Nesting bird surveys – are necessary during the bird breeding season (March to September) and are typically conducted immediately prior to intended disturbance, such as clearance works, vegetation removal or building demolition. Some species of ground nesting bird such as skylark and lapwing will readily nest on construction sites where there has been a lapse between clearance and development, therefore surveys may be required prior to recommencement of activities. Ideally, works with potential to disturb nesting bird habitat would be conducted outside of the nesting bird season i.e. October to February inclusive.
Breeding bird surveys – are distinctly different from nesting bird surveys in that they aim to establish the importance of a site for birds during the breeding season. They are usually undertaken at the design stage of a proposal. Survey methodology involves the BTO’s (British Trust for Ornithology) common bird census technique and territory mapping to provide an estimate of the abundance and distribution of occupied territories during the breeding season (March to June inclusive). The survey results are used to assess the predicted development impact on bird species of conservation concern, and to formulate appropriate mitigation and/or compensation measures should they be needed
Wintering bird surveys – are usually required if proposals have potential to impact upon potentially important bird wintering sites, such as sites within close proximity of wetlands. Survey methodologies vary according to the habitats present, the site’s proximity to conservation sites and the species concerned. The results to allow an assessment to be made of the importance of the site for wintering by birds and to formulate appropriate mitigation and/or compensation measures should they be needed.