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 fluctuating, 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 6,050,000-11,400,000 pairs, which equates to 12,100,000-22,700,000 mature individuals (BirdLife International 2015). Europe forms c.30% of the global range, so a very preliminary estimate of the global population size is 40,000,000-76,000,000 mature individuals, although further validation of this estimate is needed.
Northern and eastern populations tend to fluctuate in an irregular pattern, possibly tied to variations in the crop of spruce seeds (Harrap 2015). In Europe, trends between 1980 and 2013 have been stable (EBCC 2015).
This species inhabits forest and woodland, generally requiring well-grown trees with many cracks and crevices in the bark for foraging, roosting and nesting. It tends to favour older stands of spruce (Picea), but habitat preferences are complex and apparently affected by presence or absence of Certhia brachydactyla. In the western Palearctic breeding occurs from late March to June. In Japan breeding takes place between May and July. The species is monogamous and both sexes build the nest from conifer needles, bark fibres, grass, moss, lichen, wood chips and the like and the lining, which is added by the female alone, includes feathers, hair, wool, lichen, spider webs, eggs and cocoons. It is placed up to 16 m above ground behind a flap of loose bark or in a crevice on a tree trunk, in a building or stone wall and occasionally hidden among or behind vegetation. Clutches are typically five or six eggs. The diet is mostly insects, spiders (Araneae) but also takes some seeds, particularly pine and spruce, in the winter. Western and southern populations are largely resident but more northerly populations tend to move south after breeding (Harrap 2015).
In Europe, populations may be exhibiting declines owing to habitat fragmentation and the loss of older-growth woodland (Harrap 2015) through modern forestry management practices (Hagemeijer and Blair 1997). The species is susceptible to the effects of severe winters, especially extended periods of glazed frost or freezing rain. In the north and east of its range populations fluctuate in an irregular pattern, which may be linked to variations in the crop of spruce seeds (Harrap 2015). The species may also suffer from the effects of future climate change (Felton et al. 2014).
Conservation Actions Underway
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 promotion and expansion of forest managed under low-intensity practices, particularly the preservation of older woodland growth.
Text account compilers
Butchart, S., Ashpole, J, Ekstrom, J.
BirdLife International (2017) Species factsheet: Certhia familiaris. Downloaded from http://www.birdlife.org on 22/10/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2017.