Why do wagtails come to Sprucefield to roost?
by Paul Cormacain
WE have two types of wagtail here one of which is the black and white Pied Wagtail, a common bird of farms.
But as farms become more hygienic the pied wagtail becomes rarer; hygienic sheds, the greatly increased use of more piped water, and more efficiency in insect control, have all contributed to decreased numbers.
Our other wagtail is the Grey, a name which does not do justice to its colourful bright yellow underparts, blue-grey back and long black tail.
It looks like it should be called a yellow wagtail, and in at least one language it translates as 'yellow wagtail', but its official name leaves it' grey'.
Just to complicate things, there is a wagtail which is even more yellow than the grey, and it is called a yellow wagtail. We do not see too many of these here.
The pied is common all over Scotland, England, Wales and Ireland, and is to be found in continental Europe adjacent to the English Channel and North Sea.
It is a sub-species of the white wagtail, a bird whose range extends throughout Europe and North Africa.
The grey is to be found in Scotland, Ireland, Wales, is much less common in England with the bird absent from a huge swathe in the east. It is more common throughout Europe, and may be found close to the coast in North Africa.
The yellow is a sub-species of the blue-headed wagtail, with only a few found in east Wales and south Scotland, and not exactly common over the parts of England where it is found. Other sub-species are to be located over the rest of Europe and North Africa.
A few sightings of yellow wagtails have been recorded in Scotland during the winter period. A handful more came in for England. Summer sightings along the east coast of Ireland have been reported, including in Antrim and the Ards Peninsula.
The chances of seeing one of these birds is, however, quite remote.
There has been a large change in circumstances, with major changes in distribution during the 19th and the first half of the 20th century. One such change occurred up the road at Lough Neagh where a thriving colony of yellow wagtails lived until about 1922.
Numbers started to decrease then, the smaller number of birds was very noticeable by 1932, and there were none by 1942.
A few birds could be found nearby at Lough Beag, but they all disappeared by 1944. Further south there was a similar tale to tell.
A peculiarity of the pied wagtail is its gregariousness in the cold weather.
Many birds roost communally in winter, seeking out warm and safe and sheltered sites. Reed beds are good and popular, likewise low bushes and sewage works.
Other roosts have been reported in large greenhouses. There is another report of the birds using the glass roof of a post office as a mass roost. This was in Leicester.
Internationally, the most famous mass roost is in Dublin, in the trees in O Connell Street, where perhaps a thousand pied wagtails spend the evening.
Now, Rene Boomer tells me of a night roost for wagtails at Sprucefield.
Other birds go in for mass roosts, and in winter our own wrens may pack into a nesting box to huddle together to keep warm.
The wagtails would also be interested in keeping warm, and it is believed that the heat from the lights in O'Connell Street is a factor in their roosting there.
Other considerations are that a dozen or a hundred pair of eyes are more quick at seeing approaching predators than a single pair of eyes.
Then it is believed that hungry birds figure out what birds have full bellies and follow them next morning after leaving the roost, in the expectation of following them to a food supply.
No one has yet actually asked the pied wagtails what is the big attraction in flocking together at night in winter, but the above reasons must be part of the answer.
It would now be interesting to find out how many birds are roosting at Sprucefield, how long they have been there, and do they intend to stay. Must ask them!
Coming Events
Saturday 14 December - Christmas Walk at Mount Stewart, with the Head Gardener, and light refreshments. Why not call 9751 0721
Thursday 26 December - Birdwatch Morning at Castle Espie, 11.30. Contact 91874146 for more.
Thursday 26 December - Monday 7 January - Follow the Robin Trail around Castle Espie. Fresh air, exercise, bird spotting, and you can walk off your excessive Christmas meals. Phone 91874146
Ulster Star
13/12/2002
