Sunday, 25 August 2019

Swiftlets and Stints

A weekend rudely interrupted by a tropical storm (which meant a good soaking for me on Sunday). Saturday proved to be the pick of the days, with dry but gloomy conditions for much of the morning, all of which was spent at Tu Cheng. The conditions had pushed a few 'summer swiftlets' in off the coast (at least eight, though likely many more than this). These proved to be quite vocal (I heard my first one before I actually saw it), flying around calling with 'chit chit' and shrill 'zrreeuw' notes (the latter vaguely reminiscent of Broad-billed Sandpiper). Calls were sadly too intermittent to pin down a recording, but a few more grainy images could be added to the album.

There were many hundreds of Red-necked Stints in the area, all adults in various stages of moult. As it was too gloomy and windy to entertain thoughts of looking in woodlots, I thought I may as well document the transition from (worn) summer to (almost) winter plumage in this species. 

Sunday produced a further two 'summer swiftlets' zipping around over my coastal woodlot, but the deluge arrived before I could get anything other than unwanted record shots. If these are Himalayan Swiftlets like most people assume, then they have the most extraordinary migration (an impromptu peregrination around the South China Sea at the height of summer) of any species I have ever encountered! Above photos taken in Tainan City 24/8/19.

Wednesday, 21 August 2019

Gray's Grasshopper Warbler

After what has felt like an eternity, the incessant rain finally stopped today, giving me my first chance of the autumn to inspect my woodlot and see how it looks for the autumn migration. I was greeted on arrival by three 'summer swiftlets' feeding over it: not a bad start (though the skies remained gloomy and the birds were never at the best of angles to do much with them).

It was even gloomier under the canopy, but the woodlot has stood up quite well to the summer and parts of it remain accessible. There were half a dozen Arctic Warblers flitting around in the low trees and up to four Gray's Grasshopper Warblers skulking on the ground. Surprisingly, I managed to see each of these sufficiently well to determine that the P9 was long (close to P8 in length), leaving no need to consider amnicola (a bird I used to think occurred here on passage but now do not).

With the passerine migration up and running, I can finally turn my attention away from waders and relegate them to 'last resort'. After such an awful spring twitching, I'm rather looking forward to an autumn focused solely on my local patch! Above photos taken in Tainan City 21/8/19.

Sunday, 18 August 2019

Grey-throated Sand Martins (3)

I've taken a keener than usual interest in Grey-throated Sand Martins this summer in the hope that a better understanding of these might lead to a better understanding of Riparia martins in general. The large flock that typically frequents the Tseng Wen River has returned (after an inexplicable absence), with several thousand individuals now in the area bordered by Tu Cheng, San Gu, and the coast. A group of several hundred scrutinised at Tu Cheng over the weekend surprisingly contained no other migrant/vagrant Riparia (which are now overdue). It also contained no fresh-looking juveniles (indicating that breeding locally has long since finished). Most adults had either completed their post-breeding moults or were growing P9, suggesting that pretty much all adults in this area will have finished their complete moults by September.

Birds somewhere mid-primaries all appeared to be juvenile. Whilst the outermost primaries typically showed a quite unexpected amount of wear (given that these feathers are not that old) at the tips, they retained the pale fringe to the inner webs of a 'newish' feather. Presumably (as they do not face the rigours of a migration) the flight feathers of juveniles of this species need not be of an especially durable quality. In contrast, the greater coverts of these birds typically showed no traces of wear, appearing fresh (and 'same age') with a narrow white fringe, indicating that they were all grown at the same time relatively recently and are therefore juvenile.

Once both the inner primaries and greater coverts of juvenile Grey-throated Sand Martin have been replaced, there seems to be no way of separating a hatch-year bird from an adult. The individual below could therefore be a retarded adult or an advanced juvenile (perhaps the latter from the subtle yellowish tones to the throat). Whilst the post-juvenile moult of Grey-throated Sand Martin lags the post-breeding moult of adult (by just a few weeks), I assume that in the second calendar year the complete moult becomes synchronous with that of adult.

Striated Swallows nest a bit later than Grey-throated Sand Martins and, as they are also larger birds, the complete moults are started that bit later and progress more slowly. Still, I was surprised to find a juvenile Striated Swallow that had not yet started its post-juvenile moult in amongst the Grey-throated Sand Martins on Saturday. A quick detour to look at a few other juveniles revealed most to now be in moult, with the most advanced birds having dropped P4. I had hoped to look at few adults, too, but was beaten back by torrential rain on both Saturday and Sunday.

