Pomarine Skua at Lower Foulridge Reservoir, Lancashire, UK.

 28-29.11.1999. - by Peter Hornby.

I was on the NNE side of the reservoir at 09.15hrs, when a very dark brown, medium sized bird came into view, flying low over the water about 50yrds away.

Almost immediately, it literally dropped onto a 1stw Black-headed Gull which was on the water, facing away from it. The bird then submerged the B.H. Gull and pecked at it's head in order to kill it.

I realised that it was a Skua!

The wind was blowing onshore, so that during the few minutes the Skua took to overwhelm the Gull, it had drifted onto the shore only 15yrds away from me, where it plucked the now dead Gull and began to eat it.

At this range, I was able to observe all its features; it was clearly a juvenile.

As it continued to eat the Gull, I walked round the reservoir and borrowed a fishermans mobile phone to alert local Colne birder Harry Magill (HM) and the ELOC telephone tree. I then returned to the Skua, which was still feeding.

HM quickly arrived and we were joined later by Alan Baldwin and Bill Duerden.

The Skua continued to feed (at one point when two Carrion Crows approached, the Skua would push them several yards away whenever they came to close) until just before 11.00hrs, when having completed it's meal, it briefly washed before flying out over the reservoir, and, after several circuits, drifted away to the north at 11.05hrs.

I was fairly sure by this time that the bird was a Pomarine Skua (Stercorarius pomarinus) and upon returning to HM's car, we checked the finer points in 'Lars Jonssons field guide' which confirmed them to be consistant with a juvenile of that species.

The bird re-appeared later and continued to show well for the remainder of the day, giving prolonged, close views as it sat in a field adj to the reservoir, allowing most east lancs birders to see it.

The bird remained until 12.30hrs the next day (29th November), when it was seen to fly west.

I subsequently heard from fishermen, that it flew past them close inshore at times and on one occasion, it briefly came even closer as it followed a baited line being reeled in.

Description.

Head - A uniform dark medium brown, slightly darker around the eyes.

Mantle, Scapulars, Coverts and Tertials - Very dark brown, almost black ground colour with orange-tinged, buff and slightly broken, wavy-edged fringes.

Primaries - Same very dark brown colour as back, but with no pale fringes.

Rump and Uppertail Coverts - Same very dark brown colour as back, with a restricted area of fairly broad barring in orange-tinged buff.

Tail - Same uniform, very dark brown colour as back, but with no pale fringes. When spread in flight, square-ended, with no discernable central projection.

Chin, Throat & Upper Breast - Dark brown, but slightly paler than head.

Lower Breast & Belly - Dark brown, but becoming slightly paler towards the vent, with initally narrow, paler brown barring, becoming progressively broader.

Vent & Undertail Coverts - Medium brown, interspersed with bold barring, which was a medium cream/buff colour in the vent area, becoming paler on the undertail coverts.

Eyes - Small in proportion to headsize, almost the same dark brown colour as the head.

Bill - Fairly long in proportion to the head, not quite as heavy and broad as I expected at close quarters (perhaps a subjective impression?). The basal area extending approximately three-quarters along was pale grey, slightly horn-tinged, making the tone slightly duller than the leg colour. The final quarter was black-tipped with a very finely hooked upper mandible.

Legs & Feet - Very pale grey legs, contrasting sharpely with black feet.

Wings in flight - Arms of wings very broad, then narrowing from carpal joint to wing-tips. Upperwings: secondaries slightly paler than the very dark primaries (presumed due to pale feather edges in former areas). Pale feather shafts of dark brown outer primaries forming prominent white wing flashes. underwings: secondaries paler than body, with interspersed pale and dark feathering, giving a slightly patterned 'tramline' effect. The primaries were even paler, giving a diffuse, white wing patch.

Size comparison - On the ground, it was slightly bigger and more sturdily built than the Carrion Crows. In flight, it appeared similar in size and had a similar bulky structure to Lesser Black Backed Gulls and Herring gulls, which were visible in the same field of view.