Practical surveying and monitoring techniques are essential for anyone involved in studying or managing squirrel populations in forests and woodland in Britain. Survey methods can be used to establish the presence of squirrels in a particular area and, if used systematically, can detect significant changes in the distribution or abundance of populations and species over time. Data gathered from surveys can be used to monitor how threatened populations of red squirrels are responding to conservation management or to environmental change, and they can also be used to assess the efficacy of grey squirrel control measures. This Practice Note describes how to plan a survey and gives guidance on which method(s) to use. Five indirect survey techniques are described, which are based on either sightings or signs of squirrels, and advice is given on their suitability for different types of habitat at different times of the year.