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Why migrate?

Key facts

Animals migrate for some very simple reasons:

  • Food
  • Sex
  • Space
  • Sunshine

Latest Reports

Latest Comments

"Ddo you have a migration theme on tigers?"

Daniel McIver

Get in touch if you've got any comments or questions on the Why migrate?.

Invasion of the Crossbills

Many birds migrate because it’s “in their genes” but the Crossbill has evolved to undertake similar feats of stamina in response to their environment.

This year Crossbills invaded parts of the UK where they’re not usually seen.

Themes information

Animals mostly migrate for sex, space and sunshine - to reach breeding grounds and enjoy a climate where food is plentiful.

Some animals make journeys that are so long there's a good chance they won't make it, so the payback - the advantage gained - must be high too. We'll be exploring the risks and paybacks in our programmes and you can follow the story as it unfolds.

The swallows which raise chicks in our barns and outbuildings come to the UK for the plentiful breeding sites and insects. When the colder autumn weather arrives, they head for the warmth of South Africa, where there is plentiful food for them, an extraordinary journey which includes crossing the hot dry Sahara Desert.

The Atlantic salmon swims thousands of kilometres to breed in the exact river where it was spawned (we'll be studying salmon in the Tyne). Its movements are so well known to predators, including anglers, that only a small proportion complete the journey.

Brent geese fly to the Arctic tundra in time to breed and hatch young which feed on the grasses and insects that abound in the long days of an Arctic summer. The geese return to the milder climate of the UK as temperatures plummet.

There is clearly a biological advantage in being able to exploit different areas at different times of year, and a real risk in making the journeys. Find out more by following the "reasons why" stories from our reporters in the field.

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