Chiffchaff

Bird of the Month March 2023: Chiffchaff

I’ve written before about the chiffchaff’s song being a quintessential sign of spring. In fact, I heard my first one of the year just a few days ago. They are one of our earliest returning migrants, but an increasing number are also spending the winter in the UK. Either way, March is an excellent month to listen out for their distinctive ‘chiffchaff, chiffchaff’ song as birds arrive back on their territories.

Sprite of Spring

This small member of the warbler family has an olive-brown upper body and wings, with a paler, yellowish underside. They also have a pale supercilium, or eye stripe. This appearance can mean they are sometimes hard to distinguish from some of their relatives without good views. However, they more than make up for this lack of distinctiveness with their song. Chiffchaffs more or less sing their own names. Sometimes it might get a bit mixed up and sound more like ‘chiff chiff chaff’ or a combination of these sounds, but they still sound like nothing else. Individuals quite often sit at the top of a bush or tree to sing making them easier to see than some of our more skulking warblers.

Chiffchaff
Chiffchaffs often sing from a visible perch

For many of us, the chiffchaff is a welcome early sign of spring. As one of our earliest returning migrants, they are often back on their breeding territories in mid to late March. Unlike their close relatives the willow and wood warblers, they are short-distance migrants to southern Europe and north Africa. Willow and wood warblers, meanwhile, winter south of the Sahara. This means that chiffchaffs have a much shorter and easier journey to get back on their breeding grounds each spring, hence the early arrival.

White’s Warblers

The chiffchaff’s similarity in appearance to some of its cousins caused quite a lot of confusion in the past. Until the late 1700s, the chiffchaff, willow warbler and wood warbler were regarded as one species, the ‘willow wren’. Naturalist Gilbert White, however, was the first to separate them out after recognising their different songs. He was a meticulous observer of wildlife and paid great attention to both appearance and behaviour in order to learn more about the natural world. He realised that while the chiffchaff sings its name, the willow warbler has a descending, melodic song. The wood warbler’s song is a trio of whistles followed by a trill like a coin spinning on a tabletop.

Willow warbler
Willow warblers, like this one, tend to have pink legs to the chiffchaff’s dark ones as well as a more noticeable eye stripe

There are some differences in appearance, as well, although the chiffchaff and willow warbler are particularly similar. When seen well, chiffchaffs usually have dark legs as opposed to the willow warbler’s pinkish ones. Willow warblers’ wings also give a clue to their different migration strategy. They have slightly longer wings, with what is called a longer primary projection. Longer, more pointed wings tend to be found on birds flying longer distances. Willow warblers are often brighter in appearance then chiffchaffs, too. They also have more strongly marked faces with a bolder eye stripe. Although there is a lot of overlap in range, willow warblers are much more widespread when it comes to Scotland, able to breed in more upland areas. Chiffchaffs tend to be more common than their cousins in England. Both breed in a mixture of habitats, from scrub to parks and hedgerows.

Wood warbler
Wood warblers are much brighter birds with yellow faces and very white breasts

Wood warblers are the least common of the three. They breed predominantly in western parts of Scotland and Wales, as well as woods in Dartmoor, Exmoor and the New Forest. They are a much brighter bird altogether. A greenish-yellow back and wings and bright yellow throat contrast with a much whiter belly than the other two species. They are also the fussiest when it comes to habitat, preferring upland woods with mature trees.

Changing Behaviour

Until relatively recently, it was very unusual to see a chiffchaff in winter. An increasing number of birds are wintering here, however, particularly in the southern half of the country. Warmer winters are almost certainly key as it means there are enough insects around to support these birds. The big question is where these birds bred. Are they the same birds that spent the summer here breeding deciding to stay now it is warmer? Or is it a similar situation to that of another warbler, the blackcap? Recent research shows that the increase in wintering blackcaps over the last few decades is down to birds travelling here from all over Europe at the end of the breeding season, rather than UK birds staying.

Siberian chiffchaff
Siberian race chiffchaffs tend to be quite grey looking and have a piping call

Ringing recoveries and observations so far suggest the picture may be similar to some extent. An interesting study by the Rye Meads Ringing Group in Hertfordshire has discovered some clues about their birds, at least. They never retrap any of the chiffchaffs they’ve ringed in the winter when it comes to spring and summer. This shows they are different birds and the possibility that the site’s breeding chiffchaffs now just stay all year can be ruled out. Some birds may well have come from elsewhere in the UK. There are others, though, with plumage typical of the Siberian subspecies, suggesting some are coming here from Russia. Winter ringing recoveries from other projects have involved birds breeding in the north of England and Denmark. What is clear is that many of these birds return to the same wintering site each year.

Ultimately, wintering chiffchaffs are likely to be a combination of British breeders migrating within the UK, as well as birds from further afield.

Spring Herald

Whether you have been lucky enough to spot one of our growing number of wintering chiffchaffs or not, March is the perfect time to listen out for that distinctive song. As poet Edward Thomas wrote, that simple song surely sounds like ‘every note had been the hammering of a tiny nail into winter’s coffin’.

Common chiffchaff
A juvenile chiffchaff

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