AVOCETS O N THE MINSMERE
SCRAPE
H . E . AXELL
IN April, 1947, after the species had not been known to have nested successfully in Britain for about 100 years, four pairs of avocets were found at Minsmere and in July of the same year another four pairs were discovered nesting on nearby Havergate Island. A total of 16 young was fledged from both sites (Brown, 1950). The Havergate colony increased steadily though with variable breeding success each year after 1948, when the island was purchased by the R.S.P.B, and water levels were maintained. At Minsmere, where, in common with other East Anglian marshes the Level had been flooded as a war-time defence measure, the good conditions for avocets were created as the water was lowered when hostilities ceased. The potential of the new marshland for a variety of wet-land birds was quickly seen by Geoffrey Dent of the R.S.P.B. Council and a new reserve of 1,500 acres was leased from the landlord, the late Stuart Ogilvie, in 1948. Avocets returned to Minsmere in that year but no breeding took place because the site had become unsuitable, mainly through the spreading of reed. The birds did not resume breeding at Minsmere until 1963, a year after the construction of the Scrape was begun. As an original conception of habitat manipulation, the Minsmere Scrape was planned principally with the object of providing a safer nesting and feeding environment for some of the birds whose existence on beaches and estuaries was becoming increasingly affected by human activity. Essentially a shallow, brackishwater mere dotted with islands, it was excavated from a dry section of the Minsmere marsh which previously had had little ornithological value. Work with a bulldozer was begun early in 1962 and the new mere was extended to cover nearly 50 acres, in annual stages after each breeding season, by 1973. Most of the 50 islands were topped with gravel, obtained from inland deposits, a membrane of polythene being under-laid to prevent the growth of tall plants like reed and creeping thistle. Within five years, 1,500 pairs of birds of some 20 species were breeding in an area where previously only about 40 pairs had bred each year (Axell, 1973). The growth of the avocet colony in association with other species is given in the Table where a consistently high annual fledging rate of two per pair is shown to have been possible under the mainly controlled conditions. Avocets, like most waders, do not bring food to their young but rigorously resist competition from other birds in the best available feeding territories. Fledging success is therefore largely dependent upon the quality and