February is a good time to trim straggly deciduous or mixed hedges and overgrown climbers. Beech hedges can also be renovated now. Get the work done as soon as possible before the start of the bird-nesting period.
To wilfully damage or destroy a nest of a wild bird while it is in use is an offence under the Wildlife and Countryside Act of 1981 (and its amendment by the Countryside and Rights of Way Act 2000). Even nests in the process of being built are protected by law.
The main nesting season usually runs from March to July. It is not illegal to trim garden hedges during this period, but great care must be taken if you suspect birds are using the hedge to nest in. If in any doubt, do not start trimming as even disturbance near the nest could upset the breeding process.