DKG photographed 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 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.
DKG is sure that he photographed a chiffchaff, though, and this is why:
a willow warbler sings a small sweet melody;
and a chiffchaff just shouts its name over and over.
willow warbler – amber – since 1995 in east and south east England, population decreased by 66%
chiffchaff – green – population increasing.