1. The treecreeper has many regional names: the Somerset name, tree mouse, is perhaps most appropriate, as this bird does creep up trees in a mouse-like manner.

2. Treecreepers always go up trees, never down. When they get to the top they fly to the bottom of the next tree.

3. Though they favour woodland, they will often wander into orchards and gardens.

4. They are almost entirely insectivorous, with spiders and other small insects forming the bulk of their diet. In winter they make take some small seeds.

5. In the UK they have rarely been recorded visiting feeding stations. However, the American treecreeper (a very close relation of our bird) will visit feeders for suet.

6. The beak is ideally adapted for finding insects in the crevices of tree bark: it is very slender, slightly decurved and sharply pointed.

7. The tail is an invaluable aid to the bird’s tree climbing. The 12 tail feathers are stiffened with robust shafts that project at the tip.

8. Widely distributed throughout the British Isles, they are only absent from areas where there are no trees, such as the Fens, the Outer Hebrides and tops of mountains.

9. A second species of treecreeper, the short-toed, replaces our bird throughout much of lowland Europe. It has been recorded in southern England on a number of occasions, but is very rare here.

10. Visually very similar to our treecreeper, the short-toed is best identified by its distinctive song, which is louder and more tit-like.

11. The only treecreeper to occur in the Channel Islands is the short-toed, where it is common on Jersey and Guernsey.

12. In total there are nine similar species of treecreepers found in the world. Our bird, Certhia familiaris, is the most widely distributed and can be found as far east as Japan.

13. The treecreeper with the smallest range is the Sichuan, restricted to the west Sichuan mountains in China.

14. Nests are usually built between the trunk of a tree and a piece of loose bark, but these birds will readily adopt suitable nestboxes.

15. The nest itself is an untidy collection of twigs, pine needles, moss and wood chips, lined with feathers, hair and even spiders’ webs.

16. The usual clutch is five or six white eggs with fine red spotting. Only the female incubates the eggs.

17. Both sexes feed the young, which leave the nest between 14 and 21 days after hatching. They remain dependent on their parents for another 11 to 17 days.

18. In the British Isles most pairs only attempt to raise one brood, but a second brood is not unusual.

19. After breeding treecreepers often join tit flocks, with which they will remain throughout the winter.

20. Our birds seldom move far from where they hatched, but northern populations migrate south in the winter.

21. The treecreeper is one bird that has apparently increased in the British Isles in recent years.