How can you deter house martins nesting under eaves?

To deter house martins from nesting under eaves, you can install physical barriers such as bird netting or spikes that prevent access to nesting sites. Additionally, using reflective materials or hanging plastic deterrents can make the area less attractive. Regularly cleaning the area to remove any nesting materials can also discourage them from returning. It's important to ensure that any deterrents comply with local wildlife protection laws.