Legends of the fall: With the return of autumnwatch this month, PHIL GATES investigates the different ways our wildlife copes with this season of dramatic and mysterious change

摘要

Vast flocks of migratory birds on misty mornings, woodlands ablaze with fiery hues and an aroma of leaf mould in the air -autumn has arrived. But what triggers this restlessness in the animal kingdom and the annual display of foliar fireworks? The answer lies in the choreography of the Earth's annual orbit around the sun. Our planet's polar axis is tilted at 23.4 degrees relative to the axis of the sun, so in autumn, when the Earth's northern hemisphere tilts away from the sun's light and heat, northern latitudes experience longer nights and lower temperatures. Soon, the Arctic will freeze, while southern latitudes, tilted towards the sun, will enjoy summer weather.