One of the things that has always fascinated me has been bird migration – and how they find their way over thousands of kilometres of land and ocean. Some birds are born knowing; others learn from their family group – common in big birds like geese. They memorise landmarks such as rivers — or nowadays motorways! Birds have been noted to follow the M3 up from the south, then turn onto the A25 to circle London until they get to the M1, where they peel off again, heading north. I’m not kidding.

And now there’s been some fascinating work on birds and magnetic fields:

Birds use their right eye to see the Earth’s magnetic field and use it to navigate, scientists have discovered.

German researchers found that if a bird’s right eye was covered by a frosted goggle, the birds could not navigate effectively, while they could navigate perfectly well if the left eye was covered instead.
It has long been known that birds are able to sense magnetic fields and use them to navigate, particularly when migrating south for the winter. Snow geese head off on the migratory journey: Scientists have found that birds can actually see magnetic fields…

See the whole article here.Unfortunately, it is rather badly explained, but interesting nonetheless.

The funnel-like cage they are talking about is called an Emlen funnel. Usually it has an ink pad on the base and sloping walls. When a bird is ready to migrate, it faces the way it wants to go — and leaves inky footprints on one part of the side wall, but not on the others. So never fear, they didn’t have to release the birds wearing the goggles to find out whether they would go the right way!!

(Competition results later today. Still time to enter..)

With improved battery technology, there has been some success recently in tracking migratory waders. Here’s the journey of a little lady unromantically called Bar-tailed Godwit N7. [She stands maybe nine inches (22 cm) tall – that beak is 3.4″ (8.6 cm) long.]

She had a summer holiday in New Zealand. I mean, who wouldn’t want that, when the alternative is spending the winter up in Alaska? She was fitted with a satellite transmitter while there, which apparently didn’t trouble her, because in March she popped over to China, near the Korean border, for 5 weeks rest and gourmet dining. A New Zealand to China non-stop flight lasting a mere 7 and a half days, travelling at an average speed of 56 kph (34.7 mph). No wonder she was hungry enough to stay 5 weeks enjoying Chinese food.

She then travelled on to Alaska, probably for some sex and family time. She stayed a couple of months, but winter doesn’t look too good in that part of the world, so she headed off to New Zealand again at the end of August. More or less south. She doesn’t think much of Hawaii or Fiji apparently, because she declined to stop. Nothing like non-stop flights…for 8 and a half days.

She’s now back in New Zealand. Having flown over 29,000 kms (18,000 miles) this year – or 500 hours of flying time. Pity she can’t sign up for a frequent flier programme…
…and I have the cheek to complained about 37 hours to get back to Kuala Lumpur from USA? And I didn’t have to flap my arms, either.

Photo courtesy of Ooi Beng Yean, one of Malaysia’s most talented bird digiscopers. Please do not use without permission from him.