The Reed Warbler, Acrocephalus scirpaceous, is one of the ‘Acro’ warblers’, with the typically low, sloping forehead and sharp bill. As its name suggests, it is most often found in reed beds and marshy areas. It has strong legs and feet for clinging on to reed stems. It spends time near the water and it’s useful to scan along the bottom of the reeds, looking out for any movement which may well be a Reed Warbler hunting for insects. It will also hunt in nearby Willows.
They are more likely to be heard before they are seen as they keep up a continuous, steady chatter which carries over a surprisingly long distance.
Its plumage is a plain, warm brown with no streaking, a white throat and pale underparts. In Guernsey, this migrant usually arrives around the third week of April, but a few individuals have been recorded in the island earlier in the month. It breeds in the island over the spring and summer, making a cup-shaped nest which is woven around a few reed stems.
The Reed Warbler is one species that is brood parasitised by the Cuckoo. A female Cuckoo will quickly lay her slightly bigger egg in the nest when both parents are absent. The egg closely resembles those of the Reed Warbler. When the young Cuckoo hatches, it will soon eject the other eggs or young birds from the nest. The Reed Warbler parents will continue to feed the Cuckoo, although it will grow to be considerably bigger then they are
Reed Warblers will choose a night in September to leave for their wintering grounds in sub-Saharan Africa.
Natural history of the Bailiwick of Guernsey 