Thursday, 19 December 2013

I have been watching out for the Pied Wagtails as the weather gets colder. They have been roosting, at least for the last couple of years, in the trees at London Heathrow’s Terminal 5.

This year the maintenance contractors at the airport gave the trees a severe pruning and I wondered if the wagtails would still find it an attractive place to roost. They had shown a marked preference for the thinnest of branches, but the trees had been reduced to stumps by enthusiastic loppers.

A few whippy branches remain on the trees and the birds have returned. I first noticed them on December 12th. I had associated the arrival of the birds with temperatures well below zero, but this year they have appeared before the extreme cold snap.

There are enough whippy branches left on the trees to give roosting room for a flock of 1000 plus wagtails, but I wonder if that is as many as we have seen in the previous years. Perhaps it will build as the weather gets colder and the flock will spill over into the next stand of trees if the roosting room runs out.
Someone suggested that the contractors had done a shoddy job, but I prefer to think that the few, thin roosting branches were left by a considerate tree surgeon with the wagtails in mind.

If you wish to see the local form of the White Wagtail, they roost outside London Heathrow’s Terminal 5 at the southern end of the building in the sheltered trees at Google Earth ref; 51 28 14.52N 0 29 21.66. They come in from the surrounding area around dusk and stay until the early light. The terminal buildings give them protection on all sides and must be a relief from the cold on the bitterest of nights.