The Monarchs' Migration
Like many birds, monarch butterflies migrate south for the winter. They’re not able to survive winters in the US.
Plus, the plant the caterpillar feeds on – milkweed – is not available to them in the winter.
So every fall – in early October, huge clouds of monarch butterflies make the 2,500-mile trek south where they live in hibernation for six to eight months. Then, in February or March, the entire cycle starts all over again.
Most Monarchs spend the winter in Mexico where they have the uncanny ability to find the same Oyamel fir tree where generations before it spent their winters. If Monarchs live west of the Rockies, they migrate to Pacific Grove, California where it hibernates in eucalyptus trees.
The monarch butterfly is one of a few known insects that migrates to warmer climates. It’s a remarkable journey that is now threatened by the loss of the monarch caterpillars’ main source of food: the milkweed plant.
The monarch’s winter home is also threatened because many acres of the Oyamel trees in Mexico are being cut down by illegal harvesting of the forest.
The Monarch Miracle
The monarch butterfly is an incredible creature that starts as an egg and goes through three amazing transformations during its life.
The egg hatches into a caterpillar, which forms a pupa (chrysalis), which is then transformed into the adult butterfly.
In February or March, the monarch emerges from hibernation and finds a mate. It then migrates north and east and finds a milkweed plant on which to lay its eggs – usually around March or April.
It usually takes about four days for these eggs to hatch into baby caterpillars, which become virtual eating machines, consuming large amounts of the milkweed leaves
After two weeks, the full-grown caterpillar finds a place to attach itself and begins the process of metamorphosis. The monarch butterfly emerges from the chrysalis after about ten days. The full grown butterfly only lives about two to six weeks, during which time it finds a mate and lays its eggs, beginning the life cycle all over again.