Finally, bird nesting is a perennial problem and can be a real menace and nuisance.
Under no circumstances should you attempt to light a fire in a chimney where you suspect bird activity.
Cowls and terminals can be fitted once the nest has been removed to prevent subsequent activity. Again, I can recommend people for this work. Do be aware that it is an offence to tamper with, or prevent parent birds returning to a nest during the nesting season. Please visit the RSPB website for more information. This means that nest removal has to take place during the autumn and winter months.