Acrocephalus scirpaceus
A wetland songbird with a rather unremarkable appearance, the reed warbler is a spring visitor to the UK, raising young in wetland reedbeds across England and Wales before returning to African wintering grounds at the end of the summer.
Reed Warbler
Juvenile Reed Warbler
Reed Warbler chattering
Portrait of a Reed Warbler
Both male and female reed warblers have sandy-brown upperparts, a light buff lower breast and belly, and a whitish chin and throat. Facial markings are subtle, with a pale eyestripe sometimes visible, and a faint whitish eye ring.
The bill is brownish-grey and narrow: well-suited for their seed-based diet. Their legs are dark grey, which helps to distinguish them from the similar marsh warbler, which has flesh-coloured legs.
From a distance, juvenile reed warblers are similar to adults, but on closer inspection, young birds can be told apart by their warmer brown plumage and more intense buff colouring on their underparts and flanks.
Reed Warbler in natural habitat
Reed warblers are small warblers, roughly the same size as a robin or a house sparrow, but with a slimmer shape. There is no size difference between males and females.
Reed Warbler perching on a thin branch
A reed warbler’s song is often a more accurate way of verifying their identity than relying on a visual ID, as they sing from deep inside reedbeds and are extremely hard to spot.
Their song is rhythmic and flowing and consists of alternating chattering and grating phrases, which are then repeated. Some mimicry of other species and sounds may also be heard. In alarm or distress, a sharp ‘tsche’ call is uttered.
Reed Warbler in song
Reed warblers are mainly insectivorous, feeding on small beetles, flies, caterpillars, moths, and insect larvae. They pick prey off the stems and blades of reeds, and tiny spiders and snails may also be caught. In autumn, their diet may occasionally include berries, including currants, elder, cherry and dogwood. Termites, aphids, and mosquitoes are eaten on wintering grounds.
Feeding reed warbler chicks is a demanding task, with both parents bringing tiny insects and spiders to the nest several times each hour.
Reed Warbler feeding on a grub
Waterside reedbed environments are required for breeding and are mostly found around the fringes of lakes and ponds, on riverbanks and in ditches. In certain parts of eastern and southern Africa, nests may be built in mangroves.
In winter, reedbeds are not as vital, and reed warblers can be frequently found on scrubland and thickets of papyrus, grass, and bamboo, as well as in mangrove forests.
Reed warblers are found across Europe, from the UK and Scandinavia in the north, as far south as the Mediterranean. Their range extends to North Africa, where a few coastal locations in Morocco, Algeria, and Tunisia have small year-round populations. In the east, breeding grounds reach Central Asia, with Russia, Kazakhstan, and parts of Iran, Turkmenistan and Uzbekistan.
Across much of North Africa, the Middle East, and southern Europe, reed warblers are seen in migration passage only as they travel to and from their wintering grounds in sub-Saharan Africa. Some migrants reach as far south as South Africa, where there are also populations of resident reed warblers.
Europe’s reed warblers make up around 35 percent of the global population. The largest numbers of these are believed to be in Romania, Sweden and Germany.
While reed warblers are fairly widespread, sightings are quite uncommon due to their preference to remain hidden out of sight in dense reedbeds. There are 130,000 breeding territories in the UK and a total of between 2.12 and 3.88 million pairs in Europe.
Any reedbed environment, even those with just a few simple strands of reeds and rushes, attracts reed warblers in spring and summer, and they can be found in the largest concentrations across southern England, particularly East Anglia and along the south coast. In recent years, breeding has spread to parts of Scotland.
Reed Warbler resting on grass stem
Two years is the average lifespan for a reed warbler, with first-time breeding at one year old. Occasionally, much older birds may be recorded via ringing schemes, including one individual that reached 12 years and 11 months.
Reed warblers are particularly vulnerable to avian predators that share their habitats, such as little bitterns and grey herons. Cuckoos are also a key factor in brood failures, as they remove reed warblers’ eggs and replace them with their own. Mice and rats may also raid nests for eggs and young nestlings.
Reed warblers are included in the Wildlife and Countryside Act, 1981, which offers the species protection from being knowingly killed, injured, or taken into captivity. Although no current wider protection of habitats is in place, reed warblers would benefit from conservation measures to preserve wetlands.
Overall, the global, European, and UK populations of reed warblers are stable, and they are classified as a species of least concern. In the UK they have Green status on the British Birds of Conservation Concern list and increases have been recorded in recent years, and there are no immediate threats to their long-term future. However, wetland destruction and reclamation of marshlands have impacted some local populations.
Reed Warbler feeding a common cuckoo at the nest
Waterside locations, hidden from sight in dense reedbeds or aquatic grasses, offer ideal spots for nesting reed warblers to build their cup-shaped nests.
Nests, which are cylindrical and neatly woven out of reeds, grasses, leaves, and other plant matter are tethered in place on the stems of reeds, with the female doing most or all of the construction.
Male reed warblers arrive on breeding grounds ahead of females, from April onwards, and breeding begins in late April or early May. Raising more than one brood in a season is not uncommon, and nesting can last until early August.
Incubation is shared between males and females, and takes 12 days, with young reed warblers fledging at between 11 and 12 days old.
Reed warbler eggs have a pale greenish-white base colour and are marked heavily with dark grey spotting around one end. Four to five eggs are laid, measuring 18 mm by 14 mm (7.1 in by 5.5 in).
Reed warbler pair bonds last for a single breeding season and dissolve once their final brood has fledged. The following year, they usually mate with a different partner.
Nest of a Reed Warbler
Reed Warbler feeding young at the nest
While reed warblers are not a particularly aggressive or threatening species, they do exhibit territorial behaviour during the breeding season.
Their nests are frequently used as hosts for cuckoos, and reed warblers have a heightened sense of vigilance, warning other nearby reed warblers with a loud and repetitive alarm call when a cuckoo’s presence is detected nearby.
Reed Warbler taking-off from the bushes
Reed warblers that breed in Europe are migratory, heading south to central and southern Africa once they have finished raising their young on wetlands across Europe and Central Asia. Sub-Saharan Africa is their winter destination, where they overlap with a subpopulation of African reed warblers that are year-round residents in the south of the continent.
Reed warblers are breeding visitors to the UK, arriving in April each year and leaving later in the summer, with all birds having departed by the end of September. No reed warblers are resident in Britain all year round, spending colder months in Africa, south of the Sahara.
Scientific name:
Acrocephalus scirpaceus
Other names:
Common Reed Warbler
Family:
WarblersConservation status:
Green
Length:
13cm to 14cm
Wingspan:
17cm to 21cm
Weight:
10g to 15g
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