It may be possible to cut down trees or modify roosting and resting sites used by cormorants to make a site less attractive. However, this will clearly not be appropriate for rivers or larger sites where there are likely to be numerous alternative roost sites available. The adverse environmental impact of removing trees would also need to be considered. Note that nests are protected under the Wildlife and Countryside Act 1981 when in use or being built and must not be damaged/destroyed without a licence.