Sedge warblers have brown upperparts with some dark brown streaking, black wings with light brown edges to the feathers, a cinnamon-coloured rump and a dark brown tail. Their head is the same brown colour as their back, with a white stripe above their eye. Their underwing is a pale yellow colour and their breast and throat are white. Their song can be hard to identify due to their mimicry skills.
Average Length: 13 cm
Average Lifespan: 2 Years
Average Wingspan: 17-21 cm
Sedge warblers will primarily eat invertebrates such as moths, beetles and worms but they will supplement their diet with berries in autumn and winter. They will take berries and seeds from feeding tables and feeders.
The breeding season begins at the end of April or the beginning of May when around 5 eggs are laid in a deep cup-shaped nest woven from dry grasses, plant stems and leaves placed low over marshy ground. The female incubates these eggs for 2 weeks before they hatch, once hatched both the male and female will brood the chicks until they leave the nest 12-13 days later. Once they leave the nest they will be looked after by the parents until they fledge and become independent.
Sedge warbler populations fluctuate year to year, this is mainly driven by changes in rainfall in their overwintering sites. Climate-driven droughts or heavy rainfall decrease survival by reducing the supply of food available before their migration. Changes in their preferred wetland and waterside habitats in the UK through habitat loss and degradation are also likely to drive population declines.
Help your local area keep wetland and waterside habitats clean and in good shape.
These birds nest low to the ground so be careful if exploring wetland sites.
Provide ample food in autumn to help them fuel up before their migration.
Sedge warblers are great mimics and the male will introduce a range of phrases into his song, never singing the same song twice, in an attempt to impress the females.
BirdLife International (2023) Species factsheet: Acrocephalus schoenobaenus. Downloaded from http://datazone.birdlife.org/species/factsheet/sedge-warbler-acrocephalus-schoenobaenus. Accessed: 27/09/2023.
British trust for ornithology (2023) Sedge warbler | BTO - British trust for ornithology. Available at: https://www.bto.org/understanding-birds/birdfacts/sedge-warbler. Accessed: 27/09/2023.
Bayly, N. J. (2007). Extreme fattening by sedge warblers, Acrocephalus schoenobaenus, is not triggered by food availability alone. Animal Behaviour, 74(3), 471–479. https://doi.org/10.1016/j.anbehav.2006.11.030
Nicholson, J. S., Buchanan, K. L., Marshall, R. C., & Catchpole, C. K. (2007). Song sharing and repertoire size in the sedge warbler, Acrocephalus schoenobaenus: changes within and between years. Animal Behaviour, 74(5), 1585–1592. https://doi.org/10.1016/j.anbehav.2007.04.006
RSPB (2023) Sedge warbler bird facts: Acrocephalus Schoenobaenus, The RSPB. Available at: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/sedge-warbler/. Accessed: 27/09/2023.