Monarchs will migrate every year approximately 2500-3000 miles from Canada to Mexico where they will over-winter. Their average life span can be 4-6 weeks except the last generation of the year where monarchs can live 8-9 months. The amazing part of their migration is they return to the same location even the same trees in Mexico, year after year! So, along their journey they need food and the ability to lay eggs. The larvae will only eat milkweed. The best Milkweed to plant for them: Swamp Milkweed, Common Milkweed, Butterflyweed, or Showy milkweed.