Experts tell those attending the fourth annual Conservation Partners Roundtable that the aftermath of Blizzard Evelyn could impact spring migration.  A wildlife biologist with the U-S Fish and Wildlife Service spoke to the 90 members at a Thursday meeting in Green Bay.  Gary Van Vreede says birds which normally roost at Lone Tree Island are having to deal with snow and ice this year.  Their nesting could be set back a few weeks.  Additionally, the spawning run for Northern Pike is about two weeks behind the normal schedule.