Here are 12 fascinating facts about the migration of UK garden birds:
1. Not all birds migrate for the winter, some like the Chaffinch stay here in the UK all year round.
2. At least 4,000 species of birds migrate. This is about 40% of the total world population.
3. Nearly 17 million birds pass through the UK during their migration, either passing through or staying for the winter or summer months.
4. Decreasing daylight hours and other external factors like temperature can trigger a hormonal reaction in birds telling them to migrate.
5. Birds need to eat as much as possible to ensure they survive the migration journey. Some almost double their weight before they leave!
6. Sparrows, Wrens and many other songbirds migrate at night as there is less risk of dehydration and it’s a smoother ride, as there is no hot air rising from the ground.
7. It is thought that birds get their directions from the location of the setting sun and the stars in the sky. Some think birds can even pick up on the earth’s magnetic field to help them navigate!
8. Organisations such as the BTO track the migration of thousands of birds each year to plot migration patterns and determine how and why they are changing.
9. Humans can have an impact on migration patterns. Through its tracking, the BTO have spotted that Blackcaps have shifted its migration to the UK to make the most of bird feeders left out in our gardens.
10. Scientists from the University of Oxford have discovered birds use the v-formation to save energy. They take it in turns to do the difficult task of leading and then the others save up to 20% of their energy by travelling in the updraft wind tunnel behind. Find out more about this research.
11. A staggering total of 35% of young birds can die during their first migration. However, this leads to survival of the fittest which ensures bird populations stay healthy and fit.
12. Some birds fly for several days non-stop while migrating and have developed the ability to fall into a light sleep whilst they are flying.