Alert Status:
Red -81% decline
Estimated number of breeding males: 6,500
Listen to Wood Warbler song:
Wood warblers are one of the largest leaf warblers in the UK, with olive-green upperparts and heads with black tips on the wing and tail feathers. They have bright yellow flanks and breasts which stand out against their white bellies. They have yellow bibs and cheeks and a yellow eyebrow stripe (or supercilium). It is larger than the similar-looking willow warbler and chiffchaff and these birds all have very different songs.
Average Length: 12-13 cm
Maximum Known Lifespan: 6 years.
Average Wingspan: 19.5 - 24 cm
Wood warblers primarily eat invertebrates such as flies, beetles, and spiders and forage from the forest floor to the tops of the trees. They will also eat berries and fruit when invertebrate numbers decline.
Wood Warblers begin breeding in May when the female chooses a suitable nesting site and builds a dome-shaped nest on or close to the ground, hidden amongst scrub and dense vegetation. 5-6 eggs are laid in the nest and incubated for 12-13 days by the female and once hatched they are fed by both parents for 12-13 days. They usually only produce one brood before the breeding season ends in July so they can spend time feeding up before their migration.
The reasons for the long-term declines in wood warbler numbers are not well understood at all. Generic factors that impact similar birds such as droughts and habitat changes in the wintering grounds and loss of invertebrate prey due to increased pesticide use could be key drivers. While the loss of oak woodlands and reduction in oak health are thought to be important drivers of decline, little evidence has been found to support this. Changing management of oak woodlands over recent decades has been found to impact the populations of this species. This includes the loss of dead wood within the forest, loss of low-level vegetation, and loss of surrounding woodland.
Create an insect-friendly garden by avoiding harsh chemicals and allowing areas to grow long.
Be careful not to disturb active nests when walking in western woodlands.
Petition local areas to protect Oak woodlands.
The wood warbler, pied flycatcher, and redstart are often known as the “western oakwood trio” due to their habitat preference.
Awa Ii, T., Evaristus, T. A., Whytock, R. C., Guilain, T., & Mallord, J. (2018). Ostrich Journal of African Ornithology Habitat characteristics of wintering Wood Warbler Phylloscopus sibilatrix in the Centre Region of Cameroon: conservation implications. Ostrich, 89(1), 19–24. https://doi.org/10.2989/00306525.2017.1368037
BirdLife International (2023) Species factsheet: Phylloscopus sibilatrix. Downloaded from http://datazone.birdlife.org/species/factsheet/wood-warbler-phylloscopus-sibilatrix. Accessed: 16/10/2023.
British Trust for Ornithology (2023) Wood warbler | BTO - British trust for ornithology. Available at: https://www.bto.org/understanding-birds/birdfacts/wood-warbler. Accessed: 16/10/2023.
Huber, N., Kéry, M., & Pasinelli, G. (2017). Occupancy dynamics of the Wood Warbler Phylloscopus sibilatrix assessed with habitat and remote sensing data. Ibis, 159(3), 623–637. https://doi.org/10.1111/IBI.12472
Mallord, J. W., Charman, E. C., Cristinacce, A., & Orsman, C. J. (2012). Habitat associations of Wood Warblers Phylloscopus sibilatrix breeding in Welsh oakwoods. Bird Study, 59(4), 403–415. https://doi.org/10.1080/00063657.2012.727780
Mallord, J. W., Orsman, C. J., Cristinacce, A., Butcher, N., Stowe, T. J., & Charman, E. C. (2012). Mortality of Wood Warbler Phylloscopus sibilatrix nests in Welsh Oakwoods: Predation rates and the identification of nest predators using miniature nest cameras. Bird Study, 59(3), 286–295. https://doi.org/10.1080/00063657.2012.669359
Weisshaupt, N., & Rodríguez-Pérez, J. (2017). Bird Study Habitat use of the Wood Warbler Phylloscopus sibilatrix during spring migration versus breeding season based on citizen science data. https://doi.org/10.1080/00063657.2017.1364696
Woodward,I., Aebischer, N., Burnell, D., Eaton, M., Frost, T., Hall, C., Stroud, D.A.& Noble, D. (2020). Population estimates of birds in Great Britain and theUnited Kingdom. British Birds. 113: 69–104. https://britishbirds.co.uk
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