Common Chiffchaff
Phylloscopus collybita
The common chiffchaff is a small, dumpy, 10–12 centimetres (3.9–4.7 inches) long leaf warbler. The male weighs 7–8 grammes (0.28–0.31 oz), and the female 6–7 grammes (0.25–0.28 oz). The spring adult of the western nominate subspecies P. c. collybita has brown-washed dull green upperparts, off-white underparts becoming yellowish on the flanks, and a short whitish supercilium. It has dark legs, a fine dark bill, and short primary projection (extension of the flight feathers beyond the folded wing).
ID text from Wikipedia, CC BY-SA 4.0

Willow Warbler
Phylloscopus trochilus
The willow warbler is a typical leaf warbler in appearance, 11–12.5 cm (4.3–4.9 in) long and 7–15 g (0.25–0.53 oz) weight. It is greenish brown above and off-white to yellowish below; the wings are plain greenish-brown with no wingbars. Juveniles are yellower below than adults. It is very similar to the chiffchaff, but non-singing birds can be distinguished from that species by their paler pinkish-yellow legs (dark brown to blackish in chiffchaff), longer paler bill, more elegant shape and longer primary projection (wingtip).
ID text from Wikipedia, CC BY-SA 4.0

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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Common Chiffchaff and Willow Warbler.