Waveney Bird Club

Introduction

During 2010 and 2011, Waveney Bird Club conducted a number of ringing sessions at a small reedbed site located at Western Farm in the village of St James South Elmham.

Site description

The site is located in an area of largely arable farming, on the edge of the village of St James South Elmham, grid reference TM 31436 80968 (diagram 1). The reedbed measures approximately 0.3 hectares and slurry and drainage ponds are located nearby. The reedbed was established by the landowner to filter pig slurry from a neighbouring intensive pig unit. The dominant flora species in the reedbed is Phragmites australis.

Diagram 1, site and surrounding land, site marked in red outline

The surrounding land comprises mainly large scale arable fields, up to about 40 hectares in size. Typical crops include winter wheat, peas, sugar beet and oilseed rape. There is in general low habitat connectivity and low biodiversity due to a lack of hedgerow features, mature trees or woodland areas. Farm and garden ponds form the main water features near the site.

The site is within a few kilometres of Metfield Airfield and Rumburgh, which hosts good breeding populations of Yellow Wagtails.

Ringing activities

Ringing studies were started to determine the origins of target species, which included Yellow and Pied Wagtails, Reed and Sedge Warblers, Swallows, Sand Martins and Reed Buntings. Observations had shown that the reedbed was used by Reed and Sedge Warblers along with Reed Buntings during the breeding season and as a roost site by Yellow and Pied Wagtails, Swallows and Sand Martins. Another aim of the project was to determine the importance of the site as a migration stop-over point.

Ringing commenced in August 2010 with sessions starting approximately one hour before dusk, to allow sufficient time to set up mist nets before birds come in to roost. The purpose of ringing activities was to target the birds that utilise the reedbed for roosting overnight.

The mist nets target passerine birds and between 90 and 150 metres of mist net were deployed at each session.

Ringing sessions were conducted in suitable conditions with low wind and no precipitation, on the dates below. Five sessions were conducted in each year.

• 9 August, 16 August, 23 August, 30 August and 11 September 2010
• 6 March, 26 June, 14 August, 21 August and 10 December 2011

The birds processed during each year are shown in table 1:

Analysis

A total of 13 species have been processed. 247 birds were processed in 2010 and 328 in 2011, totalling 575 over the two years. The number of birds processed increased by 32% from 2010 to 2011 but this was not ascribed to any single species; numbers increased over the range of species mainly using the site. It is not possible to determine the reason for the increase in numbers processed year on year based on only two years’ data. With continued mist netting for future years a trend may be established, which would allow further analysis.
The highest count of birds processed in any one session was 118 birds on 9 August 2010. At this stage in the breeding season the population of most species would have been at a peak due to recruitment of juveniles but before departure to winter grounds by the migratory species.
Reed Bunting form the majority of birds processed, up to 38% in 2010, with Pied Wagtail the next most abundant, up to 28% in 2010.
The site is used for roosting by long distance migratory passerines such as Reed Warbler, Yellow Wagtail, Swallow, Sand Martin and Whitethroat that winter in parts of Africa. This could include birds breeding in the local area and birds stopping over from northern areas, on their journey south. This site could play a key role in providing an important roosting resource to these species.
Mostly sedentary species such as Reed Bunting and short to medium distance migrants such as Pied Wagtail that may migrate to Europe are also using the site for roosting.
The species assemblage that roost on the site are mostly typical of birds that occupy farmland sites and indeed include species such as Reed Bunting, Yellow Wagtail and Linnet which are being targeted in conservation efforts for farmland birds.

Notable controls

Recoveries of birds ringed at St James include: a Sand Martin recaptured at Fen Farm, Bungay; Swallows at Iken Marshes and Orfordness and a Yellow Wagtail at Belton Marshes, near Great Yarmouth.
Birds caught at St James carrying rings from elsewhere include a Sedge Warbler that was ringed five days previously at Red Row, East Chevington, Northumberland, two Sand Martins from Homersfield and a Swallow from Orfordness

Conclusion

Based on the abundance of birds that utilise this site for roosting, it is clearly a very important resource whilst only covering a compact area of only 0.3 hectares. The site is a habitat island and valuable stopover point for migratory passerines, in the context of the surrounding landscape of large scale arable fields with relatively low biodiversity and foraging resources for birds.
The site provides a valuable ringing benefit due to the high numbers of birds processed per session. It allows the efficient collection of important control data to monitor and track movements of local and long distance migratory birds.

Etienne Swarts
January 2011