Justification of Red List category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
In Europe, the breeding population is estimated to number 916,000-1,620,000 pairs, which equates to 1,830,000-3,240,000 mature individuals (BirdLife International 2015). Europe forms c.60% of the global range, so a very preliminary estimate of the global population size is 3,050,000-5,400,000 mature individuals, although further validation of this estimate is needed.
In Europe the overall trend from 1980-2013 was stable (EBCC 2015).
This species breeds at the edges of open woodland, in damp grazing land, in rank grasses, beds of nettle (Urtica) and brambles (Rubus fruticosus), scrubby sedge or reed marshes, at field edges and on upland moorland with willow (Salix) and birch (Betula) scrub. Egg-laying occurs from late April to mid-July in western Europe and clutches are typically five to six eggs. The nest is a thick cup of grass, stems and leaves built on a base of dried leaves and lined with finer material, such as feathers or hair. It is usually placed on or near the ground in thick vegetation, often in a grass tussock, bramble or sedge. The diet is mostly insects but spiders (Araneae) and some small molluscs are also taken. The species is a long distance migrant, passing through the Iberian Peninsula to winter in West Africa (Pearson and Kirwan 2015). The obscurior race that breeds in the Caucasus probably winters in North-East Africa. The straminea race that breeds in Central Asia winters in southern Asia with large numbers spending the non-breeding season in India although some also migrate to North-East Africa. The mongolica race is presumed to winter in southern Asia (Pearson and Kirwan 2015).
This species suffers from changing land-use practices, such as the intensification of agriculture, leading to the destruction of grassland (Hagemeijer and Blair 1997), wetland drainage and scrub clearance (Hagemeijer and Blair 1997, Pearson and Kirwan 2015). The species is also likely to be affected by future climate change (Huntley et al. 2008).
Conservation Actions Underway
CMS Appendix II. Bern Convention Appendix II. There are currently no known conservation measures for this species within Europe.
Conservation Actions Proposed
This species would benefit from the preservation and promotion of low-intensity farming methods, which provide much suitable habitat (Hagemeijer and Blair 1997).
Text account compilers
Butchart, S., Ekstrom, J. & Symes, A.
BirdLife International (2023) Species factsheet: Locustella naevia. Downloaded from http://datazone.birdlife.org/species/factsheet/common-grasshopper-warbler-locustella-naevia on 01/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 01/10/2023.