As a fan of big gulls (in which it is a vital consideration), I've often fancied that timing of moult might be of use in assigning some of these swallows to population and therefore in separating some of those species in 'lookalike' categories (hence the interest this year). Both Grey-throated Sand Martin and Striated Swallow conform nicely to a 'southern' set (which also includes Pacific Swallow) which breeds early and completes its respective moult (including the post-juvenile moult) early (long before winter). It seems highly likely that there may be no overlap in timing of moult between birds in this southern set and those in the 'northern' (migratory) set (juveniles of which migrate in juvenile plumage and do not start their primary moults until winter). However, Striated Swallows still require further scrutiny to check for outliers. Difficulty in ascribing age to Riparia martins might also pose big problems for this hypothesis (as might my underlying assumption that Pale Sand Martin will belong to the southern set). Above photos taken in Tainan City 17-18/8/19.

Thursday, 15 August 2019

Adult Red-necked and Little Stints

Year in, year out, I spend all of August flogging the returning stints hoping for something with a Nearctic flavour, and year in, year out, the best I can come up with is Little Stint! Sometimes these prove easy to photograph (in which case I'll sit in the mud with them all day long), but regardless they invariably stick out like a sore thumb! Red-necked Stint may complete its moult into winter plumage earlier than does Little, as many individuals are already in an advanced state of moult (effectively in winter plumage) in August. Until they drop the outermost primaries (producing a short rear end), they differ structurally from Little in being longer-bodied and somewhat 'boat-bottomed' (i.e. there's plenty of body behind the legs which tapers gradually towards the tail tip on a side view). They are also 'flat-backed' in comparison with Little, with the back generally kept horizontal (or close to it) when pottering around. The typical feeding action differs from Little, with Red-necked extending its neck forwards to pick at objects (with the back kept horizontal), rather than tilting the whole body forwards. At such a time, the head looks large (and 'bull-naped') and the extended neck leaves a distended belly behind it, giving Red-necked Stint a distinctly pot-bellied appearance!

Adult Little Stints retain extensive traces of summer plumage well into August and presumably moult later than do Red-necked Stints. Unlike 'fatty' Red-neckeds, they are a delicate affair, being nothing more than a ball of feathers on spindly legs with a decidedly short rear end (i.e. what body there is behind the legs tapers abruptly towards to the tail tip). They are 'hunch/rounded-backed' in comparison with Red-necked, and the typical feeding action involves the whole body being tilted forwards with the neck retracted. When feeding, the rear end gets raised high into the air (you get 'mooned'), with the body reaching around 45° to the ground. If the neck is extended, the head is quite small (and 'square-shaped', lacking any 'bull-naped' quality). To my eye, Little Stint has more in common structurally with Long-toed Stint than it does with Red-necked Stint.

Little Stint vs. Red-necked Stint is repetitive stuff, I know, but the mega I'm anticipating continually refuses to appear! As these are easy to photograph, they hold my attention, when that at this time of year might best be directed elsewhere! Above photos taken in Tainan City, 14-15/8/19.

Saturday, 10 August 2019

Soggy Subic Bay

It was looking like I wasn't going to get away at all this summer, but then Air Asia opened a new route to Clark in the Philippines from just down the road in Gaoxiong and Subic Bay came onto the radar. Although it would be the wrong time of year to visit there (wet season), the flight costs were so incredibly low that it was not really possible to turn them down and I decided I should risk it anyway. With Da Chiao Lin also 'in', that made two for the trip and the trip became a 'go'. As expected, we did suffer at the hands of the weather, losing fully half of the week due to (oftentimes torrential) rain. A further minor inconvenience was the requirement that we first obtain 'clearance' (i.e. a permit) for birdwatching, which we had to get from the Ecology Centre downtown. As it turns out, a permit is needed to go birding anywhere in the SBMA area (not just Hill 394 as is generally known): this even includes from public roads in Upper Cubi (where we got stopped by police twice). The information here is accurate at the time of posting and it is possible to walk in off the street and apply for the permit in person (it takes about half an hour to process). The information on the Birding2Asia site (here), the 'go-to' site for Subic Bay, otherwise remains accurate, right down to the particular building you need to visit (i.e. the administrative building next to Subic International Hotel on the corner of Rizal and Labitan Road (labelled 'Visa Processing Office' on Google Maps)). However, it is also a source of confusion as you do not get the permit from the Tourism Centre as is stated there (this is in a different building), but from the Ecology Centre (which is on the ground floor of this building). One big positive from the trip was the accommodation we stayed in (here). This was ideally situated and had a number of noteworthy species (Luzon Hornbill, Blue-naped Parrot, Bar-bellied Cuckooshrike, Blackish Cuckooshrike, Stripe-sided Rhabdornis) visiting the trees around it, all of which could be viewed from out of the rain!

