The common grasshopper warbler or just grasshopper warbler (Locustella naevia) is a species of Old World warbler in the genus Locustella. It breeds across much of temperate Europe and the western Palearctic. It is migratory, wintering across northern tropical Africa just south of the Sahara, and also locally in India.

This small passerine bird is found in dense grassland vegetation, often close to water, and usually with a few small scattered shrubs. It is a medium-sized warbler about long. The adult has a streaked brown back and whitish grey underparts which are unstreaked except on the undertail coverts. The sexes are identical, as with most warblers, but young birds are yellower below. Like most warblers, it is insectivorous. Four to seven eggs are laid in a nest on or near the ground in thick vegetation or in a tussock of grass.

This is a species which skulks in the undergrowth, creeping through bushes and low foliage, and which is very difficult to see except when singing from a prominent position. The song, which gives this species its name, is a mechanical grasshopper-like reeling, often given at dawn or dusk.

Taxonomy

The Italian naturalist Ulisse Aldrovandi included the common grasshopper warbler in the second volume of his Ornithologiae. Aldrovandi died in 1605 but the volume was not published until 1637. In 1760 the French zoologist Mathurin Jacques Brisson included a detailed description of the common grasshopper warbler in his Ornithologie. He used the French name La fauvette tachetée and the Latin name Curruca naevia but although Brisson coined Latin names, these do not conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature.

Its first formal scientific description was by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1779 in his Histoire Naturelle des Oiseaux. The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Motacilla naevia in his catalogue of the Planches Enluminées; he used the word naevia that had earlier been used by Brisson.

The type locality is Bologna in Italy. The common grasshopper warbler is now one of 20 species placed in the genus Locustella that was described by the German naturalist Johann Jakob Kaup in 1829 with the common grasshopper warbler as the type species. The genus name Locustella is from Latin and is a diminutive of locusta, "grasshopper". The specific naevia is Latin for "spotted".

Three subspecies are recognised. It is a secretive bird and can be hard to see, but its presence is easily detected because of its characteristic song.

The song is a long, high-pitched reeling trill performed with beak held wide open and the whole body vibrating. It lasts from a few seconds to several minutes without any pauses, and is of remarkable speed and complexity, consisting of 52 notes (26 double notes) per second; its speed and high pitch however make it impossible for human ears to analyse without slowed-down recordings. It varies in volume from a sound resembling an angler's reel to a distant mowing machine. It is strongly ventriloqual, making it difficult to pinpoint the location of the singing bird, but has strong carrying power, audible at ranges of up to 500 m to even 1 km. The song can be heard at any time of day or night, but peaks around dawn and dusk, and can be heard from the arrival of the birds in April until early August. The alarm call is a repeated ticking noise that has been rendered as "twkit-twkit-twkit". The song shows similar 'reeling' structure to that of some of its congeners, notably lanceolated warbler (Locustella lanceolata), Savi's warbler (Locustella luscinioides) and river warbler (Locustella fluviatilis), though they are all distinguishable in different tones and speed.

Distribution and habitat

The common grasshopper warbler breeds in northwest Europe and the western Palearctic. The range includes Spain, France, central Italy, Romania, Yugoslavia, the British Isles, Belgium, Netherlands, Germany, Denmark, southern Sweden, southern Finland, the Baltic States and western parts of Russia. Further east it is replaced by related species. In autumn, it migrates south to the Sahel region of tropical Africa, India and Sri Lanka where it overwinters.

References

Further reading

  • Xeno-canto: audio recordings of the common grasshopper warbler