Treecreepers are small and have mottled brown upperparts and heads with some light streaking and a white eyebrow stripe. They have white underparts and throat and a long downcurved bill. Their tail is often pressed against the tree they are climbing.
Average Length: 12.5 cm
Average Lifespan: 2 Years
Average Wingspan: 18-21 cm
Treecreepers mainly eat insects and spiders which they find in the bark of trees but will supplement their diet with seeds in winter when invertebrate numbers are low.
Breeding begins in late March when monogamous pairs team up to build a nest in a crack in the bark or a crevice behind the bark up to 16m above the ground. 5 to 6 eggs are laid in the nest and are incubated by the female for 13 to 16 days. Once hatched the chicks are fed by both parents for 14-16 days until the chicks fledge and for a few days after the chicks will return to the nest every few days to be fed by the parents. Treecreepers will produce a second brood before the breeding season ends in June.
While treecreepers are green-listed population declines in Europe may give an insight into future declines in the UK. Treecreepers rely heavily on mature trees full of cracks and crevices in which they can find insects. While fluctuations are common due to changes in food availability, European populations have declined due to habitat fragmentation and changes in forestry practices leading to the loss of mature trees. They are very susceptible to severe winter weather especially frost, which may make increasingly unpredictable weather damaging to the population. The continuing use of pesticides may also drive reductions in available food for this species.
Petition to protect old-growth woodland in the UK.
Avoid using harsh chemicals in your garden and petition local areas to avoid using chemicals in parks.
Treecreepers are home birds and stay within their small territories, most moving no more than 20km in their life and some sticking to a single tree!
BirdLife International (2023) Species factsheet: Certhia familiaris. Downloaded from http://datazone.birdlife.org/species/factsheet/eurasian-treecreeper-certhia-familiaris. Accessed: 09/10/2023.
British Trust for Ornithology (2023) Treecreeper, BTO. Available at: https://www.bto.org/understanding-birds/birdfacts/treecreeper. Accessed: 09/10/2023.
Huhta, E., Aho, T., Jäntti, A., Suorsa, P., Kuitunen, M., Nikula, A., & Hakkarainen, H. (2004). Forest Fragmentation Increases Nest Predation in the Eurasian Treecreeper. Conservation Biology, 18(1), 148–155. https://doi.org/10.1111/J.1523-1739.2004.00270.X
Suorsa, P., Helle, H., Koivunen, V., Huhta, E., Nikula, A., & Hakkarainen, H. (2004). Effects of forest patch size on physiological stress and immunocompetence in an area-sensitive passerine, the Eurasian treecreeper (Certhia familiaris): An experiment. Proceedings of the Royal Society B: Biological Sciences, 271(1537): 435–440. https://doi.org/10.1098/RSPB.2003.2620
RSPB (2023) Treecreeper bird facts: Certhia Familiaris, The RSPB. Available at: https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/treecreeper/. Accessed: 09/10/2023.