WATERBIRDS DISPOSSESSED — Marshes, swamps and wetlands throughout the United States are on their way out. Going with them are hundreds of our waterbirds. Ducks, geese, herons, grebes, coots and many other birds that depend on wetlands for nesting, shelter and food are being dispossessed. As water and land are being taken over for farming, industrial development or to give expanding cities room, whole populations of waterbirds are disappearing, many going north and south of the border. Three scientists, studying a small marsh in Utah, have been able to measure the direct effects of lost wetlands on waterbird populations. Of 17 species found nesting or living in the marsh in 1950, six did not nest there at all in 1955; four species were still around but had two-thirds fewer nests, while nests of the other species were also present in reduced numbers.