Living and birding in England for many years until 2005, I saw most of the gulls on the British list at one point or another. I used to enjoy scanning the vast gull flocks at Dungeness looking for a stray Caspian Gull, Yellow-legged Gull, or a winter Glaucous Gull. However, the identification and taxonomy of large gulls is not a subject that one has a lot of opportunity to get involved with in southern Taiwan, where they are generally very scarce winter visitors.
Driving south on Highway 17 on Tuesday afternoon, I was crossing a big river bridge at about Km 121 when my eye was caught by an adult gull on the estuary below. Even before I even stopped the scooter, my immediate reaction was that it was very dark on the mantle. The bird was wary, and I wasn’t too far away from it, but it was reluctant to leave the dead fish it had found. The mantle was a slaty-grey in color, several shades darker than on the Mongolian Gulls I had seen earlier in the day. Its legs were very bright yellow-orange, again quite unlike the dull pinkish legs of Mongolian Gull. The wings appeared especially long, another feature good for Heuglin’s Gull. Scanning identification papers and photos on the internet when I got home, the only feature that was perhaps abnormal for taimyrensis Heuglin’s Gull was the very white head (Heuglin’s Gull typically shows a lot of head flecking in winter), but there is much variation between individuals; this bird could have just been very late moulting out of breeding plumage.
According to the literature, the taimyrensis form of Heuglin’s Gull is a regular but uncommon winter visitor to Taiwan. The science of large gulls is very much a work in progress, but I am happy for now to be able to add it to my life list. It’s my first lifer since Slaty-legged Crake back in August.
In other news, visits to Cheting, Qigu, Budai and Aogu today produced a respectable total of 70 bird species. Perhaps noteworthy were a Black-faced Bunting and two Daurian Redstarts in the coastal forest at Qigu, two Ospreys on the estuary there, and a couple of Greater Painted-Snipes flushed from marshes along the Qigu embankment. At Budai, two adult Mongolian Gulls, 12 Common Pochard, a Garganey and a Richard’s Pipit, plus a huge flock of at least 800 Whiskered Terns resting on the marshes near Highway 17 at Km 134.5. At Aogu, no sign of the reported Hooded Crane, but plenty of wintering birds including Avocet and Black-headed Gull.
Of interest to birders visiting from overseas, Black-faced Spoonbills are currently common and easily found at all the sites mentioned.
Lifer: Heuglin’s Gull (total 1,790).