20 August 2012

Airborne christening party

How do birds learn to fly?

Or, more specifically, how do the aerial nest-builders manage it?

I have an image of a baby sparrow gradually emerging from a nest and learning the basics.  You know, fluffing up feathers, eyeing the world and then a few exploratory wing flaps before a short tentative hop to a lower branch.

But what happens to birds like house martins, facing everything from a dizzy 30ft under the eaves, and no perch nearby? 

We’ve been pondering this as we watched the antics of two families who have built nests high up on the walls of our house.  And, like many parents, we wondered when the young might leave home.  And, in this case, how. 

Today we learned much more about such behaviour, and it was quite a moving and uplifting experience.

At just after 8am, the air to the side of our house became peppered with house martins flying repeatedly up towards the nest.  We could also see the tiny head of the fledging poking out.  This was the day, the martins had clearly decided, that the young bird would begin to fly.    

Round and round they swooped, perhaps a couple of dozen or more of them.  They were clearly demonstrating, “This is what you do.  Come out and join us.”   They kept circling and then, so quickly that Annie actually missed it, the fledgling tumbled out of the mud nest and seemingly effortlessly (although it might not have seemed like that to the young bird) swooped over the garage and was gone. 

It was, as Annie said, an airborne christening party.

What reflexes do the birds rely on to decide that this was the day for flight?  And how do they communicate to act so collaboratively in encouraging the youngster? 

It might be corny, but we have so much to learn about, and from, the world around us.      


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30 January 2007

Swoop Club

Every winter's evening, starlings flock to roost in the reedbeds of the Somerset Levels. Nothing unusual about birds roosting except, in this case, the numbers involved. It is said that about 3 million gather at dusk, swirling and swooping over a large nature reserve between Glastonbury and Bridgwater.

We went to view the spectacle on a clear and windless evening. It really is a sight you have to experience, as it is impossible to give an accurate sense of it in words.

Imagine the sky being thick with black dots, suddenly dimming the light as they pass overhead. Think of the whoosh of hundreds of thousands of wings beating simultaneously. Hear the sound of a million or two starlings chattering together, once they have settled in trees or on reeds.

It is an amazing experience, and one that is perhaps not publicised extensively for fear of the effect of an overwhelming increase in visitors. For the location is deep in the Levels, reached along bumpy single-track drove roads with a completely inadequate single car park at the reserve.

The event starts with the arrival of the first thin lines of birds. Then it quickly builds up, with massive flocks arriving from all directions, and merging together to form giant fluid helix patterns in the sky. The starlings' aerial flightpaths all seem locked on this one location. We wondered how far some had come.

The birds gather to provide commual warmth and protection from predators. Then in the morning, the daily commute starts back to their day-time haunts.

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