Lesser Scaup in north Cumbria: new to Cumbria    Spring 2003

Late morning on 12th January 2003 Margaret and I were walking along a familiar path through Low House Wood, on the west side of the gorge of the River Eden, north of Armathwaite. We often use this path for ‘constitutional’ purposes, as it passes through good scenery, and sometimes attracts a nice selection of birds.

As we reached a particular bend, where the outflow from a Holmwrangle fish hatchery on the opposite bank seems to cause local enrichment and enhanced food-supply in the river, we spotted a group of Tufted Ducks in the river – a quite normal occurrence here at any time of year. In winter the spot attracts Goosanders, Goldeneyes and sometimes other species. (In September 1991 I had a probable drake Canvasback here, also seen by Roy Atkins; frustratingly on that occasion we did not get sufficiently good views for the record to be confirmed.)

A scan of the Tufties also revealed another small Aythya, with whitish sides, a rather dark-grey-looking back, and a somewhat triangular head-shape. From what I could see, it struck me that this looked just like a drake Lesser Scaup – or perhaps a very clever imitation of a Lesser Scaup by one of those mimicking hybrids.

At this time the sky was heavily overcast, and overhanging trees were making observation tricky. Rather than attempting a closer view at this stage, several circumstances dictated a retreat: I was carrying neither telescope, field-notebook, nor mobile ’phone; the group of birds looked distinctly flighty; my recollection was poor of just what features would have to be recorded to distinguish Lesser Scaup from the look-alike hybrids; and there was the pressing need to try to get other observers to see the bird. (I knew that it would be a new county record if confirmed – and I was certain enough from the views obtained so far that it would prove to be a Lesser Scaup. Substant­iation was therefore imperative.)

We returned home, and I contacted a number of local and more distant observers, read up as much as I could find in the literature to hand on the hybrid problem, and grabbed a ’scope. I was back in place within an hour or so. A number of others observers had beaten me to it, but of the putative Lesser Scaup there was no sign! Frustration! Searches of nearby stretches of river proved negative, and most people dispersed – myself included.

Thankfully – and all credit to him! – Colin Raven had persisted, and he later re-located the bird, with a few Tufted Ducks, a few hundred yards downstream (just beyond where I had earlier searched). He phoned me during the evening with the news of his find, and to confirm that he was happy that the bird was a Lesser Scaup. Frustration turned to elation – but would the bird remain around?

At about 12.30pm, three Aythya ducks flew in, and dropped nearby, soon joining up with the group of roosting ducks. These proved to be two Tufteds and, remarkably, a female Greater Scaup, enabling those still present to compare the two Scaup species together.

The next morning, after heavy overnight rain, the river had risen considerably, and I saw no Aythya ducks.

A Lesser Scaup was next reported to the birdlines (although I do not know by whom) on 16th January, six kilometres north-northeast at Castle Carrock Reservoir, but on 17th January, it could not be found there, nor on the river, nor on nearby Talkin Tarn.

However, a Lesser Scaup – presumed on plumage features to be the same bird as the original sighting – was found early on the morning of the 18th at Talkin Tarn, near Brampton, four kilometres north from Castle Carrock Reservoir. It was seen on the tarn intermittently thereafter, to at least 20th February, enabling many other observers to catch up with the bird, in much better conditions, and often much closer.

The bird fed extensively by diving, often alone, moving widely about the tarn. During this spell, parts of the tarn froze over, and when present the Lesser Scaup would often dive right at the ice edge, as if it was foraging below the ice. When roosting, it associated at times with numbers of Tufted Ducks and the few Pochards also present, but also joined roosting Mallards, or roosted alone. At best, the bird was seen in sunshine, and at ranges down to about 40 yards or less. Many photos were taken by various photographers, and digital versions soon began to appear on the websites.

