Every spring our readers report the arrival in the park of a small grey green bird with a pale eyestripe and cream underparts. This is either a chiffchaff or a willow warbler and it’s very hard to tell the difference.
There have been many words written about the subtleties of eyestripes (the chiffchaff has a less distinct eyestripe) and the length of wing feathers (the willow warbler has longer primary feathers) but the only real visible difference is the colour of the legs. A willow warbler has pale pinkish legs and the chiffchaff has dark brown or black legs. Unfortunately neither sits still long enough for anybody to actually see the colour of its legs.
Sometimes, though, it is easy to tell the difference and this is why:
a willow warbler sings a small sweet melody;
Willow warbler recorded by Alexander Henderson in Sutton Park Birmingham
and a chiffchaff just shouts its name over and over.
Chiffchaff recorded by Andrew Harrop at Woodwalton Fen, Cambridgeshire
willow warbler – amber – since 1995 population has decreased by 66%
chiffchaff – green – population increasing.
Photographs of chiffchaff by DKG
This post was first published in April 2019.