The future of monarch butterflies has been bleak for the past quarter century, with the decline of eastern monarchs, the world's largest population, declining. However, new data from WWF Mexico indicates that this has stopped, despite threats across their range. The numbers were up this winter, aggregating in trees covering about 7.2 acres of forest in Mexico, up significantly from 4.4 acres the previous year and from 2.2 the year before. Despite this, both eastern and western monarch populations are at historic lows. The crash in US monarch populations is largely due to genetically modified seeds introduced by farmers decades ago. The Obama administration proposed to list monarchs as threatened under the Endangered Species Act, but this has since been rejected.