During the COVID Lockdowns we started to get more and more uncommon birds to the garden as traffic on the roads was less frequent. Although I am only 50% sure this is a Willow Warbler, the lighter coloured legs and the more distinct eye stripe are a good start for identifying a Willow Warbler instead of a Chiffchaff but they are not exact. The Ciffchaff is far more common in the garden as can be seen by the sightings of Chiffchaffs listed on my Chiffchaff – What Birds I Spotted Today year lists. The only way I know how to visually tell the difference is that the Chiffchaff has emargination on the sixth primary feather. There’s a small photo mine on 2018 Edinburgh, Scotland Garden Bird List. I will try to dig out the bigger version and add it here in the future to help others identifying the difference between a Willow Warbler and a Chiffchaff.
The great to add it to my what bird has spotted today garden list. www.wbist.com.