Pulau Mantanani: 8 – 12 Oct 2012: Starlings

If there was one mantra I learned from Chris Kehoe’s article on vagrants in East Malaysia, it was “Check the Asian Glossy Starling flocks”!

Occasionally, I could watch them like this.

More often, views were like this! Nevertheless, Chris’s advice was sound, and there were quite often some goodies to be picked out from the flock. You might notice a couple of very white looking birds at the top of the tree – false alarm I’m afraid – just a pair of resident White-breasted Woodswallows. But on further scrutiny, you might pick out another pale bird in the top right of the topmost clump of pine needles…

Nice one – a male Chestnut-cheeked Starling! These aren’t as rare in East Malaysia as they are in the peninsula, but not to be sneezed at nonetheless.

Two of a party of four Chestnut-cheeked Starlings, which were almost the first birds I put my bins on after arrival on the island. This turned out to be my only multiple observation of the species.

Routine checking of starling flocks finally paid off one evening as I was counting frigatebirds flying to roost. The light was practically gone, but I noticed a pale bird (bottom left) and went for a closer look.

Sandy plumage and a banana bill.

Even in semi-darkness and at a ridiculously high ISO, the unmistakable features of a juv Rosy Starling can be seen. There’ve been less than half a dozen records in Borneo, making this the rarest bird of my trip. The last one I saw was on the Isles of Scilly in the UK when I was probably only just out of my teens, so it was good to renew the acquaintance!

Pulau Mantanani: 8 – 12 Oct 2012: Arctic Warblers

With 13 sightings in 4+ days, Arctic Warblers were a frequently encountered migrant on the island. However, what used to be one species has now been split into three: Arctic Warbler Phylloscopus borealis, Kamchatka Leaf Warbler P. examinandus and Japanese Leaf Warbler P. xanthodryas.

The breeding range of borealis stretches from northern Eurasia to Alaska, examinandus breeds on Sakhalin, Hokkaido and the Kurile Islands and possibly on the Pacific Russian mainland, while xanthodryas breeds in the rest of Japan (south of Hokkaido). The wintering range of the three taxa is incompletely known, but borealis is the commonest identified taxon in Peninsular Malaysia, with there being at least one acceptable record of xanthodryas from Penang island (Wells 2007). Mann (2008) records both borealis and xanthodryas as non-breeding visitors to Borneo, with the former being the commoner.

Elsewhere, Paul Leader summarized the status of the various forms in Hong Kong here, with borealis being the only taxon proven to occur there in autumn, but xanthodryas predominating in spring. Clement (2006) suggests that xanthodryas/ examinandus winter in Taiwan, the Philippines and the Sundas.

The full paper documenting the split is here, and, if you just want the main points, useful summaries are here and here. Since the major field differences are in vocalizations, this link is essential listening. It’s worth paying particular attention to the calls, since ‘Arctic type’ warblers are usually pretty vocal in Malaysia. This is what most birds I saw looked like. In both appearance and call, they matched borealis. One bird encountered on 11th Oct looked and behaved quite differently, staying in the top of a mid-sized tree at all times, rather than in the mid to lower storey. The first impression was of  lemony-yellow underparts, rather bright olive-green upperparts and an almost entirely yellow lower mandible.

Unfortunately, the bird was completely silent, but from the plumage, I identified it as either a Japanese Leaf Warbler P. xanthodryas or Kamchatka Leaf Warbler P.examinandus.

According to several sources, xanthodryas has a longer 2nd primary (i.e. the outermost visible primary)  than the other taxa, but I haven’t been able to track down the precise differences in wing formulae, other than the overall wing length (up to 73mm in xanthodryas, rarely over 68mm in borealis (Wells 2007)). Not sure whether anything can be discerned from the two photos below.Xanthodryas has a slightly broader-based bill than borealis. Not sure much can be said from the photos below. If anything, the bill looked more ‘bulbous’ or swollen on borealis and slightly narrower on this bird (which would fit examinandus better than xanthodryas)..

borealis (left); xanthodryas/examinandus (right)

The brighter, greener upperparts of xanthodryas/examinandus are apparent on this comparison.

