Friday, January 28, 2011

25 January 2011: Sarawak Waterbird Survey - Kampung Luba

On my last morning we went west of Kuching to a small beach roost.

Dawn looking toward Mount Santubong.

As we drove I was asking Daniel about Cinnamon-headed Green Pigeons when he pointed up at the top of a roadside tree, stopped the car and said - "There - is that one?" Indeed it was - a pair in fact , and a lifer for me!

This is the female, with her distinctive narrow, red-based bill.

The only access to the beach with the roost was via a padlocked barrier across a track. A notice next to the barrier gave a phone number and said that an entrance fee of RM5 would be charged. I thoroughly approved of this piece of initiative! I'm all for local communities looking after their wild spaces, and profiting from them.

The roost itself was quite small - about 115 birds of just 6 species.

We approached the birds by driving along the beach. I took the 'back seat' - sitting in the open with some camo webbing over me.

The species present were all sandy-substrate preferring species, with Greater Sand Plovers being the commonest. Greaters tend to outnumber Lessers in sandy habitats, since their preferred prey is crabs, whereas Lessers feed on mud-loving marine worms.

There was one male in very fine fresh breeding plumage. Greater Sand Plover moult a month or two earlier than Lessers in spring, perhaps because their breeding grounds are further south and therefore become available earlier in the northern spring.

This bird had undergone a full moult of both body and wing and tail feathers and was in pristine condition.

There'll be many more of these stunning beauties in the next couple of months!

Sanderlings and Kentish Plovers made up the bulk of the rest of the flock. You can see the distinctive feet of the Sanderlings in this picture. Sanderlings are unique among the calidrid sandpipers in lacking a hind toe; a modification which helps them run at great speed.

Sanderlings look superficially like stints.

However, their feeding habits are quite different. They 'chase the waves' in flocks - speeding along the tideline to catch prey left by retreating waves and frequently burying their bills up to the hilt in the waterlogged sand.

Surf's up - gotta catch that wave!

Kentish Plovers in East Malaysia are very interesting! 90% of them have pale flesh-coloured legs. Males are rather dull on the crown and the breast patches are long, sometimes extending right across the breast to form an unbroken band. They look just like birds which occur in Japan (see here and here and not at all like the birds we get in Peninsular Malaysia. These are mostly dark-legged, have shorter breast patches and the males are much brighter-crowned (see this bird, photographed in Penang on 21 January 2007, for example). In my view, these East Malaysian birds correspond to what Deignan identified as the 'nihonensis' race, whereas the West Malaysian birds appear to be predominantly the nominate 'alexandrinus' race.

Another pink-legged male.

A male and female.

A female.

This bird had pale grey legs.

Note the complete breastband (and pink legs) of this bird.

One could be forgiven for confusing these pale-legged, breastbanded Kentish (left) with Malaysian Plover (right).

A male Malaysian Plover, with the typically stubby-billed, long-legged structure of the species.

The second bird had some male plumage characteristics (black breastband and frontal bar) but was behaving in a way that indicated it must be the female of the pair.

A few Terek Sandpipers made up the party.

I'm very happy to pay RM5 if it keeps the beach free of disturbance and litter!

24 January 2011: Sarawak Waterbird Survey - Jemukan fishponds

Today we went to check out a couple of roosts we'd found on the first day of heli surveys. The was this one on the bund of a fish-pond near Jemukan. This site is remote and not visible from any road, and really demonstrated the value of doing aerial surveys to locate roost sites.

We had just set up our makeshift hide when the birds arrived pretty much en masse.

Lots of birds (1,900) but not many species (just 5)!

Four of the five species can be seen here: Curlew Sandpiper, Lesser Sand Plover (both numerous in the picture), Greater Sand Plover (two bird in the centre, one above the other), and Broad-billed Sandpiper (the alert bird on the extreme right, just below centre). The fifth species (missing from this photo) was Pacific Golden Plover.

The birds packed together on top of the bund made counting a challenge!

And I took lots of flight pictures in case we had missed anything unusual in the packed roost.

Which indeed we had! Minute scrutiny of photos of the flying birds after we got home revealed this...

A leg-flagged Curlew Sandpiper. All along the East Asian-Australasian Flyway, shorebird researchers from different countries attach uniquely coded plastic bands to the legs of birds they catch. As these birds are sighted by other researchers up and down the Flyway, gradually our understanding of different populations, routes and important sites builds up.

