A Breeding Bird Survey, or BBS, is the assessment of territories and species of breeding birds on site. BBSs are needed to inform the requirements of the mitigation hierarchy (avoidance, mitigation, compensation and enhancement measures), where potential impacts to breeding birds have been identified during an initial scoping survey (such as a Preliminary Ecological Appraisal) or a BBS has been requested by the planning authority. The aim of a BBS is to gather as much information about breeding birds on site and the surrounding area as possible, so that the potential impacts of the proposed development on breeding birds can be assessed. This is usually presented in an Ecology Surveys report and is achieved through a three-part process: a desk study, field surveys, and an evaluation/impact assessment.
A desk study involves obtaining details of the landscape surrounding the site, so that the ecologist can assess both the likelihood of birds breeding on site (including specific species) and the potential impacts of the develop on ecologically important sites and habitats in the surrounding area. This study includes identifying Priority Habitats and Statutory Designated Site within one kilometre of the site and will often involve contacting the Local Environmental Records Centre for information on notable/protected bird species recorded within one kilometre of the site.
Field surveys involve an experienced ecologist walking a transect and recording the behaviour, species, and territory of all birds on site, where possible. The aim is to assess the breeding status of all birds on site. The transect route is pre-mapped and is designed to focus on habitats and features of high value to breeding birds, such as hedgerows, lines of trees, scrub, and waterbodies. All parts of the site are visited on foot within 50 metres, where possible, or closer where visibility may be reduced, such as within parcels of woodland. The transect is walked at a slow, ambling pace, and stops are made at strategic points to encompass a wider range of potential breeding bird species on site. Species are identified using high-powered binoculars or by sound, and age and sex are also recorded, where possible. Breeding status of birds on site is recorded, in reference to the EOAC (European Ornithological Atlas Committee) Breeding Evidence Categories (confirmed breeding, probable breeding, possible breeding, and non-breeding). Habitats on site and current land management are also recorded during field surveys. Periods of heavy rain, strong wind and fog are avoided. Usually, six site visits are recommended, typically lasting at least two hours each. The transect route will usually be reversed between each visit, in order to gather the full range of breeding birds using the site. Most visits comprise a ‘dawn visit’, which begins at sunrise. However, at least one of six visits will comprise a ‘dusk visit’, which begins half an hour before sunset. The number of visits, and proportion of visits conducted at dusk, will depend on site specific conditions, such as the size of the site, the habitats present and previously recorded species that occur within the desk study. It is worth noting that field surveys must be undertaken between late March and early July, and spaced at least one week apart from one another. In special cases, such as where more than six visits are required, surveys may be recommended to take place between February and September. Permission from the landowner and a full risk assessment are required prior to field surveys.
With the information from the online data search and field surveys, the ecologist can then carry out the evaluation/impact assessment of breeding birds supported on site and whether the proposed development will have an impact on them. Here, the site will be categorised for its significance for breeding birds (site significance, local significance, county significance, etc.), as well as assessed for its ability to support foraging and commuting birds. The assessment made is presented in a report, includes an evaluation of the potential impacts of development and details requirements of the mitigation hierarchy. The reports we write are in accordance with the up-to-date CIEEM guidelines for ecological report writing. Ecological reports are valid for 12 months so must be submitted to inform a planning application within a year of the report being issued. An updated survey may be required if the report is not submitted in time.
More information about bird surveys is available on our website here. Alternatively, you can contact us here.
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