Having already been there before and expecting at least some rain, my ambitions for Subic were limited to getting decent photographs of some of the more common endemic species in that area. However, the rain brought with it some quite awful lighting, and I would not say that I necessarily succeeded in this unambitious task! The set I had the biggest interest in was the cuckoos (Philippine Coucal, Rufous Coucal, Rough-crested Malkoha, Scale-feathered Malkoha), and I did at least get record shots of all of these (with all but the last one being encountered fairly frequently).

I also managed to get all the parrots, but was left heartbroken when I found two very close Green Racquet-tails along the road to the hospital the very second it started to throw it down! A couple of Guiaberos on Nabasan Road were found in better conditions and proved very entertaining to watch! The only perched Philippine Hanging Parrots we found were also along the road to the hospital, but high up in a dead tree. I left it until the last morning to try and photograph Blue-naped Parrot in Upper Cubi, when perhaps unsurprisingly it also chose to throw it down!

Luzon Hornbills were frequently encountered and in some cases proved approachable. The lighting was generally off when birds were close, though, meaning potentially sharp shots turned out grainy.

A big bonus right in front of the Garnet Building in Cubi was a low Stripe-sided Rhabdornis. This was probably the one endemic I got the best shots of the whole trip.

I also managed to collect all the woodpecker 'set' (White-bellied Woodpecker, Northern Sooty Woodpecker, Luzon Flameback, Philippine Woodpecker) at Subic. These all proved to be common, but rarely came close. As with the Raquet-tails, my closest Northern Sooty Woodpecker was threatening to emerge from a dark patch of forest just in front of me right at the moment it chose to throw it down, leaving me an insufficient amount of time to adjust the settings on my camera!

Both cuckooshrikes proved easy to find around Subic: Bar-bellied Cuckooshrikes were remarkably common and in evidence wherever we stopped; Blackish Cuckooshrikes, though scarcer, were still encountered frequently. The bizarre-looking Coleto was perhaps the most conspicuous bird around Subic. Balicassio was also frequently seen at the roadside.

Perhaps the largest 'set' to collect at Subic is the pigeons. Most of these are rare, but Green Imperial Pigeon and Philippine Green Pigeon ought to be straightforward on any visit (though on this trip the latter did prove tricky). The most heartbreaking moment of trip for me was when a Yellow-breasted Fruit Dove chose to perch at range and in the most awkward light, meaning awful grainy photos once more. For me, this is perhaps the most attractive species to occur at Subic!

I did also manage to collect all of the commoner raptors at Subic, though these seldom took to the wing in the wet conditions. A flyby White-bellied Sea Eagle at the bottom of Nabasan Road was the most unexpected of these. Philippine Serpent Eagles were seen on occasion but were generally distant. Luzon Hawk Eagles, Brahminy Kites, and Philippine Falconets were more regularly encountered, but once again were very difficult to capture.

Other birds dotted around were Whiskered Treeswifts, Purple Needletails, and Brown-breasted Kingfishers. Like everything else here, these all selected areas with grey, featureless backdrops!

The only birds to buck the trends at Subic and show well was a family group of Barred Rails. These appeared in a small pond at the bottom of Nabasan Road, surrounded by colour and against a lush background, giving me at least some photos I could return home happy with!

Almost no animals were seen all week, other than the fruit bats in the roost just below Cubi and the odd Water Monitor. I guess what can be eaten here has been at some point in the past!

I would describe the week's birding we had at Subic as 'acceptable' as I had been expecting to lose at least some time to rain at the outset. Nothing unexpected or particularly rare was seen, though, and a gaping hole was left by night birds. All the failures this time round were a direct result of weather: it was not possible to hike the trail behind the hospital in the direction of Hill 394 due to fallen trees (hence specialities like White-lored Oriole were never going to make it onto the list), extended periods of time were lost when the rain became torrential (an entire day at one point), and most of the images I managed were grainy, underexposed, or just generally disappointing. As is shown above, though, the expected 'set' at Subic is still easy to collect, and the trip was still worthwhile in spite of the conditions. A visit in the dry season would add more, though, and provide better conditions for photography and birding in general. Above photos taken in Bataan Province, Philippines 2-8/8/19.