Acrocephalus arundinaceusgreat reed warbler(Also: great reed-warbler)

Geographic Range

Great reed warblers are migratory. Beginning in April and through the summer months, great reed warblers are found in northern Europe, especially the southern central region of Sweden. During the rest of the year, they migrate to the tropical regions of western Africa. ("Great Reed Warbler", 2002; Hansson, et al., 2004)


Great reed warblers are typically found near water, swamps and streams, in reed beds and other vegetation. ("Great Reed Warbler", 2002)

  • Aquatic Biomes
  • lakes and ponds
  • Range elevation
    200 to 700 m
    656.17 to 2296.59 ft

Physical Description

Great reed warblers are one of the larger warblers with masses of 21 to 51 grams and a typical length of 20 centimeters. The wings are long and rather pointed at the end. They have a brown color above and a whiter shade on the underbelly. ("Great Reed Warbler", 2002)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    21 to 51 g
    0.74 to 1.80 oz
  • Range length
    19 to 20 cm
    7.48 to 7.87 in
  • Average wingspan
    26 cm
    10.24 in


Many male great reed warblers are monogamous and polygynous. Females choose their mate partially on the quality of their territory, males with high quality territories tend to be polygynous. Females tend to choose territories in accordance with food abundance and based on nest site quality. Attractive territories also have less risk of nest predation. Males with lower quality nesting territories are monogamous or fail to mate. Polygynous males provide less parental care. Males also warn females by giving alarm calls when predators approach.Females also choose mates based on their song repertoire, which predicts reproductive success. Hasselquist et al. (1996) noted that females copulate with males other than their first mate only when that male has a greater song repertoire, resulting in extra-pair copulations. By engaging in extra-pair copulation, females are seeking benefits for their offspring since the fledgling survival is positively related to the father's song repertoire size. (Hansson, et al., 2000; Hasselquist, et al., 1996; Nowicki, et al., 2000)

Great reed warblers breed from early April through August in northern Europe and during the winter in parts of Africa. An average of three to six eggs per season are laid. Nestlings hatch after 14 days of incubation. Great reed warblers mate in reed beds of marshes and lakes. (Hansson, et al., 2004)

  • Breeding interval
    Great reed warblers breed seasonally, number of clutches attempted per breeding season is not reported.
  • Breeding season
    Breeding occurs from April to early August in Europe and in the winter in parts of Africa.
  • Range eggs per season
    3 to 6
  • Average time to hatching
    14 days
  • Average fledging age
    9 days
  • Average time to independence
    2 weeks

Females are responsible for building the nest and provide most of the parental care. The main contribution from the males is in protection of the nesting area from predators. Polygynous males help provide food for the offspring only for his first mate. Secondary mates must provide for their offspring on their own. Monogamous males provide food for the offspring. (Hansson, et al., 2000)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female


Little information is available on the lifespan of great reed warblers. They may live an average of 2.4 years in the wild.

  • Average lifespan
    Status: wild
    2.4 years


Great reed warblers are migratory, moving seasonally between Europe in the summer and sub-Saharan Africa in the winter. They are active during the day. ("Great Reed Warbler", 2002; Hansson, et al., 2004)

Home Range

Home range size is not reported in the literature.

Communication and Perception

Males sing songs of two varieties, one for attraction of females and the other for defending their territory. The mate attraction song lasts around four seconds. The territorial defense call is about one second in length. With these short territorial defense calls they are able to warn off other males without interrupting their other calls. (Price, 2008)

Food Habits

Great reed warblers have a varied, mainly carnivorous diet. They usually eat insects and spiders. Some fruits are eaten in the non-breeding season. They have also been observed eating snails, small fish, and frogs. Male warblers bring food to nesting females. ("Great Reed Warbler", 2002)

  • Animal Foods
  • amphibians
  • fish
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • Plant Foods
  • fruit


Great reed warblers emit alarm calls when they detect predators, such as marsh harriers. Bitterns and water rails are predators of eggs and nestlings. Other predators are not known. Great reed warblers are vigilant against predators and their cryptic coloration may help avoid predation. (Hansson, et al., 2000)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Great reed warblers impact their ecosystem by dispersing seeds and eating insects. Their nests are sometimes parasitized by common cuckoos (Cuculus canorus). They are susceptible to plasmodium infection. (Zehtindjiev, et al., 2008)

  • Ecosystem Impact
  • disperses seeds
  • creates habitat
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Great reed warblers are appreciated by bird enthusiasts for their songs and mimicry.

Economic Importance for Humans: Negative

There are no known adverse effects of great reed warblers on humans.

Conservation Status

Assessed in 2008, IUCN classifies great reed warblers as "least concern." The IUCN estimates a population size of 2,900,000 to 5,700,000 individuals. ("Acrocephalus arundinaceus", 2008)


Emily Bachert (author), Centre College, Rachel Gunn (author), Centre College, Stephanie Fabritius (editor, instructor), Centre College, Tanya Dewey (author), Animal Diversity Web.



living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map


living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map


uses sound to communicate


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

  1. active during the day, 2. lasting for one day.

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


An animal that eats mainly insects or spiders.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


marshes are wetland areas often dominated by grasses and reeds.


makes seasonal movements between breeding and wintering grounds


Having one mate at a time.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


having more than one female as a mate at one time


Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


uses sight to communicate


2008. "Acrocephalus arundinaceus" (On-line). The IUCN Red List of Threatened Species. Accessed April 08, 2009 at

Gale Group. 2002. Great Reed Warbler. Pp. 17 in M Hutchins, J Jackson, W Bock, D Olendorf, eds. Grizmek's Animal Life Encyclopedia, Vol. 11/4, 2 Edition. Farmington Hills, MI: Gale Group.

Hansson, B., S. Bensch, D. Hasselquist. 2004. Lifetime fitnes of short- and long-distance dispersing great reed warblers. Evolution, 58/11: 2546-2557. Accessed May 07, 2009 at

Hansson, B., S. Bensch, D. Hasselquist. 2000. Patterns of Nest Predation Contribute to Polygyny in the Great Reed Warbler. Ecology, Vol. 81, No. 2: 319-328. Accessed March 30, 2009 at

Hasselquist, D., S. Bensch. 2008. Daily energy expenditure of singing great reed warblers Acrocephalus arundinaceus. Journal of Avian Biology, Vol. 39/Issue 4: 384-388. Accessed April 10, 2009 at

Hasselquist, D., S. Bensch, T. von Schantz. 1996. Correlation between male song repertoire, exptra-pair paternity and offspring survival in the great reed warbler. Nature, 381: 229-232.

Nowicki, S., D. Hasselquist, S. Bensch, S. Peters. 2000. Nestling Growth and song repertoire size in great reed warblers: evidence for song learning as an indicator mechanism in mate choice. Proceedings of the Royal Society, B., 267: 2419-2424.

Price, T. 2008. Speciation in Birds. Greenwood Village, CO: Roberts & Company.

Zehtindjiev, P., M. Ilieva, H. Westerdahl, B. Hansson, G. Valkiunas, S. Bensch. 2008. Dynamics of parasitemia of malaria parasites in a naturally and experimentally infected migratory songbird, the great reed warbler Acrocephalus arundinaceus. Experimental Parasitology, 119/1: "99-110". Accessed March 31, 2009 at