Data Zone
Justification of Red List category
This species has an extremely large range and the population size is extremely large, hence does not approach threatened thresholds for the range or population size criteria. Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion. For these reasons the species is evaluated as Least Concern.
Population justification
In Europe, the total population size is estimated at 23,200,000-38,900,000 mature individuals, with 11,600,000-19,500,000 breeding pairs (BirdLife International 2021), and comprises approximately 80% of the species' global range, so a very preliminary estimate of the global population size is between 29,000,000-48,600,000 mature individuals, although further validation of this estimate is desirable. The species' population in Europe is considered to have undergone a small decline over three generations (12.39 years) (BirdLife International 2021). This species is considered to have a medium dependency on forest habitat, which is estimated to be declining at a slow rate within its mapped range (Global Forest Watch 2024). Accordingly the global population size is considered to be decreasing slowly over three generations.
Trend justification
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During the breeding season it inhabits dense bushes, woodland fringes and riparian forest with abundant undergrowth. It favours shady zones with herbaceous vegetation and broadleaf scrub and also often bushes close to reedbeds. In the Alps it occurs in stands of green alder (Alnus viridis) and birch (Betula) and various willows (Salix). In central Europe it prefers the presence of hawthorn (Crataegus monogyna) and blackthorn (Prunus spinosa), and in Finland is associated with raspberry (Rubus idaeus). In Britain it is abundant in areas of sessile oak (Quercus petraea). In its African non-breeding range it uses woods, forest edge, orchards and gardens, sometimes entering forest when fruits are available. It also occupies savanna and dry zones with dense thicket vegetation, e.g. acacia (Acacia) and brachystegia (Brachystegia) woodlands. It avoids closed forest, but can enter open montane forest at up to 2,600 m, although it prefers lower altitudes. Breeding occurs from April to July. The nest is a cup constructed from plant material such as grass, leaves and roots and lined with fine grass and hairs. It is usually placed low down, hidden in tree or bush or among tall plants. Clutches are four or five eggs. The diet is mostly insects throughout the year, especially during the breeding season, when some fruits and plant material are also taken. Through the rest of the year it is mostly frugivorous. The species is a long-distance migrant (Aymí and Gargallo 2015).
The spread of exotic Reynoutria spp. has been shown to reduce numbers of this species where it occurs (Hajzlerová and Reif 2014). Alterations or fragmentation of important refuelling habitats south of the Sahara could reduce survival (Aymí and Gargallo 2015).
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
In areas where it is a problem, management actions should be developed that counter-act the invasion of Reynoutria spp. (Hajzlerová and Reif 2014).
Text account compilers
Rutherford, C.A., Martin, R.
Contributors
Dowsett, R.J.
Recommended citation
BirdLife International (2024) Species factsheet: Garden Warbler Sylvia borin. Downloaded from
https://datazone.birdlife.org/species/factsheet/garden-warbler-sylvia-borin on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.