IMIS

Purpose of data capture

The majority of records in the dataset were obtained during surveys aimed specifically at checking riparian wildlife in general or otters in particular. A few 'casual' records are mostly from visitors to nature reserves and/or other naturalists and regular observers of wildlife. A very few records are from untrained members of the public who just happened to see an otter and contacted the Wildlife Trust with a one-off record.

Methods of data capture

Our otter records come from several sources, mostly derived from Gloucestershire Wildlife Trust reports and including older documents:

• Field observations by Gloucestershire Wildlife Trust staff, principally the Water Vole Project Officer and the Severn Vale Project Advisors.
• Observations by GWT members and members of the public, principally through the Severn Vale Project Otter monitoring scheme.
• Field observations by Cotswold Water Park Trust otter monitoring scheme.
• Other reports, mostly unpublished, by a range of authors.

Almost all the records relate to observations of live otters in the field, or their recent signs (e.g. road casualties, footprints, food remains, fresh spraints and anal jelly). However, users of the data should bear in mind that there may be some records which relate only to older otter signs, such as old tracks/trails or disused holts.

Geographical coverage

Source records are derived from six- or eight-figure grid referenced observations. The records are for the whole of the administrative county of Gloucestershire. Please note that this does not include the administrative area called South Gloucestershire.

Temporal coverage

Records range from 1993 to 2011, with concentrations of records from the recent activities of the Cotswold Water Park Trust 2007 - 10 and the recent activities of Gloucestershire Wildlife Trust staff from 2007 - 11.

Data quality

Data relating to the otter surveys should be regarded as of high reliability where species identification is concerned. Casual records are generally thought to be of reliably-identified otters, but come with a slightly higher risk of confusion with similar species. Very doubtful reports of live sightings are not added to the database. The temporal and geographic spread of records is highly reliant on the scope of the main surveys involved, and should not be relied upon as a comprehensive guide to the exact distribution and abundance of otter in Gloucestershire for any period of time. Older records in particular should be seen only as a guide to those stretches of river which have been seen to be hospitable to otters in the past.