By Andreas Trepte - Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=14979556
Sanger
Sources:
(*) https://en.wikipedia.org/wiki/Willow_warbler
(*) https://ebird.org/species/wlwwar
(*) https://search.macaulaylibrary.org/catalog?taxonCode=wlwwar