Abstract from BTO Research Report No 316:

Glue, D. & Carter, N., (Oct 03)

Lark Rise Farm, Barton, Cambs (Plot 1571).
The Countryside Restoration Trust Report on Breeding Birds 2002
ISBN 1-902576-78-0

Executive summary

INTRODUCTION

Year 2002 saw a fourth successive good annual survey of the breeding bird community of Lark Rise Farm, Barton, Cambridgeshire. The annual procedure deploys the BTO’s Common Birds Census (CBC) mapping technique, whereby the breeding bird populations on the farm are assessed by delimiting clusters of territorial activity. This farm, modest in size by east of England standards (53.2 ha), was purchased by the Countryside Restoration Trust (CRT) in 1998. Thereafter, it has been managed for financial gain, whilst attempting to improve the potential for wildlife. In Year 2002, the farm was given over chiefly to arable production (as in previous years), winter wheat and undersown spring barley covering some one-half of the total area, but with an ongoing crop rotation programme. In 2002, fields of broadly similar size were devoted to oilseed rape (autumn sown), spring beans, grass cut for hay and, finally, fields of set-aside: to natural generation and bare fallow. A small, but significant area (2% of the plot), comprised new woodland planting, enhancing an ongoing hedge-planting regime – see Annual Habitat Summary Form. The management plan added to further sympathetic conservation orientated work undertaken in previous seasons with birds in mind (Carter and Glue 2000, Carter and Glue 2001, Glue and Carter 2001).

2. METHODS

A complete mapping census was undertaken using the guideline methodology laid down by the BTO’s CBC procedures (see Marchant et al. 1990). Eight full visits were made to register all bird activity from late March through to the end of June, including a productive evening visit in mid-June (Visit H) to detect potential crepuscular species. The field effort expended, some 23.5 hours, was somewhat less than in previous years (most notably 2000 and 2001). Similarly, eight full visits represents a third fewer than in 2001. Nonetheless, the procedure deployed, by the same observers, satisfies acceptance as a full census. The findings are considered a broadly comparable set of data, allowing a valid comparison between years, though with certain reservations (discussed below). To consolidate the project, the fieldworkers should attempt to complete 10 visits (to include two evening visits spanning 10 days or more), over the same calendar period, where possible in fair weather conditions.

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