These fumes are potentially lethal so it's worth getting a certified cimney specialist in to check the flue. When a bird has found a suitable place to build a nest, they will generally return to the same place year after year unless you cap the chimney with a bird guard.
Some of the biggest issues that can come from having a birds nest in your chimney apart from the carbon monoxide build up is that they can become a fire risk as well as debris falling down the chimney including twigs and dead birds.
Different birds build different sized nests, for instance a Jackdaw nest can be extremely large and in no time at all you may find your chimney completely blocked which results in the fumes from your open fire or stove coming straight back into your home.
We are able to provide a range of bird guards to suit the aesthetics of your home including various colours and shapes such as decorative bird guards.
The bird guards we use are extremely strong and built to last and can usually hold out during severe wind and storms so you can be rest assured your investment will stand the test of time.