Anderson D W, Jehl J R, Risebrough R W, Woods L A, Deweese L R, Edgecomb W G
Science. 1975 Nov 21;190(4216):806-8. doi: 10.1126/science.1239078.
Although still about 30 percent too low for population stability, productivity of California brown pelicans at their two northern colonies has improved significantly since 1971. Numbers of adults breeding probably reflect food supplies and recruitment from more successful colonies to the south, but improving fledging rates (up to 0.9 young per nest in 1974) reflect better egg survival and improving eggshell condition, with declining DDE contamination in anchovies, their major food source.
尽管加利福尼亚褐鹈鹕在其两个北部繁殖地的繁殖率仍比维持种群稳定所需水平低约30%,但自1971年以来已有显著提高。成年鹈鹕的繁殖数量可能反映了食物供应情况以及从南方繁殖更为成功的栖息地迁来的补充数量,但雏鸟成活率的提高(1974年达到每窝0.9只幼鸟)反映出更好的卵存活率和蛋壳状况改善,同时其主要食物来源凤尾鱼体内的滴滴伊污染程度在下降。