The head pattern of these two individuals was striking different. The rear of the supercilium of the xanthodryas/examinandus was discontinuous and the lower crescent of the eye-ring stood out in more marked contrast against the darker ear coverts (the eye-ring itself seemed markedly thicker). The supercilium of the xanthodryas/examinandus was creamy yellow throughout, whereas on the borealis, it was whiter toward the rear. Finally, the lower ear coverts of the xanthodryas/examinandus were noticeably washed yellow.

This photo shows the yellowish lower ear coverts well.

Some more shots of this bird, none with a clear side on view of the head!

Overall circumstance make it more likely that this was xanthodryas rather than examinandus, but without the call, I can’t say for sure for now. Photographs of an undoubted examinandus are here, a spring bird. It shows a very extensive dark tip to the lower mandible – more so than is typical for borealis, and much more so than on the bird I saw. It also seems to have a slightly darker moustachial area near the bill, making the bird look as if it has a pale centre to the ear coverts.These may be variable features – but they’re something to look out for at least!

I’ll certainly be taking a much closer look at (and listen to) ‘Arctic Warblers’ in future.

Pulau Mantanani: 8 – 12 Oct 2012: Muscicapa Flycatchers

Asian Brown Flycatchers were among the commonest migrant passerines on Mantanani when I was there, with 19 sightings over the 4+ days.A selection of shots in various lighting conditions. Distinctive features of Asian Brown Flycatcher include the fairly chunky, broad-based bill which is basally yellow. The amount of brown wash across the breast is variable.I saw a couple of Brown-streaked Flycatchers, and managed to photograph one of them. These are described as an uncommon migrant to Borneo. Apart from the subtle diffuse brown streaks on the breast, another distinctive feature is the almost completely yellow lower mandible. On classic birds, only the tip is dark, though there is apparently some variability in this feature.

I saw three Dark-sided Flycatchers – all of them spotty juveniles.

Dark-sided can be rather easily confused with the rarer Grey-streaked Flycatcher, especially the juveniles, which can look long-winged, have rather obvious breast streaking, and can behave differently from adults, foraging close to the ground rather than in the mid or upper storey.However, Dark-sided can be identified in all plumages by the tiny bill and dark centres to some vent feathers. This latter feature is tricky to see in the field – being easier to judge on photos. Occasionally, even on photos, the vent can appear all white, so absence of this feature does not rule out Dark-sided.

Dark-sided typically has a rather domed head and looks small and ‘cute’. Juveniles have a ‘chess-board pattern’ of streaking on the breast, best seen when head-on.This is a Grey-streaked Flycatcher, taken in Miri, Sarawak, on 18 October by Anthony Wong. The different structure of this bird is apparent – it’s a larger, bigger-billed bird with a different head shape. There’s a great comparison of the structure of both species here. The bill of Grey-streaked is mostly dark (often looking all black). The breast streaks are distinct, long, pencil-like marks against a whitish background, quite different from either Dark-sided or Brown-streaked.

I don’t know, but suspect there may be a difference in moult timing between Grey-streaked and Dark-sided. There are photos of 1st winter Grey-streaked here on 29 Sep, and here on 1st Oct in Hong Kong where the moult into 1st non-breeding plumage is almost complete. Another first year bird photographed on 10th Oct in Taiwan here only has a few uppertail coverts still unmoulted. This suggests that Grey-streaked juveniles largely complete their post-juvenile moult before arriving in the wintering area. If so, a spotty Muscicapa in Borneo is likely to be a Dark-sided.

Pulau Mantanani: 8 – 12 Oct 2012: Pipits and Wagtails

Shortly after arrival on 8th Oct, I took my first walk along the coastal path from the resort to see what I could find. Within a few hundred metres, I flushed a passerine off the path, and it landed just a foot or so off the ground on a dead branch, enabling me to get the bins then camera on to it as it watched me nervously.

