Breeding Bird Surveys
The breeding bird season generally runs between March and August, during which time all actively breeding birds (this includes building nests, laying/sitting on eggs and rearing young) are protected under UK legislation. If a habitat that is considered to be suitable for breeding bird activity is to be disturbed/damaged during the nesting season, a Breeding Bird Survey (BBS) will be required prior to works commencing on that habitat.
Survey methods are based on the British Trust for Ornithology (BTO) Common Bird Census, which involves mapping individual bird species territories. Alternatively, for larger sites or open habitats a walked transect may be more suitable. The map will show the location of singing/non-singing birds, birds carrying food and/or nesting material, territorial displays and active nest sites. A number of early morning visits are often required.
Nesting Bird Surveys
Nesting bird surveys are applicable to small-scale projects such as removing a small number of trees, a short section of hedgerow or carrying out works on a building where birds may be nesting. A nesting bird survey is generally undertaken immediately prior to works commencing at a site and involves a visit by an ecologist who will ensure that no active bird nests are present. If no active nests are detected works can proceed as planned. If active nests are present works will need to be delayed until all chicks had fledged. It is sometimes possible to cordon off the active nest(s) and work within a safe distance. Ideally all works should be timed to be undertaken outside the bird nesting season (March to August inclusive).
Wintering Bird Surveys
Wintering bird surveys provide an assessment of the bird species and numbers present at potentially important wintering sites. One of the contributing factors to the decline in farmland bird species is thought to be due to reduction in winter seed availability. The UK also provides important habitats to migratory winter birds. Wintering bird surveys involves a visual assessment of the site in question, counting species (and numbers of) wintering birds.
Vantage Point Surveys
Vantage point surveys are often undertaken as part of wind farm developments due to the increased collision risk for resident and migratory bird species. In addition wind farm development projects can also result in removal of valuable bird habitat.
Vantage point surveys include making observations of flight direction, height and duration and often require several visits in order to gain a representative sample of avian activity. The resulting data can be used to calculate the likelihood of bird collisions as a result of turbines.