Ceratina cyanea

BWARS describes it as the only example in Britain of a small carpenter bee.

In Britain it is widely distributed and locally common in south-east England, especially in the Weald.

Its habitats include south-facing chalk escarpments, heathland, disused sand quarries and open rides in deciduous woodland.

It has a single brood a year and flies from May to late August, although adults can be found in every month of the year.

From late summer onwards, adults of both sexes look for hollow stems in which to spend the winter.

The bees enter their winter burrows head first and stay inside, often in small groups, until the following spring.

A study of four European small carpenter bees found that individuals of this species mostly overwintered alone rather than in groups.

In the same study, some females of every species examined, including this one, tried to overwinter for a second time.

Females dig their nest burrows in dead, dry, broken woody or herbaceous stems where the soft pith has been exposed.

Most nests have been found in bramble stems, with a few in rose.

Inside the stem, the brood cells are separated by upright walls made of compacted fine wood dust.

It visits many flowers, including bulbous buttercup, bramble, tormentil, burnet rose, viper's-bugloss, heath, germander speedwell, thyme, wild basil, self-heal, harebell and rough hawkbit.

It was considered a great rarity in Britain until 1972, when it was found in abundance on a downland site in east Hampshire.

British Red Data Book reviews in 1987 and 1991 listed it as Rare (RDB3), and more recent records suggest it may be regarded as scarce.