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Show DDT Drenched Trees Kill Off the Birds After its elm trees were sprayed with the insecticide DDT j to destroy elm bark beetles, the Michigan State University "North Campus" at East Lansing became a death drap for many more robins that were ever resident resi-dent on the 185-acre area. This is the import of an article by Dr. George J. Wallace, faculty member of the university's zoology zo-ology department, published in a recent issue of Audubon Magazine. Maga-zine. In an earlier article, published in the January-February 1959 issue. Dr. Wallace had described the decline of resident robins on the campus from an estimated 185 pairs in 1954 to few or no resident birds by the summer of 1958. Studies by Dr. Wallace and his research assistants during 1959 disclosed a presistent influx from surrounding areas as the birds attempted to repopulate vacant nesting sites and feed on the campus lawns. Specimens and reports of dead and dying robins, believed to have been poisoned by feeding on DDT-laden earthworms, earth-worms, also continued to flow in. "These data" Dr. Wallace wrote, "verify what we surmised in 1958, but were unable to measure meas-ure precisely namely that the total loss of robins in a situation like this may be several times greater than the entire population popula-tion present at any one time. In essence this means the more or less complete elimination of the original breeding population, plus one more replacement populations. pop-ulations. These data also show that the continued presence of robins on a given area is no proof that high losses have not been sustained, or that the losses are inconsequential." |