Blocking those entrances with hardware mesh wood scraps expanding foam or other barriers can keep birds from nesting but be sure there are no birds already inside the cavity when the blockage is installed.
Preventing birds from nesting in eaves.
All birds their nest and eggs are protected by the wildlife countryside act 1981 and it is thus an offence to damage or destroy an active nest or prevent parent birds access to their nests.
How to stop birds nesting swallows and house martins building their nest at the eaves of a dwelling can be a big problem.
If you think it ruins your house s look just endure the breeding season and wait until the birds migrate.
Often birds choose these protected sites for nesting.
It is an offense to damage or destroy an active nest or prevent parent birds from returning to the nest.
One of the efficient on how to stop birds from nesting in the gutter is to install nettings.
You just have to cover the slope of the eaves and staple the edges carefully so the birds won t go past the barrier.
In the case of birds such as the barn owl that are listed on schedule 1 of the act it is an offence even to disturb the birds when at or near the nest.
The most effective way to prevent birds from nesting is with bird exclusion products that is products that exclude birds from the area.
Also there are certain birds such as owls bearded tits golden eagles who are specified in schedule 1 of the legal act outlining that it is an offense to cause disturbance to the birds when they are in or near their nest.