Stephen Colton's Take on Nature: Advice on putting nest boxes in your garden
A FRIEND recently asked me to write about using nest boxes to encourage birds to nest in our gardens. A nesting box and its occupants can enhance any garden during late spring by providing endless hours of pleasure as parent birds enter and exit to rear chicks within.
Nest boxes replicate woodland nest sites for species which have traditionally used holes and crevices in trees. Blue-tits and Great-tits are typical woodland birds equally at home in the modern garden and will readily take up residence in boxes if provided. Other species like sparrows, starlings and robins can also be attracted, given the right location, type of box and size of entrance hole.
A first consideration is to identify which species you wish to attract. The size of the entrance hole at the front of the box will determine which bird you are likely to have.
A hole size of 25mm is perfect for blue tits and will exclude larger species like the great-tit and house sparrow which require hole sizes of 28 and 32mm respectively. For larger birds again like the starling an entrance hole size of 42mm is recommended. An open-front box can be used to encourage robins and wrens.
Ideally boxes for blue and great tits should be fixed two to four metres up a tree or wall and positioned facing somewhere along a north to east arc to avoid strong sunlight from the south and the wet prevailing winds from the west. Make sure the birds have a clear flight path to the nest site without any obvious obstacles and do not use a box with a perch on its front as this will encourage intruders like starlings.
It is normal to expect only one nesting pair of any one species unless the garden is very large, encompassing more than one territory and with plenty of natural food. Exceptions to this are house sparrows and house martins which are colonial nesters.
By putting up different boxes several species can be attracted.
Blue and great tits are probably the most colourful and desirable occupants and for them the box should ideally be no more than about 30 metres away from trees where they can collect insects for their young.
They begin investigating boxes as early as February and from March onwards they will enter them more frequently and for longer periods. Both species will hammer the rim of the entrance hole, an instinctive action thought to mirror their behaviour at natural sites where the hole may need enlarging. It could also represent a ‘staking claim' to the box.
The birds can also be heard hammering the inside walls of the box.
The great and blue tit begin nesting in earnest during April when the female will begin the process of building a cup nest of moss, lichens, grass and wool. Some siders' webs and feathers may be mixed in.
After laying anything from seven to 12 eggs, the female will incubate, while being fed by the male, for about 14 days. The newly hatched chicks will then be attended to by both parents during an exhausting twenty day period of feeding, after which the fully fledged birds will leave the security of their box in late May or early June to face the many perils of the outside world.
Come the autumn, empty out the old nest material and any unhatched eggs or dead chicks. Wash out the box with boiling water to kill off any parasites lying in wait for next year's brood.
Here's hoping you enjoy some residents in your new nest box, Carmel.