Not the best pic, but a record shot of a species I last saw in 1986 at Beidaihe, China – a Pechora Pipit. After a pause, the bird hopped back to the ground and scurried off into the undergrowth. Despite waiting there for over an hour, it never showed itself openly again, though I did see it creeping along with its eye on me a couple of times – a very skulking bird!

Pechoras are distinctive pipits – very boldy marked, and most similar to Red-throated (see here). The easiest way to identify them is by the fact that, uniquely among pipits, Pechora’s primaries are visible beyond the rather short tertials. You can see this, even on this poor photo.

Other than that, they have very bold white wingbars and pale mantle braces, are heavily streaked, and the malar stripe doesn’t reach the bill.

Perhaps the biggest giveaway though, is the habitat and behaviour – sneaking around on the ground in thick cover right next to the beach.

On 10th Oct I flushed another in similar habitat at the other end of the island, just inland of the north beach. This one didn’t reappear at all despite a lengthy wait.

The same afternoon, in yet another area, and in the midst of prolonged rain, as I was walking along a coastal path, I flushed another. This time the bird walked out onto the path and remained motionless for a good five minutes, looking wet and miserable. I had put the camera away because of the rain, but I was able to slowly get it out and fire off a series of shots in very poor light.

I was dearly hoping to find a Richard’s Pipit on the island, but I was probably too early. The only other pipits I saw were a pair of familiar Paddyfield Pipits on the football field.Eastern Yellow Wagtails were an abundant migrant, with at least 40 birds on 9th Oct. They favoured the beach and sandy grass in Kg Siring Bukit. How many can you see here?You should have found four. But there were inevitably more than I could see when the birds took flight.

Watching these birds, I realized that it is possible to identify juveniles to race rather easily, or at least, that’s how it seemed to me.This is a juvenile macronyx, with almost no supercilium and a rather dark grey crown and ear coverts.

I took these birds, with a broad, long supercilium, to be juvenile taivana.The commonest variant was this one, with a thin supercilium, sometimes broken in front of the eye, which I took be to be tschutschensis. The extent of marking on the breast was very variable, from virtually none to quite heavy and distinct.

These juv Eastern Yellow Wagtails exhibit several supposedly strong features of Citrine Wagtail – white vent, dusky rear flanks, lack of olive tones, even a dark lateral crown stripe on some. None, however, showed the broad white wingbars and pale ear covert surrounds of Citrine.There was quite an influx of Grey Wagtails in my few days. I recorded none on my first day but at least 8 birds on the 10th, with another 6 on the morning of 12th Oct.

Pulau Mantanani: 8 – 12 Oct 2012: Waders

Offshore islands aren’t known as hotspots for waders, and Mantanani didn’t prove to be one. But it was very cool to hear Wood Sandpipers passing over calling – usually invisible in the vast blue sky – regularly. Once I did manage to spot a calling wader overhead – just a Pacific Golden Plover – but visible migration is always special!The Point had two long-stayers, let me introduce them:

An adult Red-necked Stint and a juv Ruddy Turnstone.

They just bummed about on the beach all day and supped from fresh coconuts – reckon they’ve got this migration thing sussed!Crowds – what crowds?

This is how I knew it wasn’t a Semi-palmated Sandpiper!A bit of surfing!The only problem with a beach like this – it’s HOT – so keep your feet off it as much as possible!

And a bit of exercise when I ventured too close!

Pulau Mantanani: 8 – 12 Oct 2012: Raptors

The first raptors I saw were also probably the rarest – a couple of juvenile Chinese Goshawks arriving high off the sea from the north on 8th Oct.

These are described as ‘scarce’ (Mann) or ‘very uncommon’ (Myers) in Borneo. I saw another one the next day!

The most evident raptor was Japanese Sparrowhawk. I saw these zipping about various parts of the island almost daily, but it was hard to estimate numbers – whether just one or two lingering to catch migrants, or more passing through. There was one bird that regularly hung around The Point, shown here having a go at a Collared Kingfisher!