Its size was very similar to nearby Tufted Ducks, and its overall shape and behaviour more reminiscent of this species than of Greater Scaup. The body outline was however different: while Tufteds had a smoothly curved back, the Lesser Scaup’s back was highest at a point close to the front, and sloped away from this ‘hump’ in quite a smooth line towards the tail.

The forehead was rather sloping, rising to a high, peaked crown, with a slight rearwards-point­ing ‘bump‘ on the upper-rear of the crown, varying in distinctness on different occasions. The back of the crown/nape was fractionally flatter than the more smoothly rounded Tufted head. The head-shape looked overall rather ‘triangular’, and this aided locating the bird at a distance.

The bill was much like a Tufted’s in shape. In colour the bill was pale ash-grey, but with slightly darker grey ‘smudges’ on the ridge and below the nostrils. Importantly, the nail was black, and when seen directly in front view, could be seen to be parallel-sided, and longer (front-to-back) than wide. The black of the nail did not extend sideways onto the rest of the bill.

There was some disagreement amongst observers as to the colour of the iris. Certainly it was not bright yellow, as were the irides in the male and female Tufteds; I wrote it down as ‘dull yellowish’. In brighter conditions, it looked more clearly yellow – perhaps a result of a reduced pupil size in bright light, so showing a larger area of iris.

The head was black, with a sheen, appearing green or purple depending on the angle, at least to my eyes. The neck was black.

Feathers of the mantle, back and scapulars were strongly vermiculated, with dark lines on a whitish background; the effect at a distance was quite dark, and contrasted markedly with the much paler, whitish, flanks. The dark vermiculations were fine and close together on the mantle, and became coarser and darker rearwards onto the scapulars. The rearmost scapulars were ‘smudgier’ and the vermiculations less clear. Tertials were relatively unmarked sooty-brown.

(Although I twice saw it in flight, with Tufteds, on 13th January, I personally did not make out much of any value in the flight-pattern, to distinguish it from Tufted Duck, in the dull conditions.)

Some mottled brown feathers at the forward edge of the mantle, some brown-tipped flank- and breast-feathers, and perhaps the sooty-brown tertials, appeared to be retained juvenile feathers (rather than retained eclipse feathers), making this bird a first-winter individual. (However, some observers who had seen the Auchenreoch/Milton birds, mentioned below, expressed surprise at how far advanced its moult was towards maturity, compared to those birds.)

In all respects, this bird appears to have been a typical Lesser Scaup. In particular, the precise patterning of the bill and the coarseness of the black vermiculations on the upperpart feathers helped to confirm the identification, and rule out the similar hybrids (especially Tufted Duck × Pochard). Although the colour of the head-sheen is sometimes given as a character, recent books such as Sibley’s North American Bird Guide confirm that scaups of either species can show green or purple in different conditions.

Two immature drake Lesser Scaups appeared on Auchenreoch Loch, at Crocketford, west of Dumfries, on 20th December 2002 (remarkably, the same site as the UK’s fourth confirmed Lesser Scaup in January 1991), with a third being found there the next day. Two of these still remained at the time of writing (early March) either at Auchenreoch or at nearby Milton Loch (reportedly with a look-alike hybrid also present), but the third Lesser Scaup was apparently not seen after 24th December. It therefore seems possible that the Cumbrian bird was one of those three, since the appearance of ‘our‘ bird post-dated the disappearance of one of those Scottish birds.

Some of these vagrant American ducks – once on ‘this’ side of the Atlantic – tend to remain (though some do make a successful return across the Atlantic, as has been proved by ringing), and, although probably migrating north and south, may return to areas where they have previously successfully wintered. Thus it may very well be worth keeping an eye open for this engaging little curiosity in future seasons.

I am grateful to Ronnie Irving for permission to include photos taken at Talkin Tarn on 15th February. Colour versions are available on the CBC website. I am also grateful to various respondents to my queries on the BirdingCumbria e-mailing list for clarification of dates.

The record has been submitted to BBRC.

Jeremy Roberts