Bird Box Basics
In the UK, bird numbers have experienced a decline in the last 50 years, and the disappearance of natural nesting sites is contributing to this. The addition of bird boxes to your garden is a great way to support struggling populations, providing them with somewhere safe and secure to build their nests during the breeding season.
Many of us may buy or build bird boxes for our gardens, however, few probably realise that there are some specifics things to take into consideration to ensure your bird box is suitable and safe for your resident birds. These points are simple, but crucial for providing a safe and functional nesting site. They revolve around:
The type of box you install.
The location of your bird box.
When the box is installed.
Predator prevention techniques.
Birds are most vulnerable during the breeding season, and the purpose of a bird box is not to provide us with a view of comings and goings of parents or the development of chicks. It is vital that once inhabited, bird boxes are left alone, and the birds left undisturbed. Typically, the breeding season begins in spring, however, in some species it is beginning earlier and earlier (climate change being largely to blame).
Installing your box by the end of February should allow birds to find it in time for breeding. However, the earlier you install it the better. If you put up your box at the end of autumn it can act as a shelter during the winter months. Birds may then return to the nest box the following spring.
The first thing to consider is the type of box you choose. Different species are suited to different types of nesting boxes, so try to reflect on which birds you’ve seen in your garden, so you can cater to them. If you are unsure what species frequent your garden, you can install a variety of boxes so that you are able to accommodate a range of species.
The most common bird boxes, used by the majority of UK garden birds, are box shaped with a small circular opening, located usually on tree trunks or fences. However, swifts and house martins, for example, are better suited to nesting cups placed higher on the walls of your house. Then there are house sparrows, who prefer boxes placed under the eaves of your roof. Owls and woodpeckers generally utilise larger boxes, that are placed higher up in a tree, around 3-5m.
Once you’ve chosen your bird box or boxes, it’s time to think about where to install them. As mentioned, the general location is usually species dependent, but the overarching theme is that they are somewhere safe, with minimal risk of harm from the weather or from predators.
Other than a few species who prefer their boxes lower to the ground, installing your box around 2m high can help keep birds safe from predators. Here are some pointers:
Shrubbery can provide cover and obscure a predators view of the box; however, the entrance should remain free from obstruction.
Wind and rain can cause harm to eggs and chicks, so place your box near the shelter of buildings or trees; alternatively, face boxes north east to protect against the strongest winds and bright sun.
Angle the box down slightly, to allow rain to run off instead of accumulating inside.
As for the installation itself, if attaching to a trunk, use non-rusting wire instead of nails to avoid damage to the tree. Just make sure to check the fixing every few years as trees grow in width as well as height. If you have multiple boxes within your garden, ensure they are not close to one another, as proximity during a vulnerable period can promote aggression. Similarly, keep bird feeders and baths a good distance from you bird boxes, to prevent breeding birds from being disturbed. Lastly, do not be disheartened if your box isn’t in use instantly, leave it where it is for another season, and if it remains unoccupied, then you can think about trying a new location.
Protection from Predators
It is impossible to completely ‘predator proof’ your bird box. However, there are some tricks and adjustments you can use to help keep the nest safe.
Predators of common garden birds in the UK include mammals – like squirrels, cats, mice, and stoats – and larger birds – such as jays, magpies, and crows. Below are some tricks to help you create a safe nesting box for your local birds:
If you know your main visitors are small garden birds, choose boxes with small openings, which helps reduce access by predators.
Installing your box within a thorny plant can help to deter cats.
If your box, like many, comes with a perch attached, remove this as it can facilitate squirrels and other animals reaching in to grab eggs or even chicks.
Metal plates can be fitted around the entrance hole to prevent any determined animals from chewing the hole bigger to gain access.
Rubber tubes can be attached to the entrance (these can be DIY or specially bought), making it harder for animals to reach in, without affecting parents entering and exiting.
Choosing or building a box with a long extending roof can prevent cats from reaching down into the boxes from the top (this can also help keep rain out).
One important thing to note however, is that should you witness a predator gain access to your bird box, sadly the best course of action is to leave it. By trying to shoo the animal away you risk causing the adult birds to flee, not to mention the predator will then likely just try to find another nest to raid.
Between the nesting seasons it is a good idea to give your bird box a clean, this can prevent the spread of diseases and parasites. Although, it is important to leave the box alone until at least august, or even the autumn, to be sure it is unoccupied.
Maintenance and Cleaning between Seasons
Once sure the box is empty, you can use a mild bleach or a disinfectant to clean the insides, rinsing well after to remove any chemicals. Leaving the box to dry properly in the sun will prevent mildew from forming.
Droppings and other material are best disposed of in a sealed bag and not your lawn as this could lead to the spread of parasites. If the box contains unhatched eggs, then legally you may only remove these between August 1st and January 31st. While cleaning your boxes, check for any protruding nails, large splinters, or other hazards. Then, simply reinstall your box and wait for your guests to arrive!