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.
Willow warbler (Phylloscopus trochilus, Dansk: løvsanger) collecting nesting material
Willow warbler showing off her pink legs, bright supercilium and pale ear coverts
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.
Chiffchaff showing off its more subdued facial markings and overall colour scheme and the dark coloured legs
In the absence of a clear sighting the easiest way to differentiate between these two species is by their song: click here to hear the chiffchaff song, and here for the willow warbler song.
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.
The Naturephile 
Great post Finn! Living on the edge of a wooded area, we often hear birds that we seldom see. I was thinking, living in an area so rich in bird species, you must be treated to a constant serenaded of bird calls. When you are out in the field, do you ever just close your eyes and let the songs overtake you?
Hello Rick, when the weather is like it is now (sunny, warm, calm) there is alot of birdsong. I was in my local meadow this evening and I thought of your comment as there were swifts screeching up high, rooks cawing a little lower down, and dunnock, house sparrows, green woodpeckers, chiffchaff and several others all singing away in the trees and bushes. And Tuesday night is special because it’s when the bellringers practice at the village church. So I was serenaded by lots of birds and the bells, so I sat on the ground and watched the sun lowering in the sky and just listened. Sensory overload – it was glorious!
Wonderful captures. We’re big birders in our family, and warblers are among the toughest to identify (at least for me). I’ve never had the pleasure of seeing either the chiffchaff or the willow warbler in real life. It’s a delight to be introduced to them here.
Warblers are tricky, and we have quite few, I think learning the song is probably the best way to tell them apart – but that’s pretty tricky too 🙂
I love the pictures of the willow warbler with the nesting materials, they are pretty little things, sort of ‘cleaner’ than the chiffchaff in the brighter breeding plumage.
They are more distinctive, but I do like the chirruping chiffchaff too.
A treasure trove of nature facts and shots all in one place! Thank you for this wonderful site! Sharon
Thanks Sharon – it’s a pleasure!
It’s very useful that their songs are quite different. Your photos are always great Finn, but I especially love the chiffchaffs.
Thanks Lorna, the chiffchaffs are rather lovely. Do you hear them round your way? Fortunately for me the trees and hedgerows are alive with them round here.
I wish I could tell you but I’m hopeless at identifying birds by their songs. It would be interesting to go on a field trip to learn more about it. Pity that wasn’t part of my ecology course. Jo Woolf mentioned chiffchaffs in a recent post and she’s not all that far away from me, so perhaps we do have them in Perthshire too.
My skills in that department are fairly poor too, but I’m putting some effort into learning them and the number of species I can now recognise is increasing. And it’s good fun trying.
I think chiffchaffs are found in Perthshire as summer visitors.
Ooops, I now realise my error. The above should have read 80.9% failure rate at egg stage. More appropriately, the 32% failure rate at chick stage still suggests my opinion is correct on the lack of insect prey affecting bird populations.
Best Wishes
Tony
The latest Bird Trends data also seems to back up your thoughts as well, Finn. For Chiffchaff, see here, http://blx1.bto.org/birdtrends/species.jsp?s=chiff and Willow Warbler, http://blx1.bto.org/birdtrends/species.jsp?s=wilwa
Indeed, those great migrations are amazing. However, it is particularly disturbing that upon arrival, many birds and especially the Willow Warbler it seems, struggle to raise their broods to fledgling status. Note, the 80.9% increase in nest failure rate! Simply put, these warblers and many farmland birds need more insect food.
Best Wishes
Tony
The lack of insects is a real issue and needs to addressed as a matter of urgency, not just for the birds, but the bees too. We need to protect the pollinators. Thanks for the links.
Pretty little guys! Great photos and interesting information!
I’m glad you like them Terry, they are pretty, and so hardy too.