Spotted crake national survey in the UK in 1999

Quality Control

Data were checked for spatial errors using MapInfo. Where grid references for calling males were omitted in raw data central grid references OR site names were entered against each record.

Method steps

1. Volunteers and site wardens/managers visited sites at which spotted crakes had been recorded 1988?98. For each site, evidence of the presence of a spotted crake varied from a singing male to a bird seen in the autumn. Sites were divided into two groups: high priority and low priority. High priority sites were those at which singing birds had been recorded more than once in the last ten years and extra effort was made to cover all of these sites. Low priority sites were the remainder and within these, less effort was placed on surveying sites where birds had been seen only in the autumn. General habitat data were collected as part of this survey, both from an area of 5 m נ5 m surrounding the spotted crake singing locations and from ten randomly selected 5 m נ5 m squares within sites. Details and description of these data can be found in Gilbert (2002).
   
   High priority sites were visited once a week during May and June (at least eight visits), whilst the remaining low priority sites received three visits, one in the first half of May, the second in the second half of May and the third in the first half of June. Observers were asked to conduct their survey from half an hour after sunset (as soon as it was dark) up to 02:00 hours British Summer Time and preferably to avoid cold, wet and windy conditions. The census method used relies on counting singing males to give a relative index of breeding pairs (Gilbert et al. 1998). Observers were asked to mark on a map the boundary of the site to be covered and the position of listening points within 500 m of all suitable habitats. Observers listened for five minutes at each point and recorded the position of singing birds on a field map, coding all records according to visit and bird number. Spotted crakes heard or seen before or after the survey period, or during an extra visit, were recorded separately.

Sites surveyed in 1999 ranged from north Scotland to the Channel Islands. Sites chosen for survey based on where birds had been recorded in 1988 ? 1998. Two sites in north Scotland from where previous information was lacking but which seemed very suitable for spotted crakes, were also visited