#treecreepers

I have made this bird spin

Short-toed Treecreeper - Trepadeira-comum (Certhia brachydactyla)

Cruz Quebrada/Portugal (7/09/2025)

Photo: Tom Murray

"Looking like a piece of bark come to life, the Brown Creeper crawls up trunks of trees, ferreting out insect eggs and other morsels missed by more active birds. It is easily overlooked until its thin, reedy call gives it away. Reaching the top of one tree, it flutters down to the base of another to begin spiraling up again. Creepers even place their nests against tree trunks, tucked under loose slabs of bark, where they are very difficult to find."

A short-toed treecreeper (Certhia brachydactyla) in Spain

Charley Harper (1922-2007)

Creeping up on the Eurasian Treecreeper

requested by @crazychooklady

The eurasian treecreeper (Certhia familiaris), as its name implies, is a species of tree creeper found throughout both Europe and Asia, in deciduous and evergreen forests. There are between 9 and 13 subspecies distributed across the continents, each with slight variations on the same morphology: 12 to 15 cm long, with a 19 cm wingspan and a weight of only 10g. The head, back, wings, and tail are typically mottled brown and the underbelly is a fluffy white.

The most distinguishing feature of any eurasian treecreeper is its bill, which is long, thing, and slightly curved. This makes it an excellent tool to search under tree bark for their main food source: insects. In addition, their tail feathers are especially stiff to support them as they climb vertically up tree trunks to forage. C. familiaris has few predators, due to their arboreal lifestyle and the excellent camouflage their colouring provides. Their main threats come from great spotted woodpeckers (Dendrocopos major), least weasals (Mustela nivalis), and stoats (Mustela erminea), all of which will feed on eggs and hatchlings.

Like many passerine birds, the eurasian treecreeper is monogamous. The breeding season occurs between March and June, when food is most abundant. Males sing to attract a mate, and once a pair has formed they build a nest in the crevice of a tree. The pair will lay two clutches over the course of the breeding season, each with 1-6 eggs that the female incubates. These eggs only take about two weeks to hatch, and another two weeks to fledge and become fully independent. During this time, both parents feed their young but males spend more time defending the nest. The young become sexually mature at only a year old, and individuals in the wild typically only live for about two years.

None of the C. familiaris subspecies are migratory. However, some share territories with another treecreeper species, the short-toed treecreeper (Certhia brachydactyla). The song of eurasian treecreepers that live in these areas differs from those of their relatives; their young learn the songs of both species, and thus sing mixed songs as adults. In addition, although they do not form flocks of their own, many eurasian treecreepers will join mixed species groups as extra protection against predators. 

Conservation status: The eurasian treecreeper is considered least concern by the IUCN, due to their large population and range. Habitat fragmentation and destruction for agricultural purposes are their largest threats, as they significantly increase predation risks.

Photos

Ryan Schaln (via eBird)

Dean Morley (via iNaturalist)