I designed these bird nesting cavities over 20 years ago and they really work well.
Though nesting cavities provide wild birds with nest sites in the early spring and summer, they are also critical in winter too. I recall one time when I checked one of my cavities finding 8 wrens in the same box. It was a hard winter’s night in December when the temperature was below zero for the 10th night running. Huddled together these birds looked like a solid mass of heads.
Placing nesting boxes at this time is important. Birds use them to over winter as winter housing on cold nights and it’s important that they locate them at this time, before the winter sets in. My cavities are round as the walls follow the round of the log. This takes much less nesting material to fill the cavity in nesting season, but there is nothing wrong with adding soft, warm nesting material for the winter time as this is not ritualistic courtship time. Simply remove the material prior to spring courtship time as nest building is critical to pairing off prior to and during mating with most cavity nesting birds and of course others too.
All our nesting boxes have removable or hinged lids for monitoring and clean-out.
We sell the nesting cavities for £19 plus shipping and handling. (For hinged lids instead of pegged as £3 more)