Nest Box Preparations

Clearing the box

I left it a bit late to clear the nest box after last season. The RSPB recommend the best time to clear a box is between September and January. I generally leave it until late October, when I can be sure that the birds have finished with their nest.

The September to January window is particularly important, and not just because it is likely to be outside the breeding season. It has been illegal to take any birds’ eggs from the wild in Great Britain since 1954. This includes eggs from bird boxes. However, General Licence says unhatched eggs remaining in the box may be removed between September and January, (August – January in Scotland). Under the terms of the Wildlife and Countryside Act 1981, it is illegal to keep unhatched eggs. So any eggs removed from a nest box must be disposed of.

Our bird box housed a beautifully delicate nest of moss and soft lining. I suspect some of the lining was selected from the dog hair I pegged out during early spring.

A single egg remained in the nest, unhatched and consequently abandoned after the rest of the inhabitants departed. The bird which never was.

The bird family

Last season, the box was used by a blue tit family. Blue tits tend to start looking for a nest site in February. March will be spent building up energy reserves, towards the business of raising a family. The female builds the nest alone in April. The outer layer is moss, and she lines the nest with something warm such as fur and feathers.

In May, the egg laying commences. One egg a day towards a clutch of up to sixteen eggs. To prepare to incubate, she plucks feathers from her abdomen to create a ‘brood patch’. This area of skin hosts numerous blood vessels, which are perfect to keep the eggs warm until they hatch.

Hatching happens around two weeks later, during which time some males will find bits of food for the female they are paired with. All females need to supplement their diet with daytime forays.

The chicks hatch in late May, and the parents are thrust into an exhausting feeding cycle. As they grow, the young can eat up to 100 caterpillars a day … each! By early June, the young are ready to fledge the nest. The parent birds sit outside the box, calling to them to encourage them to venture out. In the first few weeks after fledging, the parents continue to feed the young, while they in turn begin learning how to find their own food.

Back to the box

Having cleared the box, I swilled it out with boiling water. This will have killed any parasites which might have remained. The box is now drying out, ready for a handful of hay before I set it up in the tree again. And then wait, and hope that a family (perhaps the same one) sets up home there before the spring.

Top of my list for bird information websites is the Royal Society for the Protection of Birds, which also has a selection of children’s pages. The Wildlife Trusts and the British Trust for Ornithology also have a lot of useful information.