrial breeding bird increased steadily till the mid-2000s, but has subsequently declined. It is currently 10% higher than in 1994 (using the smoothed indices).

Over the short term (2022-2023), using the unsmoothed indices, the urban bird index remained stable (i.e. has not changed more than 5% since last reported). The all-species, farmland, woodland and upland bird indices increased (6%, 11%, 6% and 7% respectively).

Analysis of habitat specific trends did show some change over the long term: the woodland bird index increased by 58%; the farmland bird index increased steadily up to the late-2000s, in 2023 it was 7% higher than in 1994. Upland birds decreased by 20% over the same period. The trends differ between species and may be due to factors on the breeding areas in Scotland or, for migratory birds such as whitethroat, conditions on migration routes or wintering areas. Climate change is affecting some bird populations with evidence of birds shifting northwards (e.g. willow warbler). Declines in some common finches (greenfinch and chaffinch) have been linked to the disease Trichomonas gallinae.

Ends.