This is a chiffchaff video.
From Wildlife Extra:
Scotland’s warbler population rockets – but worries over kestrels
July 2010: Two species of woodland warbler are doing far better in Scotland than the rest of UK, according to the latest population survey, but while this news is encouraging there are concerns about the decreasing population of roadside raptor the kestrel.
Across the UK as a whole, there has been a 43 per cent increase in the numbers of chiffchaffs and 61 per cent boost for blackcaps – but in Scotland breeding populations have rocketed.
Chiffchaff & blackcaps
Between 1995 and 2008 the chiffchaff population nearly trebled in Scotland while the numbers of blackcaps nearly doubled. This is great news for both medium-distance migrants, which winter in southern Europe and Africa. It is thought that the birds that breed in Scotland spend the winter in different areas to English breeders, and so may experience different conditions on their winter quarters.