From Birding Scotland 2(4), pp. 165-167.
There was a small roost of terns, gulls and waders on the rocks at the north end of Thorntonloch beach as my son and I walked down from the concrete walkway at Torness Power Station (Lothian). It was 11.10 a.m. on 9th August 1999, and with huge waves crashing behind them, the birds were obviously gaining some shelter from the fierce, north-easterly wind. We were too, so I took the opportunity to scan through the group. At a range of only 75 m a large, orange-billed tern on the edge of the roost stood out like the proverbial sore thumb. During the following rush of adrenaline, I hastily persuaded my five-year-old son that he would have to occupy himself for "a while" (which he thankfully did) and I sat down to study the bird for 40 minutes before we had to leave. The tide was rising rapidly and the rocks would have been completely covered soon after.
During the next couple of hours, Colin Davison and I checked numerous places between Thorntonloch and Belhaven trying to relocate it, but the tide was very high and there were few roosting terns anywhere. Amazingly, it appears that the bird had flown directly to Musselburgh, because by a stroke of luck, John Pringle saw it on the Musselburgh scrape at 3.45 p.m. for 1-2 minutes before it was flushed by a workman.
When news of that sighting eventually filtered out, the search effort quickly moved to Musselburgh. At 6.55 p.m. Dave Allan relocated the bird on Fisherrow Sands, news was phoned out and thankfully it remained long enough for c.75 birders to see it. At 8.10 it took off and headed east, but it was later seen plunge-diving off the lagoons, and it returned to the tern roost at 9 o'clock. It was still present when it got dark at 9.45, and in the last stages of dusk, those who had dashed from Aberdeen, Ayrshire and Newcastle managed to get a view.
Some 400 searchers had a frustrating day the next day, as despite the understandable optimism that it would stay, it could not be found anywhere between Blackness and Thorntonloch, or in Fife. Royal Terns had again lived up to their reputation as one-day birds.
Salient features
This bird was clearly big, and this feature alone pointed to it being a Royal Tern. It was at least 15-20% larger than Sandwich Tern, as well as being deeper and broader chested. It stood head and shoulders above the Sandwich Terns, and was comparable in size to a Common Gull, although not as bulky in the body. Some problematical birds in the past have been only marginally larger than Sandwich Terns, but this one was BIG.
The bill was a bright mid-orange, but more yellowish towards the tip. It was disproportionately long and heavy; much larger than a Sandwich Tern's even when allowing for its pale colour and the larger size of the bird. It was deep based, the upper mandible was noticeably decurved and there was a slight gonydeal angle on the lower mandible. The length of the bill was comparable to the distance from the bill to the back of the head.
The bird was moulting into winter plumage, with the forehead being white, the crown well flecked with black and the shaggy crest black with white flecks. The black enclosed the eye, unlike in full winter plumage when the eye becomes surrounded by white.
The colour of the mantle and upperwings was pale grey. In direct comparison with Sandwich Tern, it was the same shade (in brighter light) or perhaps slightly paler (in dull light).
At rest and in flight, the outermost primaries were seen to be worn and dark grey in colour contrasting with the inner primaries which were fresh and a paler, mid-grey with narrow white fringes. The rest of the upperwing was pale grey, except for a small dark mark on the inner secondaries formed by 2-4 darker centered feathers. The rump was not pure white, but had a pale grey wash rather than being concolorous with the mantle.
Its flight jizz was very distinct - it appeared ghostly pale with long, broad-based wings and deeper wing beats (compared with Sandwich Tern). The wings were also not held as angled as Sandwich Tern.
Discussion
I identified the bird as a Royal Tern, as opposed to a Lesser Crested, Elegant or Caspian Tern, on the basis of its size, bill shape/size, mantle colour and rump colour. Although an inexplicable loss of concentration had lead to its initial identification as a Lesser Crested Tern, this was corrected instantly I had the opportunity to consult the new Collins Field Guide and remind myself that Royal Terns existed!
The overall large size of the bird may suggest it was an American race bird, but the very pale mantle colour together with rather long bill with indistinct gonydeal angle indicate it was perhaps more likely to be a West African bird, possibly a large male.
This is only the fifth British record, and the first for Scotland. The previous records, all in the south, are:
1965: adult Sandwich Bay (Kent) 28-29 July (British Birds 61, 559-561)
1971: St Ives (Cornwall) 2 September
1979: 1st-winter (with ring) Kenfig Pool (Mid Glamorgan) 24 November (British Birds 76, 335-339)
1987: 1st-winter (with ring) Mumbles, Swansea (West Glamorgan) 21 December
Other Western Palearctic sightings, away from North Africa:
Ireland: one long dead North Bull, Dublin 24 March 1954 (British Birds 48, 116-117)
Spain & Gibraltar: 10+ records between 1970 and c.1990
Norway: one June 1976
[In addition, there are several other records of large, orange-billed terns that have been accepted as either Royal or Lesser Crested Tern:
1982: Dungeness (Kent) 26 June
1984: Folkestone (Kent) 17 September
1989: Gibraltar Point (Lincolnshire) 30 May]
This was the latest in a string of records that have recently put Thorntonloch firmly on the birder's map, adding further to the list of East Lothian coastal sites that cry out for better coverage. And yet again Musselburgh lives up to its "awesome reputation" (British Birds 89, 490) and confirms itself as a (if not "the") premier birding site in Scotland! To mention just the terns, it has now hosted one Royal, two Lesser Crested and two Forster's Terns. But the future of the all-important roost site at Musselburgh is far from secure. If you value Musselburgh as a birding site, why not lobby East Lothian Council to enhance the habitats at the lagoons, before the scrape becomes a mere oasis in a sea of grass.