The chiffchaff and the willow warbler both members of the warbler or ‘Sylviidae‘ family. There are 63 members of the Sylviidae of which 14 species breed in the UK. They’re very similar to look at and can be pretty tricky to tell apart. Last week in my local meadow I came across both species in photographable locations so I thought I’d try to show the differences. Both species are summer migrants to the UK having overwintered in Africa, the chiffchaff goes to the Mediterranean and some head south of the Sahara, and the willow warblers all go down to tropical sub-Saharan Africa.
This publication from Birdlife International tells us that the global population of willow warblers is estimated to be between 300 million and 1.2 billion individuals, and a fact that blew my socks off was that the northern Siberian population overwinters in southern Africa, which is a journey of over 7000 miles or 11000 km… and back! And they’re only 19cm long and weigh 10g, so they may be tiny, but they’re incredibly tough. The chiffchaff is also a scarce winter visitor to the UK.
The willow warbler has longer primaries and the light stripe over the eye, the ‘supercilium‘ is brighter and more pronounced than that of the chiffchaff, and the ear coverts of the willow warbler (the patch under the eye) are a pale olive colour. The other visual diagnostic feature which is probably easiest to see at a glance is the leg colour, the willow warbler has pinkish brown legs whilst those of the chiffchaff are much darker, almost black.
The conservation status of the chiffchaff is green and in 2000 there were around three quarters of a million territories in the UK, but the willow warbler is amber due to a decline in the breeding population, but despite that there were still two milion territories in 2000.