Group Projects

The group is currently involved in several ongoing studies, which are summarised below. Please click on one of the links, or on the paragraph headings, to view details of the projects. These extracts are taken from our annual reports.

Our Constant Effort Sites (CES)
Since 1984 the group has run a constant effort ringing site as part of its ongoing study of local birds and their population dynamics. The Constant Effort Sites (CES) scheme is a national standardised ringing program set up by the British Trust for Ornithology and has been running since 1983. The nets are set in the same pattern, for the same time period at regular intervals through the breeding season at around 130 sites throughout Britain and Ireland. The scheme provides valuable key information on changes in population size, changes in breeding success and adult survival rates for 28 species of common songbird.

The first of the group's CES studies began in 1984 at West Thurrock, on the north bank of the Thames. This site was first used by the group in 1977 and a regular ringing program continued until 1987 when the site was developed as a shopping centre and industrial park. In 1987 the group started a new CES at Littlebrook Power Station near Dartford in Kent, where the study ran until 1996. This site was the original home of the group and had been used as a study area since 1968 until it became untenable due to vandalism and the impending development of the area as a science park. More recently the group has embarked on two new CES studies; the first at the Jeffery Harrison Reserve at Sevenoaks, Kent was started in 2000; the secord was started in 2003 at Crossness Nature Reserve, Thamesmead, Greater London and both are beginning to provide a useful insight into the population dynamics of the local bird populations, as well as adding valuable data to the national picture.

If you would like to learn more about CES? Click this link to the BTO web site.

Nest Box Projects
Since 1989 we have been monitoring the nest boxes at the Jeffery Harrison Reserve at Sevenoaks and more recently at four other sites. This report analyses the productivity of the nest boxes used by Blue and Great Tits, including the date of the first egg laid, the number of eggs laid and the number of young that eventually fledge.

Greylag Goose ringing
Every year since 1985 the Dartford Ringing Group has carried out a roundup of the geese at the Jeffery Harrison Reserve at Sevenoaks (previously the Sevenoaks Wildfowl Reserve). This involves a large number of ringers, canoeist and other helpers and takes place during the period when the geese are flightless in mid June. The principle target of this study is the Greylag Goose flock which is descended from birds introduced at Sevenoaks by the late Jeffery Harrison in the 1960's. This study has yielded a large amount of data not only on the population dynamics of the Greylag Goose but also on the movements of the descendents of the reintroduced birds and we hope to be able to publish this in the near future. In the meantime, please take a look at last years ringing data on this link.

If you would like to attend the roundup as a ringer or helper please contact us at drgwebmaster@btopenworld.com.

Reed Warbler Biometrics This will download a pdf file.
The group ringed a total of 6,359 Reed Warblers during the period 1968 to 1995 at a number of sites in Kent and southwest Essex. This short paper on wing length and body mass uses data from three of these sites: West Thurrock Marsh, Essex; Littlebrook, Dartford, Kent and Lea Bridge, Hackney, Greater London. The wing lengths and weights of a sample of adult Reed Warblers is analysed to examine differences between males and females and the variations over the period May to August.

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