Saturday, 12 November 2011

A daylight owl

It has been something of a remarkable autumn, with fantastic numbers of Short-eared Owls arriving in the county from breeding grounds further north. Many of these birds are likely to have made a substantial sea crossing; setting out from Scandinavian breeding grounds their arrival ‘in off the sea’ charted by birdwatchers all along the Norfolk coast. This autumn, there was a report of fifty of these stunning birds arriving at Titchwell in a single day, very much a red-letter occasion for the owl enthusiast.

Short-eared Owls are generally recorded arriving from mid-September onwards, with numbers peaking during October and a few stragglers arriving into the beginning of December. Some will remain on the coast, haunting the grazing marshes, but others move further inland to the fens or the riverside marshes at places like Halvergate and Chedgrave.

These owls are often portrayed as opportunistic wanderers, nomads that track the volatile breeding populations of their favoured small mammal prey. In a good vole season the owls do well and I suspect that this has been one such season. Come the end of summer, however, the small mammal population may sometimes crash, prompting the owls to look further afield for a meal. This combination of a good breeding season followed by a decline in prey abundance may drive the mass arrivals here but there is still a great deal that we do not know about these birds and their movements.

With its piercing eyes, tendency to hunt in daylight and buoyant flight, the Short-eared Owl holds a special place in my affections. Seeing one lifts the spirits on those flat winter days out on the marsh. Seeing several in the air together leaves me grinning from ear to ear! The buoyant flight, a characteristic shared with the Barn Owls that also hunt these wild places, comes about because of the shape of the wings. The broad wings are energetically efficient, allowing the owl to slowly quarter the fields and marshes over which it hunts, while scanning the ground for prey.

Examination of Short-eared Owl pellets – like other owls, Short-eareds cough up the undigestible parts of their prey – reveals that their winter diet in Norfolk is dominated by Field Voles, with other small mammals and small birds making up the balance. These pellets can be collected from the rough vegetation in which these birds roost. Some of the roosts can hold a dozen or more owls, the birds returning to the same site over many days. Knowledge of favoured hunting areas and their accompanying roosts make the Short-eared Owl one of more reliable winter visitors, providing viewing opportunities for the birdwatcher. In cold weather they can be surprisingly approachable (with care), affording stunning views.

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