Terns Terns Terns...Sooty Tern!

Terns at Kung Chau - four species here

News of a Sooty Tern spotted at Kung Chau off Tap Mun came the day before, it is a rare tern that only occasionally come through Hong Kong. A boat was organised to pick us up at Tap Mun (also known as Grass Island) and we headed out to look for it at the tern colony on Monday. Weather did not look good as I set off from Ma Liu Shui pier, but luckily the rain eased off slightly, by the time we got to Tap Mun it was only drizzling.

The boat arrived at Kung Chau, a small rocky island on the east side of Tap Mun, this had traditionally been one of the tern colonies around Hong Kong north eastern waters. As we arrived we saw many terns resting on the rocks, I scanned the terns and found our target sitting right in front of us. Juvenile Sooty Terns differs from all the other terns by being dark brown overall, they blend in extremely well along the rocks. They in fact look a little bit like a Noddy.

Kung Chau from the boat

Terns at roost

Sooty Terns standing amongst Common and Roseate Terns

We enjoyed brilliant views of the bird at fairly close range. AFCD had set some guidelines in viewing breeding terns in Hong Kong, for example not landing on the island or disturb nesting terns. There had been previous incidents where adventurous locals landed on the island and potentially damaging the eggs at the nests, these activities could potentially put the colony at risk, reducing the breeding success rate. With modern cameras, taking photographs on a rocking boat is not a problem, image stabiliser and higher ISO is able to get me sharp images, so there really is no actual need to land on the island if your objective is just to get good photos. The Sooty Tern remained fairly stable and returned to almost the same spot every time.

Sooty Tern - juvenile

Overall the bird looked pretty healthy, flying around gracefully. It was easy to pick out from the rest of the flying terns by it's larger size and much darker body. It was also quite inquisitive, occasionally flying towards our boat to see what we were up to.

Sooty Tern - inflight

Being larger than other terns, it did not seemed bothered by other species, although on one occasion we saw an adult Bridled Tern chasing after the Sooty, but otherwise it seemed to fit right in. Traditionally Sooty Terns breeds much further out in South China Sea and rarely venture this close to Guangdong coast, I suspect this young bird must have followed the wrong flock into Hong Kong waters.

Sooty Tern harassed by Bridled Tern

There are three tern species that breeds in Hong Kong annually, the only one that can be confused with the Sooty are Bridled Terns. They are dark brown above and pale greyish below, with a very smart looking eye mask and a white 'unibrow'.

Bridled Tern

There were a few young Bridled Terns present, I presume they were 2nd or 3rd year birds with much paler head patterns. Breeding terns in Hong Kong usually return from May onwards, so I don't expect to see any chicks this early on in the breeding season.

Bridled Tern - 2nd / 3rd year birds perhaps?

We saw surprisingly few Black-naped Terns at the roost, either most have not returned yet or numbers are higher on other islands? They are absolutely stunning birds that look all white inflight, breeding birds show pinkish breast.

Black-naped Tern

The final local breeder is the Roseate Tern, they are my personal favourite with the beautiful pinkish wash on their belly and red bills and legs during breeding season. I counted no more than five of these at Kung Chau. This species's numbers had decreased in recent years, I sure hope their numbers will climb back up again.

Roseate Tern

To my surprise there were plenty of Common Terns present at the roost. Common Terns are migrants in Hong Kong, there are two subspecies that can be found in Hong Kong, one with dark bill and the other with red bill. The dark billed birds are of subspecies longipennis, they breed in central Siberia to Alaska. The red billed birds are either tibetana / minussensis.

Common Tern - race tibetana / minussensis on left, race longipennis on right

Common Tern - race tibetana / minussensis

longipennis are usually less common in Hong Kong, this was the case here as I only saw two dark-billed birds. A non-breeding Common Tern was also present, with it's reddish bill base and brighter legs I would put it as tibetana / minussensis.

Common Tern - race longipennis

Common Tern - non-breeding

A single non-breeding White-winged Black Tern stuck out like a sore thumb. While Whiskered Terns of various plumage stage were also present, although I have seen them at sea, this is the first time I've seen marsh terns roosting on a rocky tern colony.

White-winged Black Tern - non-breeding

Whiskered Tern

It was a very enjoyable morning to catch up with the Sooty Tern as well as six other species of terns at the same location! It certainly will be bird of the month for June if nothing new comes our way...Meanwhile, here are some interesting action shots at the colony from the other day.

Splash zone?

Terns are not just found at the breeding colony, I saw up to 25 Whiskered Terns at Tai Sang Wai late last week, a pretty high count for this species at this time of the year, fish ponds are certainly a more classic habitat to find these terns.

Whiskered Terns