Bringing Reedbeds to Life Water Vole and Mink Survey of five key reedbed sites in England in 2009, 2010

Quality Control

These data have been gathered by trained field-workers and the data are of a high quality. These data have been mapped and checked for sensitivities and typographical/geographical errors.

Method steps

1. Water vole raft survey methods: 21 water vole rafts were set out at each of the three key sites (Hickling Broad, Ham Wall and Stodmarsh), two weeks prior to the first checks in June 2009. Rafts consisted of foam sandwiched between two pieces of ply measuring 48 x 30 cm with nuts and bolts, designed according to expert advice (T. Moorhouse pers. comm.). Twine was used to attach the raft to the water trap pole. Droppings or latrines of any mammal left on the raft were recorded. Feeding signs (e.g. a small pile of chewed roots or stems) were also recorded. The top sides of the rafts were cleared of water vole sign whenever it was detected, to reset the rafts for the next monitoring period. Habitat around the water vole rafts was surveyed in summer June/July 2009 as part of the invertebrate survey and in winter Jan/Feb 2010.
   
   Mink raft methods: Mink raft surveys for water vole and mink sign in ditches were conducted at all five sites. Mink rafts were built according to the Game and Wildlife Conservation Trust Mink Raft specifications, with a clay/sand mix tracking pad. Eight rafts were placed at five reedbed reserves. Rafts were placed where two or more watercourses join to increase chances of detecting mink. Checks for mammal droppings or latrines were carried out fortnightly between April 2009 and October 2009 with an additional check in January 2010 at Ham Wall, Hickling Broad and Stodmarsh. Water vole tracks and feeding signs on rafts were also recorded. Any water vole sign detected was cleared from the raft to reset the raft for the next monitoring session. A survey of the habitat around mink rafts was also carried out, focusing on dimensions of the water body and surrounding vegetation.
   
   Surveys were designed by Donna Harris in consultation with various mammal experts and carried out by RSPB staff and volunteers.

It is recognised that this dataset is only from two years and that water vole and mink move around from year to year.
Bringing Reedbeds to Life Technical report with further method descriptions will be available after 31st March 2011 at www.rspb.org.uk/ourwork/projects/details.aspx?id=tcm:9-210865"