SHOREBIRD COUNTS IN THE DUTCH WADDEN SEA, 1980-91 - A COMPARISON WITHTHE 1965-77 PERIOD

Between 1980 and 1991 36 counts were carried out of all birds which ar e ecologically dependent on the Wadden Sea. The results are compared w ith those from the 1965-77 period, using counted figures and additiona l estimated data for areas which were not included in the surveys. An obvious increase can be noted for brent goose, corresponding with the fourfold increase in population size over the last 20 years, oystercat cher and grey plover. A decrease can be noted for teal and August and September numbers in knot. Numbers have also gone up for shelduck, mal lard, pintail, bar-tailed godwit, curlew, spotted redshank, redshank, black-headed gull, common gull, and herring gull, but not as evident a s in the first three species. An assessment of the Dutch data shows th at bird numbers and densities are very comparable with those from else where in the international Wadden Sea area. This does not apply for th e January-April period when numbers are higher. This is due to the mil der weather situation in the western part of the Wadden Sea.