House Martin Migration

18 September 2019 | Posted in Charlotte Owen , Birds
House Martin Migration
House Martins © Derek Middleton

By Charlotte Owen

WildCall Officer

September is a month of transition.  As we all headed back to school and back to work, our wild summer visitors are heading back south.  Their work here is done and they now face a long-haul flight to the warmth of their wintering grounds.

Some have already left.  Our screaming swifts departed in mid-July, eager to be off as soon as their families had fledged.  They will be in central Africa or beyond by now but some of our best-known migrant birds linger here for longer.  Swallows, sand martins and house martins are known as hirundines, a group of small and elegant aerial acrobats with long, swept back wings and forked tails.  Swifts share many of these features but despite appearances, they are not closely related.

Swallows and martins spend their late-summer days feeding up on flying insects as they edge ever closer to the coastline.  Swallows are famous for gathering on telegraph wires but they can also be seen in huge numbers flying over lakes and wetlands in a chaotic feeding frenzy, hoovering up the last of the midges and wreaking havoc for any other birds that enter their airspace.  They often form mixed flocks with house martins but can be tricky to tell apart in flight.  Probably the easiest feature to look out for is the swallow’s much longer, plumed tail. 

As time goes on, the soon-to-be travellers get increasingly anxious as they enter a pre-flight condition known by the German word zugunruhe, meaning migration restlessness.  Even captive birds experience this, jumping about their enclosures and fluttering their wings as the urge to begin their voyage becomes ever stronger.  It is a deep and irresistible instinct like a pre-programmed flight plan, urging the birds to leave when the time is right and driving them to continue their epic journey until they reach their destination some 6,000 miles from here, sunning themselves in South Africa while we endure a British winter.

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