Friday, January 25, 2013

Short-eared Owl study

There have been up to five wintering Short-eared Owls Asio flammeus on a disused pit top in Gedling, Notts over the past couple of weeks and I had been toying with the idea of a visit for a few days when a phone call from a mate last night gave me the impetus I needed. I arrived at just past 09.00 this morning and there were a number of dog-walkers enjoying the frozen snowy conditions. However, it did not take me long to locate two birds and they provided me ample opportunity to take some photographs.

The Atlas of Wintering Birds in Britain and Ireland published in 1986 by the BTO opens the account of Short-eared Owl thus: 'Floating low down with a wavering and rolling flight, punctuated by occasional glides before banking and wheeling high on stiff narrow wings, the Short-eared Owl provides a welcome winter encounter'.

This is a perfect description of the flight of these two birds this morning. They appeared to be quite tolerant of the dog walkers and me, plus camera but they did not seem to be actively hunting for food.

Both birds frequently landed next to tufts of dead rushes or sedges until eventually both of them settled down out of sight and out of the way of the dogs.
It is known that a variable but frequently large number of these birds arrive from the continent each winter. Arrival can begin as early as late August but most seem to arrive in November. A lot of our own home birds move off to the coast and into mainland Europe so it is possible that the bird on Gedling Pit-top are continental ones.

This site is pretty reliable for wintering Short-eared Owls and as it is known that communal roosts on the ground amongst tall coarse grasses, heather, sedges and scrub are used over many years this site is likely to hold a few of these birds for a few more years to come.

A few years back it was also possible to see up to six birds wintering in the scrub land near to Netherfield Lagoons, just a few miles from this site. I haven't seen any there for some years. Perhaps birds moved from there to the Pit-top which is now the prime site.

Although these birds are opportunistic feeders taking and eating whatever prey they are able to catch their main food item is the field vole and I suspect that there are plenty of these here. However, I shouldn't imagine that thick snow and hard ground would help the Owls' cause much.

The Breeding Atlas says that the mid-winter population of Short-eared Owls is likely to be in the range of 5,000 - 50,000 individuals for Britain and Ireland which is only a tiny fraction of this bird's world population.

The black patches around the distinctively yellow eyes are clear on this individual as is the pale face. The Collins Field Guide says the bird has a 'mean expression'...more quizzical I'd say. Notice the white trailing edge to the wing on this bird - this is a good way to distinguish Short-eared Owl from Long-eared Owl which lacks this feature.

Don't rely on length of ear tufts - short and long - as these are practically invisible in flight in both species. No sign of any tufts on these birds as you can (not) see!

The photo above shows off the very long, narrow and fairly pointed wings and the obviously rounded head. Another good feature by which to tell the two species apart, which is clear in this photo, is the almost solidly black wing-tip with only one clear bar inside the tip. Long-eared have evenly barred wing-tips with several distinct bars. Notice that the belly is un-streaked and the breast is streaked - another good way to distinguish the two species as the Long-eared Owl tends to have the streaking extending over the belly

During the time I was present neither bird made any sound and this is what I have come to expect of this species during the winter. I suppose that if your main hunting technique is to hear your prey it pays to keep silent!



1 comment:

  1. Great shots! It's a good spot for them this year, so it's a case of making the most of the great opportunities while we can!