Spring (March-May) rushes in as the ice and snow melts and the days begin to lengthen. Northern pintails are the sentinels of spring here. When the first drake pintails arrive in late February, spring is around the corner. In some years, winter gives way readily and by March the temperatures are mild and many early season plants begin to green up. Other years, winter hangs on well into April. It is certain, however, that spring will bring many migratory birds to the Refuge that stop to feed and rest before moving on. Some will stay to nest and raise young.