Lark Valley Canada Goose Study by Dr Tony Martin
The annual reports of Suffolk Birds have shown that the numbers of Canada Geese breed 1; in the County, and the size of the wintering flocks, have increased dramatically over the ps decade. There are indications that they have become more mobile and interchange betwe; sites is frequent. In an attempt to assess these movements 251 Canada Geese were colou ringed in 1986/87. The captures were confined to the west Suffolk gravel pits of Cavenha and Lackford and were conducted whilst the birds were flightless when completing their mk summer moult. Of the 251 birds, 35 (22 juveniles) have so far been recovered dead. Causes of mortalic were reported as "shot — 66%" "hitting wires — 6 % " , "unknown — 11%" or "poisoni by bacterial toxin — 17%". The latter was almost certainly the case for six juveniles four: dead on a shallow pool at Cavenham, where warm waters encouraged high levels of bacteria On the brighter side many of our ringed geese have been reported alive at several site in the Lark Valley and they are always at Cavenham itself. Family parties of colour-ring« birds became a feature of the 1986/87 and 1987/1988 winter. One juvenile reach« Finchingfield, Essex, a straight-line distance from Cavenham of 38 kilometres and the link between the Lark Valley flock and that of Holkham Park, Norfolk was established. An eight year old goose, ringed at Holkham, was 'controlled' at Cavenham in 1986 and a second, from that area aged 11 years, was captured at Lackford in 1987. The most distant sighting so far involved an adult ringed at Lackford and observed on Sutton Bingham Reservoir in Somerset. Of the 34 geese ringed in 1986 and recaptured in 1987, four had lost their plastic colourrings and two their metal rings. Colours used are red, white, blue yellow, orange and green. 1988 will see an extension of the ringing to cover flocks at Ixworth and the author would be grateful to receive details of observations of any colour ringed Canada Geese. Acknowledgements: I would like to thank those who assisted on the catching weekends. Their efforts were nobie and sometimes heroic. Permission to ring was kindly granted by Allen Newport Ltd., Atlas Aggregates Ltd, the Suffolk Wildlife Trust and Mr Bernard Tickner. The financial support of Allen Newport Ltd is gratefully acknowledged. Dr Tony Martin, do British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET.
Winter status of the Hen Harrier in Suffolk 1984-88 by Roger Clarke
It has been generally remarked that Hen Harriers were less in evidence during the 1986/87 and 1987/88 winters. Has this been reflected in the Hen Harrier Winter Roost Survey counts? Table 1 shows Suffolk data for every January since the survey began except 1988. The monthly counts have shown that December, January and February are usually the peak months in eastern England (Humberside, Lincolnshire, Norfolk, Cambridge, Suffolk, Essex, Greater London and Kent). January is shown as a representative extract. Although deep snow shortly before the January 1987 count may have affected the result, even the best Suffolk total count that winter was only 18 birds (15th March 1987). The fall in Suffolk in 1986/87 is against a background of fewer watched sites occupied in eastern England as a whole (January — 1987, 16