This bird had a pale blue flag above an orange flag on its right tibia. By checking the EAAF leg-flagging protocol, available here, we discovered that the bird had been flagged on Kyushu, the southernmost major island in Japan [Edit: Sharper eyes than mine have determined that the colour of the lower flag is yellow, not orange, which means that the bird was flagged in the Bay of Bohai, China. Good job we got photos!] All sightings of leg-flagged birds can (and should!) be reported to the Australasian Wader Studies Group using a simple online report form.

Another piece of the puzzle!

Another check of my photos revealed that it was there in right front of us! A case of not seeing the wood for the trees!

Just before dusk we went to check out the second roost, some fishponds in mangroves. No photos - the light beat me, but a notable roost of 150 Chinese Egrets, and a calling Nordmann's Greenshank among the 100 Common Greenshanks rossting at the ponds.

For details of how you can volunteer to take part in the Sarawak Waterbird Survey, see here.

Thursday, January 27, 2011

23 January 2011: Sarawak Waterbird Survey - Sejingkat ashponds

Today we went to count the ashponds photographed here. The main roost is in the large, half-filled pond this side of the road (looking from the helicopter).

It's a major roost for curlews and greenshanks, and, as curlews are among the shiest of waders, we went early and set up a hide for the three of us. The weather was decidedly better today, and we had the sun behind us.

The birds accepted the hide as part of the scenery and came in pretty close.

Before the roosting waders arrived however, we had some time to observe the species which habitually feed at the ponds.

The Black-winged Stilts were distinctly different in both plumage and vocalizations from birds in the Peninsula. Compare the plumage of these birds with these, photographed in Penang recently. The calls heard were a high-pitched piping, lacking in the nasal, trumpeting quality of West Malaysia birds. This doesn't necessarily mean that these birds are a different subspecies, as the differences could be clinal, but it does at least suggest that these birds are a relatively distinct population from the Peninsula birds.

Marsh Sandpiper (right) and Common Greenshank (left) numbers were greatly augmented by birds coming in to roost, but there were a few which evidently remain at the ponds to feed. The two species are similar, but are readily separable by size, structure, plumage and call.

The Marsh Sandpipers were feeding on dragonfly larvae. Can anyone identify the species?

We counted 337 Common Greenshanks. There were also two Nordmann's Greenshanks, but they kept to the far side of the pond (typical!) with the Grey Plovers.

The only Common Redshank seen (right)!

Curlews were the most numerous group present. In West Malaysia, among a roost of 6,000 at Kapar, you're lucky to see one or two Eastern Curlews. Here, the situation is reversed. We counted 541 Eastern and just 63 Eurasian Curlews.

The two are easy to tell apart in flight, as the rump and back are white in Eurasian and brown in Eastern.

The same colour scheme is reflected from below - Eurasian (left) has glistening white underwing coverts and a white leading edge to the wing; Eastern has a well barred underwing.

So these are all Eastern.

Once they've landed it's a bit more challenging, but the base colour of Eurasian's plumage is distinctly paler than most Easterns, and in particular, the white vent usually stands out. I can see six Eurasians in this lot.

More subtle differences can be made out at close range. The rear flanks have drop-shaped dark shaft streaks on Eurasian, whereas these feathers have quite prominent transverse barring on Eastern. Also, all the upperpart feathers have much more prominent barring on the feather edges on Eastern than on Eurasian, and this is particularly obvious on the tertials. This last feature can be obvious at a surprising distance.

Eurasian Curlews have a whitish base colour to the supercilium, and two 'eyebrow spots' are usually obvious when the bird is sleeping face-on, whereas, on Eastern, the face pattern is relatively unmarked.

It's commonly said that Eastern Curlews have longer bills than Eurasian, and while this may be true on average, there's such variation in bill length that it isn't a good field character.

Check the difference in bill length between these two Eastern Curlews!

The Eurasians stand out obviously in bright sunshine.

Much less so when the sky is overcast. How many can you make out here?

Eastern Curlews are the largest migratory waders in the world. This one dwarfs a Common Greenshank alongside.

Some more Eastern Curlew portraits.

And a summary of the differences between Eastern and Eurasian to conclude.

For details of how you can volunteer to take part in the Sarawak Waterbird Survey, see here.