Locustella naevia is a fairly widespread summer visitor to much of Europe, which constitutes >50% of its global breeding range. Its European breeding population is large (>840,000 pairs), and was stable between 1970-1990. Although there were declines in a number of countries during 1990-2000, the sizeable population in Poland was stable, and the species increased or was stable elsewhere. The trend of the stronghold population in Russia was unknown, but the species probably remained stable overall.

In middle, mainly temperate, latitudes of west Palearctic. mostly continental but marginally oceanic. Generally in lowlands or on low hills. Avoids rocky and broken ground, human settlements and well-grown forests, and over much of range infrequently extends into cultivated areas or those with very low or sparse vegetation.

Breeds mid April to mid June in Britain and West Europe, May to mid July in South West Germany, April-May in Switzerland. Nest site is built on or just above ground in thick vegetation, often in tussock. Nest, thick cup of grass and plant stems and leaves, on base of dead leaves, lined with finer material, sometimes including feathers, horse hair, and plant down. 5-6 eggs are laid, incubation 12-15 days, by both parents.

Mainly insects. Food obtained while moving restlessly through vegetation and on ground. Rummages among dead leaves and stays long in one place dealing with prey once found. in reeds, carefully examines each stem from top to bottom, working through all leaf axillae and from time to time descending to prostrate stems to dig for insects among them. Also hovers to pick prey from leaves and sometimes takes insects in flight.

This species has a large range, with an estimated global Extent of Occurrence of 10,000,000 km². It has a large global population, including an estimated 1,700,000-4,400,000 individuals in Europe (BirdLife International in prep.). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Migratory. Winter quarters of west Palearctic birds not well known; apparently mainly in West Africa south of Sahara, with migration route concentrated through Iberian peninsula and along African west coast. Autumn passage chiefly August-September; prolonged spring passage February-May.

article number 1 Title
The study of bird migration across the Western Sahara; a contribution with sound luring
Author(s): Marc Herremans
Abstract: During spring and autumn migration 2003, the Swiss Ornithological Institute set up a concerted project in Mauritania to study bird migration across the Sahara. I participated with a side project using..[more]..
Source: Report of field research in Mauritania
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article number 2 Title
Grasshopper Warbler Locustella naevia autumn migration-findings from a study in southeast Britain
Author(s): Nicholas J. Bayly and Stephen J.R. Rumsey
Abstract: This study examines the migratory behaviour of Grasshopper Warblers Locustella naevia on the south coast of Britain with respect to phenology, fuel loads, stopover behaviour and potential flight range..[more]..
Source: Ringing & Migration (2007) 23, 147-155
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