Most views were like this – a dash-past! Once I was watching an Asian Brown Flycatcher when a ‘Jap Sprawk’ smashed into the bush where the flycatcher was. It all happened so fast I really couldn’t say whether the flycatcher escaped or was caught, but either way, I didn’t see it after that!

This is the bird that hung around The Point. Imagine being a small passerine and arriving on the island exhausted after a substantial sea-crossing, only to find these lethal things waiting to pick off anything that’s not at the very top of its game! Migration is just amazing!My notebook  records that this Osprey flew over the beach at 6.17am, just after a White-throated Needletail went through, showing that it pays to be out at first light! It was my only sighting.

This adult calidus/japonensis Peregrine was sitting looking utterly miserable in a storm (I wasn’t feeling at my best myself, being soaked to the skin!). I had had a brief view of an unidentified falcon soaring with the frigatebirds the previous day, so I was glad to clear that little mystery up – well, probably…!

The locals! I believe the pair of White-bellied Sea-eagles at the north-western end of the island had three youngsters – though perhaps not all from the same clutch.

Pulau Mantanani: 8 – 12 Oct 2012: Frigatebirds (3) – juvs and subadults

Let’s start with an easy one!

With the obvious bulk and long bill this is clearly a Christmas Island Frigatebird (CIF). Juveniles are not known to be sexable on plumage, but since females of all frigatebirds are larger and longer-billed than males, I would hazard a guess that this is a female. Full juvenile plumage would have a solid breast band (two ‘lobe shapes’ either side of the breast meeting in the centre). Moult into 2nd year plumage begins to replace the black breast band feathering with white, from the centre outwards, and this has begun on this bird. The belly patch on juv CIFs is hexagonal (triangular on LFs) and axillary spurs originate behind the line of the breast band, as here.

The angle of the photo makes id. trickier , as the bill proportions and belly patch shape are disguised by the slightly head-on perspective. Nevertheless, the belly patch is roughly hexagonal, the axillary spurs originate behind the breast band, and the ‘double-lobe’ shape of the breast band can all be seen, so I make this a juv CIF too.

This juvenile Lesser Frigatebird (LF) has a distinctly triangular white belly patch, the ‘base of the triangle is formed by the rear border of the breastband, which is more or less straight rather than formed by two obvious lobes. The axillary spurs originate from the front of the belly patch (extending outwards from the basal corners of the triangle), and are triangular rather than parallel-sided.

A slightly older juvenile LF. The tawny head feathers have become white as a result of abrasion, and the breast band has begun to whiten from the centre.

Apparently the same individual, but the axillary spur on its left wing is almost completely obscured.

A couple of second year LFs. This is in some ways the most confusing plumage, as at this stage, LFs share the white belly of adult female CIFs. In the 2nd year, the breast band disappears and the white belly (from juvenile plumage) starts to develop black, adult-like colouration.

The presence and shape of the axillary spurs is of critical importance for identification at this stage. Great Frigatebird (GF) lacks them; CIF has parallel-sided, forward-angled spurs, or lacks them; and LF has triangular, outward-angled spurs. 2nd year CIF has black ‘breast tabs’ which are absent in the other two species.

I think these are both 3rd year LFs. A pale throat and breast on an otherwise dark frigatebird is usually an id. feature of GF. However, both these birds have LF-shaped axillary spurs, and I think the pale throat can be explained by the fact that the birds are moulting from 2nd year (white head) to 3rd year (dark head) plumage. I think the upper bird is a female (with an adult female-like breast saddle), and a lower one a male (as the black on the belly comes too far up toward the breast for a female, starting to isolate the white axillary spurs).

Frigatebirds all sorted now? Try identifying, aging and sexing the birds in these four pics and see how you get on!

Species, age, sex (where possible)?

