Final answer:
Monarchs migrate once a year from their breeding grounds in the US and Canada to Mexico to escape winter conditions. The decline in monarch numbers is due to habitat loss caused by deforestation, agricultural practices, and urbanization.
Step-by-step explanation:
Monarch Migration
 Monarchs migrate once a year from their summer breeding grounds in the United States and Canada to their wintering grounds in central Mexico.
 Migration Reasons
 The primary reason monarchs migrate is to escape the harsh winter conditions of their breeding grounds.
 Migration Route
 They follow specific routes called flyways, traveling thousands of miles to reach their overwintering sites in Mexico.
 Decline in Monarch Numbers
 The numbers of monarchs are dropping due to multiple reasons, such as loss of milkweed plants (which are vital for food and reproduction), loss of habitat, climate change, and pesticide use.
 Threats to Habitat Loss:
 - Deforestation
- Agricultural practices
- Urbanization
Learn more about Monarch Migration