2024 Dipper and Grey Wagtail survey

Background

It is well known that Dippers and Grey Wagtails are good indicators of water quality. Their diet of freshwater invertebrates and flies are very susceptible to changes in the aquatic environment. Recent climate changes including increased rainfall and incidences of flash flooding, may have contributed to more runoff from fields and roads into water courses. This may have caused a decline in water quality and consequently reduced numbers of Dipper and Grey Wagtail.

Cornwall Birds, in association with other organisations, are looking to complete a tetrad-based survey of suitable habitat to establish the breeding distribution and population of these two species. The last survey of Dipper and Grey Wagtail was during the Cornwall Bird Atlas in 2000-09. Dippers were found in 92 tetrads and Grey Wagtails in 182 tetrads. The aim in 2024 is to resurvey all tetrads where both species were found during the Atlas period and where evidence of breeding has been received subsequently. In 2025 we will widen our search to include other locations with suitable habitat.

To take part in the survey, please check out the previous Cornwall Bird Atlas distributons of Dipper and Grey Wagtail and find a stretch of river near you. Please then contact us via email ([email protected]) to request a site and avoid duplicating any effort. Full survey instructions and downloadable forms can also be found below.

Survey aims

  1. To record the presence or absence of Dipper and Grey Wagtail within each tetrad containing suitable breeding habitat (fieldwork period is between 15th March and 15th June)
  1. To prove breeding by visiting the tetrad and looking for signs of Possible, Probable and Confirmed breeding (any time during the field work period and any number of visits may be made)
  2. To make an estimate of the population of each species in each tetrad by counting the number of adult birds on either two one-hour visits (one between 15th March and 30th April and another between 1st May and 15th June) or one two hour visit (between 15th Apruil and 15th May)

Habitat recording

Recording the type of water course and the habitat surrounding it is very useful (but not essential) and will enable us to identify preferred associations for breeding Dippers and Grey Wagtails. This is best done separately, not when undertaking the survey. The habitat recording form follows common habitat types using the standard four level coded system used in BTO Waterways and Breeding Bird Surveys.

Recording the information

Full details of the survey methods can be found on the survey information form (download here) along with extra detail on habitat recording (download here).

Once you’ve completed your survey, you can complete the recording form (download here) and the optional habitat recording form (download here). If you have any queries on either of the forms or the survey then please contact Bruce Taggart ([email protected]).