Found by: J. Martin.

Introduction

On November 16th at about 11:30 I stopped off on my way to do my WeBS count to look at the flock of gulls loafing in a field of winter wheat next to Harnhill Tip, Elberton. Dick Reader (RFR) had been scrutinising colour-ringed gulls here over the previous few weeks and it was mainly because of this that I stopped for a look. Good views were possible from the car without disturbing the birds and on this occasion there was a big flock of gulls in the field with others feeding on the nearby tip. Birds were coming and going and I was on my third scan when I noticed a white-headed bird with an apparently long neck and dark eye that immediately rang some bells. It moved closer and then spent most of the next hour or so sat near the front of the flock, walking or making short flights on three occasions. It also eventually did some preening enabling me to see the pattern of the tenth (outermost) primary (p10).

It was a striking cachinnans with a white head and body, small dark beady eye, long washed out slightly droopy looking and with a pointed tip to the bill, longish dull greyish-flesh coloured legs and long wings and with the required pattern on p10. The latter took me some time to see and I was reluctant to let the news out widely until I had done so. I phoned some local birders to say I had a probable cachinnans but wanted to see p10 before letting the news out more widely. Even­tually I saw p10 well and phoned Mashuq Ahmed and the Rare Bird Alert pager service. Dick Reader and Chris Trott arrived at about l2.30hrs and watched it for several minutes. At about l2:40 most of the gulls flew off towards the coast (the tip had stopped working at midday) and we could not find the bird again. I had followed it in flight with the scope but lost it in the melee as it came over the car.

Subsequent searches and regular checking of the site failed to relocate the bird until RFR rang me at lunch time on December 6th informing me he was watching it again in the same field. I was able to watch it for half an hour at closer range than on 16th (only about 70m) enabling extra details to be noted including the patterns of p9 and p5.

Description

Size/structure: It was a little larger than most of the Herring Gulls present but probably on the small side for cachinnans. It had a long parallel-sided perhaps very slightly drooping bill with little hint of a gonydeal angle and a relatively pointed tip, more so than argenteus. The head appeared relatively small and somewhat domed with a sloping forehead and more abrupt nape. The eye was very dark and looked distinctly small and beady. The bird often looked long necked but this varied with posture and it could sometimes look no different from argenteus or michahellis in this respect. It was long legged compared with Herrings with more tibia showing and both tibia and tarsus longer than in adjacent Herring Gulls. It walked with a limp. The bird had quite a long primary projection. The usual stance was distinctly upright with sloping back and the wings held slightly drooped. More often than not though it was lying down. When first found I did notice it looking at its feet, allegedly typical behaviour for this form!

Moult: All the primaries were full grown and fresh.

I concentrated on trying to see the all-important primary pattern. This took some time but I eventually see p10 nicely when it started preening. I had 4 flight views on 16th, which gave a good idea of the general primary pattern, though not good enough to number feathers and say there was definitely a black band on p5 (a feature typical of cachinnans but rarely if ever shown by argentatus Herring Gulls that otherwise can show a surprisingly similar primary pattern to cachinnans). There was much less black in the primaries than in an adult michahellis. P10 had a long white tip with a black band behind this, the black continued basally on the outer web but the inner web was pale behind the black band. The grey (inner webs) between the black outer webs of the others was apparent in flight. The black hooked round along the trailing edge and p5 almost certainly did have some black but I was basing this on how far the black extended - I was not able to count down to p5 on 16th. On 6th better views were obtained as the bird obligingly stretched and partly spread its wing while at rest on several occasions. pg had a small white mirror near the white tip, from which it was separated by a black band. P5 had a complete black band. The precise pattern of pp 8-6 was not noted but there was decreasing black outwards (see sketch).

Bare parts: The eye always looked dark and small, imparting a characteristic appearance to the whole head. The bill was yellow, less bright than most Herrings and much less so than for michahellis, with a small orange spot at the gonys. On 6th, in closer views, a tiny black mark was seen above the gonys spot and a paler whiter tip were noted. The legs were washed out greyish pink. I thought I detected yellow tones at times but RFR and CT did not.

Discussion

The bird was immediately distinctive and I was confident it was cachinnans. It looked nothing like the michahellis present nearby and more like a dark eyed white-headed Herring Gull type. The head and bill shape along with the small dark eye, white head and dull yellow tones to the bill imparted a very characteristic appearance. Structurally it had the long neck, long wings and long legs typical of this form and it might have been a female on size. The mantle and leg colours were typical. Primaries 5, 9 and 10 were all seen well and had the right pattern while the overall primary pattern was also typical. It would have been nice to get some photos but I am confident the identification is 100% safe.

Status and identification in Britain

Cachinnans has been increasingly reported in Britain since Martin Garner and others identified a series of birds at Mucking Tip in Essex from 1995 onwards. Their observations, founded on work in Germany by Gruber (1995), and their papers in British Birds alerted many observers to the possibility of finding and identifying cachinnans in Britain. BOURC has recently accepted some of the Mucking records so this form has finally made it onto category A of the British List. BBRC requested details of all claims up to December 31st 1999 be submitted to them. Subsequently a number of these have been accepted and will be published in this year's rarities report. Only a fairly small proportion of the submitted claims have been accepted as BBRC felt it had to take a hard line with this form. Large white-headed Gulls are notoriously variable and also hybridise much more frequently than smaller gull species. Out of range individuals should be identified with great care using a combination of as many features as possible including moult, size and structure, bare parts and plumage. Primary patterns and mantle tones are important in adults.

There are a number of records (some still unsubmitted) from the very large Hempsted Tip near Gloucester (where I saw my first British cachinnans in August 1999) so further occurrences in our area are to be expected. They are unlikely to be at Harnhill, however, as the tip has now closed! As is the case with a number of 'difficult' large white headed gulls picking birds out is easier than obtaining sufficient detail to prove the identification!

Taxonomy and nomenclature

References:

John Martin - November 2002.