The Willow Warbler looks very much like a Chiffchaff – they can be a bit tricky to tell apart at times, and are closely related species, but their songs are completely and utterly different.
Whereas the Chiffchaff’s song is simple and cuts through the early Spring air like a knife, the Willow Warbler has a complex liquid song which fills the air with melody and almost seems to cling to the vegetation as though golden treacle had been poured over the landscape.
I would expect, in normal times, to have heard a Willow Warbler by now, but I’ve never heard one from my garden and although it isn’t impossible that one could turn up, sing for a day, and move on, I won’t hold my breath.
And Willow Warblers don’t hold their breath either – here are some outpourings of Willow Warbler song, the first from the Netherlands:
And this one from Poland:
And this one from the UK where the sonogram shows very well the cascading nature of the song:
Aren’t they just wonderful? I hope I’ll hear one fairly soon but they are rarer than they used to be in southern England, but doing fine further north. I remember in 2015 when travelling around Scotland with a 6-foot Hen Harrier called Henry that every time we stopped and I got out of the car I would say ‘Willow Warbler!’ because there’d be one singing nearby, or several. Henry didn’t seem to pay them much attention at the time…