Common chiffchaff one of the first avian signs that spring has returned. Its call is a "hweet", less disyllabic than the "hooeet" of the willow warbler or "hu-it" of the western Bonelli's warbler. The song differs from that of the Iberian chiffchaff, which has a shorter . However, mixed singers occur in the hybridisation zone and elsewhere, and can be difficult to allocate to species. When not singing, the common chiffchaff can be difficult to distinguish from other leaf warblers with greenish upperparts and whitish underparts, particularly the willow warbler. However, that species has a longer primary projection, a sleeker, brighter appearance
The Birds' Christmas Carol illness (possibly tuberculosis), and, by the time she is 10, she is bedridden; physicians say that she does not have long to live. Most of the brief novel's plot involves Carol making plans for a Christmas celebration for the nine Ruggles children, a poor, working-class family living near the Birds. Wiggin's story is primarily a moral tale about a saintly child, but unlike many other such stories of the period, Carol is refreshingly intelligent and cheerful instead of pious. The story is also enlivened by many humorous touches, particularly in the scenes of the Ruggles family's home life. In 1917,