Declining Wood Warbler
Reports
The British Trust for Ornithology Breeding Bird Survey for 2024 published in May this year shows a 55% decline in breeding Wood Warbler in the UK in the last ten years and an 80% decline in the last thirty years. It is one of the fastest declining species in the United Kingdom.
This is reflected on Arran. Twenty years ago, when I started as bird recorder, there were areas where I could go and regularly listen to Wood Warbler singing in the summer. Even at that time, these were localised unlike the more widespread similar species, Willow Warbler and Chiffchaff. This year there have only been two reports of Wood Warbler singing briefly. In 2024 there were no Wood Warbler reports for Arran whereas reports of both Willow Warbler and Chiffchaff were each well over one hundred.
This decline has led to Wood Warbler being Red Listed as a bird of conservation concern. While the reasons for this decline are not fully understood, factors like climate change and habitat loss in both the UK and their African wintering grounds are suspected.
Various studies are giving some insight into Wood Warbler. Geo trackers for example have revealed a complex migration. Wood Warblers departing breeding sites in the UK in late July, stop for most of August in central southern Europe, then cross the Sahara by a non-stop night and day flight immediately followed by a short stop, before then migrating west to a longer stopover in the Sahel. The final movement takes them further west to an area of West Africa covering Guinea, Sierra Leone and Liberia. That’s stopovers for at least three weeks in three distinct regions, in central southern Europe, in the Sahel and in the humid zone of West Africa.
Studies in the UK, including Scotland, indicate that this summer breeding visitor is mostly found in central and western areas of Scotland where it is associated with closed canopy oakwoods, beech, birch and ashwoods. A relatively sparse understorey is essential. Although it feeds and sings in the canopy, it nests on the ground requiring low and open vegetation where it is vulnerable to ground and avian predators including disturbance by dogs.
One of the ways of distinguishing Wood Warbler from the more familiar Chiffchaff and Willow Warbler is song. Indeed, the Wood Warbler’s scientific name ‘sibilatrix’ means the whistler. The trilling song is performed by the male with gusto, head raised, bright yellow throat puffed out and body all aquiver. Check out this link Bird sounds, Wood warbler singing and chirping in the spring forest on YouTube
It was Gilbert White, curate of the Hampshire village of Selborne, who first distinguished them as three separate species. Gilbert White was one of the first English naturalists to make careful observations of his surroundings and record these observations in a systematic way. He believed in studying living birds and animals in their natural habitat, which was an unusual approach at that time, as most naturalists preferred to carry out detailed examinations of dead specimens in the comfort of their studies. The result of all his detailed observations was the publication in 1789 of his book called ‘The Natural History and Antiquities of Selborne’. Since that time, it has never been out of print, one of the most published books in the English language.
Over two hundred years ago Gilbert White described the song as “sibilous shivering”. It would be wonderful to hear the song this summer. If you do, please let me know.
Over two hundred years ago Gilbert White described the song as “sibilous shivering”. It would be wonderful to hear the song this summer. If you do, please let me know.