One of the delights of late April and early May is the return of the song of warblers as they arrive from Africa. Some like the Willow Warbler seem to be everywhere and may number in excess of a quarter of a million pairs in the county, others like Lesser Whitethroat and Reed and Grasshopper Warbler take some finding with only two or three hundred pairs likely to be present.
The scarcest in Cumbria, and one of the last to arrive, is the Reed Warbler. It is very much at its northern limit here but its numbers are mainly limited by the availability of suitable habitat – phragmites reed beds are not common and they tend to dry out and disappear over time.
Numbers have increased significantly over the last 30 years since the first colonisation of Siddick Pond on the west coast. Now it can be seen regularly at many lakeside margins where small areas of reed occur – for example at Bassenthwaite, Rydal, Grasmere, Cavendish Dock (Barrow), and Urswick tarn.
More likely to be heard than seen, the species announces its presence with its rhythmic song, more even and less raucous than that of the Sedge Warbler (which also occupies other habitats as well as reeds). While the latter often sings from the top of a bush in full view giving good views of its eyestripe and orange mouth (see right), male Reed Warblers tend to sing from the bottom of the reeds, only climbing to the top in calm bright weather to provide an opportunity to see them and snatch a photo.
If seen, the Reed Warbler is fairly non-descript in appearance, looking very much as you would expect a brown and white warbler to look. Males and females look similar. It can share the same habitat with Reed Buntings, although probably only one pair of the latter occupy the same area of reeds as six or more pairs of Reed Warblers. The female Reed Bunting has similar colouring but has a more stripey appearance and distinctive white moustache.
The Reed Warbler is one of the last migrants to arrive, usually in early May in Cumbria. The nest, attached at the base of some reeds, is a very deep cup, designed to keep the eggs safe when the reeds sway in windy weather. Where they occur, densities can be very high, with each male holding a territory of only a few square metres. Nearby Willow trees often provide a good supply of caterpillars for the young, which can be seen in June.
Reed Warblers return to Africa in a sereis of short hops which increase in length until the last large hop over the Sahara! In complete contrast the Sedge Warbler somehow builds up enough fat reserves to make the trip in one non-stop flight lasting a couple of days!
In contrast the Willow Warbler is the most abundant warbler by far, being found in almost every tetrad in the county except those on fells above about 300 metres. They are not fussy breeders and use almost any habitat that provides cover for the nest. As their characteristic song is often uttered from exposed branches they are also the easiest warbler to see.
The Common Chiffchaff is almost identical in appearance to the Willow Warbler but has a totally different song and is more choosey about its habitat, being absent from the hilly parts of the county. Some members of this species overwinter in Britain, but those that do migrate are reknowned for the ability to arrive back in the same tree from whence they left! With the Willow Warbler, it is usually one of the first migrants to arrive back, and I am disappointed if I don’t hear “chiff-chaff-chiff-chaff” at the end of the road before the end of March.
Next in abundance in the county is probably the Whitethroat. Numbers seem to have recovered well now, although periodic droughts in the winter quarters of West Africa take their toll. Any bit of scrub around the coastal plains of the county will probably hold several pairs of this species, which are usually easy to see once their presence is announced by the scratchy song.
Blackcap and Garden Warbler share very similar distributions and numbers in the county and, annoyingly, very similar songs. They can both be hard to spot, especially once the leaves are fully out as they tend to sing from less exposed branches, but if seen are quite distinctive of course.
The Wood Warbler is my favourite of the bunch and seems to be suffering something of a serious decline and is now quite hard to find – it therefore earns its OWN PAGE on the website!
Finally, the two that are almost as scarce as the Reed Warbler in the county are the Grasshopper Warbler and the Lesser Whitethroat. Both have similar distributions around the lowland coastal regions of the county but are never very common (a few hundred pairs at max.). Grasshopper Warbler is usually picked up by sounding like a very big grasshopper or the unwinding reel of a fishing line! However they are frustratingly difficult to pinpoint as a singing male turns its head from side to side to maximise its effectiveness (see photo). They prefer long matted vegetation, like marram grass. Good sites include Walney, Allonby/Maryport and Geltsdale. Lesser Whitethroat has quite different habitat requirements to Whitehroat, preferring hedgerow trees and bushes with patches of dense undergrowth nearby for nesting. This dapper bird lacks the rusty brown wings of its cousin and is usually first picked up by its rattling call. Askam/Hodbarrow on either side of the Duddon and North Plain Farm/Campfield Marsh on the Solway seem to be the current strongholds.