Left to right:

Bird 1

Bird 2

Bird 3

Left to right:

Bird 4

Bird 5

Bird 6

Left to right:

Bird 7

Bird 8

Pulau Mantanani: 8 – 12 Oct 2012: Frigatebirds (2) – Adults

Now down to the nitty-gritty of frigatebird identification! For this I relied pretty much exclusively on the seminal identification paper by David James, Identification of Christmas Island, Great and Lesser Frigatebirds, which came out in the very first BirdingASIA back in 2004.

The first thing which surprised me was how different Christmas Island Frigatebirds (CIFs) and Lesser Frigatebirds (LFs) were structurally. CIFs (left two birds) were visibly bigger, stockier and broader-winged even with the naked eye, and the bill was markedly longer.

Somehow, this made CIFs stand out even when birds were differing distances away, but it became even more obvious when they were directly alongside each other, as here (two LFs flanking a CIF).

Here, the LF (left) is actually closer than the CIF, which gives you a good idea of the size difference!

Now to plumages. The above image shows two adult males. Male CIFs have a distinctive squarish white lower belly and male LFs just have thin ‘spurs’ that angle back from the axillaries to the body. Adult male Great Frigatebirds (GF) are all black, but I didn’t see any of those! This looks like one, from Jason’s blog.

An adult male CIF (top 2 pics). I think the lower image may show a 4th year bird, as the lower edge of the breastband, the belly-patch and axillary spurs all show a shape reminiscent of younger birds, and the gular pouch appears pink rather than red. But it may just be an adult variant.

Adult male LFs. These aren’t so hard!

Adult female CIF (left) and LF (right). This seemed to be the commonest age and sex of both species on Mantanani. Female CIFs, with the white extending right back to the vent, are very distinctive.

Some adult female CIFs.

Adult female LFs have a black hood, white (usually) breast with a concave lower edge, black belly and white triangular spurs. The tawny wash on the breast is said by James to be present on some birds, but not typical. It seemed a common feature of Mantanani birds however.

Juveniles and subadults get a lot trickier!

Pulau Mantanani: 8 – 12 Oct 2012: Frigatebirds (1) – Flocks

Some shots of the amazing daily spectacle of frigatebirds leaving and gathering to roost. I made a count of 5,000, with an estimate of 10% being Christmas Island Frigatebirds. See how many you can spot in the pics above – I’ll be writing more on frigatebird id in the next post.

Another video is here . One odd thing is that the birds were virtually entirely silent (and least when overhead).

I decided that no species of frigatebird should be called “Magnificent Frigatebird” – they’re all magnificent! In fact, a frigatebird in flight is a definition of magnificent!

Pulau Mantanani: 8 – 12 Oct 2012: Herons

Cattle Egrets are ubiquitous on the island, in all habitats, including deep forest! I also saw some birds flying high overhead – and these were probably migrants.

Great Egret – I watched one flying past at sea on 9 Oct being mobbed by Lesser Frigatebirds! On 10 Oct there were 6 birds, including 3 at the abandoned resort.

Intermediate Egret – Three were at the abandoned resort on the 10th and 2 on the 9th. Rather incongruously, one was foraging in the forest!

Little Egret – 6 on the 8th, and 1 on 9th and 10th. One of the more extraordinary birding experiences of my life was watching the flock of 6, with 1 Cattle Egret, fly in and land in a sheltered bay. One bird crouched down in the water, as if to cool off. A few moments later, it was dead! The others, somewhat startled, flew off and landed a short distance away, leaving the corpse to float off with the tide! A case of death by natural causes I suppose.

Black-crowned Night-heron – At least 5 loudly calling birds were spotlighted flying over at night, while I was owling!

Little Heron – Two birds heard at night on the 10th and 12th, with a juvenile seen at the abandoned resort on the 11th.

pond-heron sp. – One bird sat just inland of the beach on the 8th, looking a little the worse for wear! If it was a migrant from points north, I suppose the probability was that it was a Chinese. Either way, pond-herons are scarce in Sabah.

Grey Heron – 1 bird flew over on the morning of the 12th.