Migration: Seasonal Movement for Feeding and Breeding

Definition

Migration is the regular, often seasonal, movement of animals from one region or climate to another for feeding, breeding, or both.

Types

• Latitudinal: Birds flying north/south (e.g., Arctic tern, 70,000 km round trip).
• Altitudinal: Mountain animals descending/ascending (e.g., elk, ibex).
• Reproductive: Sea turtles returning to natal beaches; salmon swimming upstream.
• Nomadic/Irruptive: Following unpredictable resources (locusts, snowy owls).

Triggers

Photoperiod, temperature, food availability, hormonal cycles. Navigation uses sun compass, star patterns, magnetic field, olfactory cues.

Human Impact

Barriers (fences, dams, cities), climate change (phenology mismatch), light pollution, hunting threaten migratory species globally.