On Gulls: Black-headed and Brown-Headed

Brown-headed Gull (1w)

Larus brunnicephalus

Don Hoi Lot, Samut Songkhram Province

29.12.11

Brown-headed Gull (1w)

Larus brunnicephalus

Bang Pu, Samut Prakhan Province

07.01.12

Gulls have been the highlight of 2012 so far for me. Quite unexpectedly so. It's also been very educational too. I think my knowledge of these fascinating pelagic birds has increased sevenfold in 2012. The Brown-headed Gull is the most common gull in Thailand followed by the smaller Black-headed. However, they are not that easy to separate and provide a good introduction to the complexities of gull identification.

Less than two weeks ago I posted the top picture of the gull sitting on water on BirdForum for help with identification. I thought I had a shot of a Black-headed Gull: it had the black ear spot and dark iris referred to in most of the field guides as this species' diagnostics. I must own to feeling unconvinced when told it was a Brown-headed "first winter"! I even posted a second picture to show the detail of the eye! My friend Tom Backlund told me there could be no doubt it was a Brown-headed. Crest-fallen, I was! What was I not seeing?!

Learning point ⌗1: get a shot of the bird in flight or with its wings extended. In the second picture the black primaries and secondaries dispel any doubts about this bird's identification: it is a first winter Brown-headed Gull. This is supported by the dull orange bare parts of the gull: the bill and the legs.

Black-headed Gull (2w - adult)

Larus ridibundus
นกนางนวลซอบชาว

Bang Pu, Samut Prakhan Province

07.01.12

Now apparently the Brown-headed Gull's bill is heavier/stouter than that of the Black-headed. I find this a hard distinction to make. Fortunately I managed the above flight shot of an adult Black-headed Gull. Note the blackish tips of the bird's primaries.  That is one of the key diagnostics. From Harrison's Seabirds : "....prominent ....blackish tips to outer 6 or 8 primaries". Please note this shot was taken with the camera hand-held minus the telescope. That is how close it is possible to get to the birds at Bang Pu. But I would find it impossible to separate this bird from the Brown-headed without being able to see the wings. Apparently it is a smaller bird too, but my eye is not yet good enough to discern a significant difference.

The above shots are a tentative comparison of first winter Brown-headed, left, and the adult Brown-head, right. The most obvious difference is the colour of the bare parts, the bill and legs. In the first winter they are dull orange and in the adult they are a bright red.

The above shots highlight the difference in bill colours between Adult, left, and First Winter, right; the difference in the iris tone is also clear with the first winter being darker. I am a little disappointed I didn't manage to get some close-up shots of Black-headed. Something for my next trip to Bang Pu.

Bang Pu is a really excellent place to view and photograph gulls. They come in huge numbers and they really do come in close and perch on bamboo stakes close to the pier. Moreover rarities show up most years: my recent visit was to twitch Mew Gull, a real rarity for Thailand and last year there was a Sooty Gull, a first record of this species for South-east Asia. Slender-billed Gulls are also seen here on a regular basis.

An additional attraction is the facilties: at the pier end there are a number of excellent restaurants famed for their sea-food. Bang Pu can get busy, however, as it is a popular spot and a very convenient distance from Bangkok: a bit like Largs and Glasgow, well, errrrr, not quite!