Thursday, April 28, 2011

19th April 2011: At sea off Tanjung Dawai, Kedah

My first trip on the boat since 3rd Jan, but we're now entering the time of year when things get interesting, so I should be a more frequent passenger in the next couple of months!

There was a bit of "vis mig" (visible migration) going on - a few Barn Swallows and one group of five Blue-tailed Bee-eaters travelling north over the sea. It may surprise you that butterflies and dragonflies are quite frequently seen migrating over the sea! I managed to snap this butterfly heading north, well out to sea!

Seabirds, though, were in surprisingly short supply, as were fish! We went several hours without seeing a single tern, unheard of at this time of year. Eventually, however, we connected with a few birds.

Two Common and two Bridled Terns shared a plank!

The last to fly!

Part of a roosting flock of Common Terns.

We estimated not more than 300 Common Terns present today - far fewer than usual.

Yet another Common Tern with a deformed bill!

A lone fly-by Greater Crested Tern was a typical record.

As was this brief sighting of a solitary Aleutian Tern.

There was just one Pomarine Jaeger today, but a very fine one it was - an adult dark morph bird.

Not very close unfortunately.

We saw at least six Long-tailed Jaegers.

These are challenging to photograph in the harsh midday light. They never hang around, so we have to make the most of the brief opportunities that come our way.

This subadult is in wing moult.

I was interested to see that this bird had a double layer of inner secondaries! The new still-growing feathers are visible beneath the paler old ones, which project beyond the line of the trailing edge of the wing.

A Long-tailed Jaeger catching a meal. It zooms in on a Common Tern which has recently fed; harassing it until the fish is disgorged (2nd pic), whereupon the tern is left alone and the jaeger picks up and eats the fish in mid-air (pic 3). Seeing this performance repeated often, I wonder how this behaviour benefits the jaeger. It must surely take more energy to obtain a meal in this way than by simply catching a fish from the sea. Can anyone enlighten me why jaegers/skuas use this apparently uneconomical and energy-inefficient hunting strategy?

A first year bird I think.

An adult. Relatively few have full-length central tail feathers like this bird.

Three adults together.


he dark underwing and dusky rear half of the body are good field marks of adult Long-tailed.

A pale morph 'Pom' (left) and a Long-tailed for comparison. Note the difference in the pattern of pale areas on the body, and the dark secondaries contrasting strongly with the pale coverts on the Long-tailed. There's also a difference in size and structure which is more obvious in the field than on still photos; Pomarine being a much bigger, more heavyset species.

When it became obvious that fish were few and far between, our boat headed back to port early, which gave us a chance to look around the nearby flooded paddyfields and coastal scrub before dusk.

There were small numbers of Pacific Golden Plovers and Oriental Pratincoles in the paddyfields. The latter were loafing around, but there were no signs of breeding in progress. All appeared to be in wing and tail moult.

Quite a range of underwing colour, and also in extent of peach wash on the lower breast.

I was never conscious of being mobbed, but these birds did seem to want to 'check me out', so perhaps they are thinking of breeding.

The secondaries show thin buff tips.

In the coastal scrub we found an active and obliging male paradise-flycatcher - but which one? The upperparts at times looked dark enough for Japanese, but the underparts were surely too pale!

 Eventually, with a bit of reading, we realized that this must be an 'incei' Asian Paradise-flycatcher, one of the northern-breeding migratory races. According to Wells, there are two races which could occur as migrants - incei and saturatior, and two resident subspecies, indochinensis and affinis. Incei (the brown form) differs from the others in having maroon chestnut upperparts rather than rufous chestnut, and a glossy black head and throat which is sharply delineated from the paler underparts. It lacks a grey hind collar, which is more prominent in the resident races.

This bird had a vestigial grey collar, only noticeable at certain angles.

The Sinoi-Himalayan 'saturatior' race has a more prominent crest and is even whiter below (see this image). There are two confirmed records from southern Thailand but none yet from Peninsular Malaysia.

The black head was sharply demarcated from the breast. The smoky grey breast and small crest rule out saturatior.

An educational bird to finish the day!

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