I visited Broome in the west Kimberley of Western Australia for a week in late January / early February 2002 with Robbie Brown from Phillip Island in Victoria. We left Broome on Monday 4th February, but we had the last morning free for a final look around. Cyclone Chris was starting to affect the weather and rain had set in and the wind was increasing to strong but not gale force. We went to the Broome port to check for any seabirds or swifts.
A Kelp Gull that was first reported by George Swann on 28th December 2001 was still at the port and Entrance Point during our visit. We went to Entrance Point and drove down on to the boat ramp to scan. The Kelp Gull was standing at the water line, but about twenty metres to our right was what appeared to be a Silver Gull pecking at a small fish on the sand, but as soon as we looked at it we both immediately commented on the long bill. So we took some notes. Our notes were hampered a little because it was raining quite steadily and we were looking through the sloped windscreen with the wipers working.
The bird superficially looked like a Silver Gull and it was a similar size. It had a bright white head, nape, mantle, throat, breast and belly. The wings were silver like a Silver Gull. The primaries extended just past the tail and were clearly tipped black but there were no windows visible at rest which you normally see in a Silver Gull. The bill and legs appeared dark but we couldn't really be certain in the overcast light. The bill was very obviously much longer than a normal Silver Gull and it appeared to be heavier. I had the impression afterwards that the bill was slightly down curved at the end or possibly slightly hooked on the upper mandible but I never got to check this again.
The bird then flew about fifty metres down to some flat rocks close to the tide line and about two metres to the right of the Kelp Gull. The view in flight was brief but the bright white rump and tail were obvious, as well as the black tips to the primaries. There was not enough time to take in all the details but I had the impression of some white somewhere on the upper wing.
We had limited time before we had to leave for the airport. We quickly skimmed through Robbie's copy of Graham Pizzey & Frank Knight, Field Guide to the Birds of Australia, Angus & Robertson, 1997 and Peter Harrison, Seabirds an identification guide, Croom Helm, 1983 but we didn't match it with anything immediately. Our thoughts were that maybe this was an aberrant Silver Gull. I was about to strip off and run out in the rain to flush the bird to get more details of the upper parts when George Swann turned up. We showed him the bird but we were too far away in the conditions to get a reasonable view. George volunteered and walked down to the shore upwind from the two gulls and walked towards them.
It flew a short distance of three to five metres again giving an impression of some white on the upper wing, but the view was too brief and the wrong angle to get a good look. George returned to his car, and said that the bird had a white outer iris. Later in Perth when I was checking the references, I noted that a Silver Gull has a dark iris in a non breeding adult bird. I asked George if he could flush it again to check the upper wings. He was already soaked in the rain. The bird flew up and away from us and then turned around to the left and flew off in the direction of the wharf. The white on the leading edge of the outer wing (primaries?) was seen with the black tips with no white in the black. The white was wider than just the edge and at the tips it went behind the black. I didn't register any details about the inner half of the wings. The back was silver and the border between the silver back and white rump was level with the back of the wings.
I had the impression of similar features to the Black-headed Gull that I had seen in Broome in October 1991. The bird had a similar wing pattern and the lack of windows in the primaries. We checked Harrison but the bill and head were wrong. We checked Franklin's Gull, Laughing Gull and a few others quickly but they did not match either.
We had to leave for the airport, and we asked George if he could get some more details and possibly photos if the gull stayed around. I was thinking that the bird was an aberrant Silver Gull because I couldn't think of anything else it could be, but I kept thinking that something wasn't right to have such a long bill, no windows in the primaries and the white leading edge.
We returned to Perth. I was busy on the Tuesday but on Wednesday morning we visited Bibra Lake in Perth where there are several hundred Silver Gulls. None of them had bills that looked different. Some had no visible windows in the wings at rest, but these were generally younger birds with some brown still on the wing, and the windows were visible when the bird was flushed. None had the obvious white leading edge of the outer wing. None had a white iris in non breeding adult plumage. This made me look further and talk to a few people.
A friend Rolf Jensen happened to call me on the Thursday and I mentioned the details to him. When I mentioned the long bill he immediately suggested a Slender-billed Gull (Larus genei). I checked Harrison and nearly everything looked right. The main discrepancy was the colour of the bill and legs which should be orange, dark red or dark scarlet. Harrison mentions that the upper wing pattern resembles a Black-headed Gull (Larus ridibundus) which had been my impression of this bird when I saw it fly. The Slender-billed Gull is mostly found in the Black Sea, Caspian Sea, Mediterranean and North Africa but vagrants have been found as far away as Thailand. It is migratory.
I visited Ron Johnstone and John Darnell at the WA Museum on the following Thursday to show them my photographs of the Kelp Gull. Ron showed me museum specimens of Silver Gulls with long bills and only a couple of small white windows in the primaries. He also gave me a copy of his paper R.E.Johnstone (1982), Distribution, Status and Variation of the Silver Gull Larus novaehollandiae Stephens, with Notes on the Larus cirrocephalus species-group, Records of the Western Australian Museum 1982 10 (2): 133-165. I also copied some references about the Slender-billed Gull.
I was still leaning towards the possibility of the gull being a Slender-billed Gull based mostly on the wing pattern. The next week I was putting my photographs away in albums when I noticed the following photographs of Silver Gulls that I had taken for comparison with the Kelp Gull.
The Silver Gull at rest on the right has almost no white window visible in the primaries. The outer iris also looks white. The wing of the Silver Gull in flight is almost identical to what I saw on the long billed gull except there were no white windows. The black is the same, and the white leading outer edge is the same.
These photographs along with the inconsistencies with the Slender-billed Gull led to finally conclude that we had seen an aberrant Silver Gull with an abnormally long bill. The paper by Johnstone suggests that the lack of white primaries could be a feature of Silver Gulls possibly from New Caledonia or maybe just the far north Kimberley.
|© Copyright Frank O'Connor 1997-2002||Visits||Last Modified 23rd March 2002|