Peculiar Behavior of Aerodramus Swiflets

Introduction

The study of natural history or life sciences unlike Engineering or IoTs courses involves many hours in the field. Some even took years like Alfred Russel Wallace before they can really understand Natures' behavior. The good thing about this (i.e spending your free time with Nature) is that you can understand or discover some moments which your books, field guides, teachers or sifus will not be able to tell you. Recently i came across what i believe was a very peculiar feeding behavior of some 'Aerodramus Swiflets' or locally named 'Burung Layang Layang' or 'Burung Walit' in Indon.

Observation

According to the field guides, there are several "Aerodramus Swiflets" which can be found in this region. From the common Germain's Swiflets and 'Edible-Nest Swiflets' to the less common 'Himalayan Swiflet'. While on a casual birding trip (up North) in December 2016, i came across some swiflets flying over head. While taking some photos of them i noticed one photo which appears kinda different from the rest. Have a look below:

Image 1: 9.02am

You may have also probably seen or photographed a swift with a bulge at its throat area like the one above. I have also read comments from birders who thought that it could be some kind of a "growth" (a diseased bird !). Initially i have the same thoughts but after seeing a few other swiftlets having similar features, it aroused my curiosity to investigate further. I went on to snap a few more photographs of the swiflets to compare their images. The result of the comparison produced some astonishing discoveries ! Have a look at the photos below of other swiftlets with similar feature which were taken at different intervals on the same day of observation:

Image 2: 9.19am

Image 3: 9.42am

Image 4: 9.48am

Image 5: 9.50am

Image 6: 9.54am

Image 7: 10.02am

Discussion

All the above photos depict different individuals. Most of them have some bulging throat except the birds in image 6 and 7 while the bird in image 4 has the largest bulge. They were all seen flying just above some secondary jungle behind a housing estate in Kedah, West Peninsular Malaysia. You may have also noticed that there were different sizes of bulge which appears smaller in the later morning as shown in image 6 and 7. Most of the swiflets have dispersed from the sky by 11.00am. This incidental discovery have raised the following questions that needed further investigation:

i) Did these swiftlets intentionally kept their food inside their throat while slowly devouring them in flight?

ii) Did they kept their food inside their throat so that they can bring it back to feed their fledgling in the nest?

iii) Was this phenomenon universal or was it just a one-off event?

Summary

Image 8: a swift having its meal (a butterfly) in flight

From the above observation, there is no doubt that these swiflets are not diseased birds. As swiflets were known  as insectivorous and consumed their meal in flight, there is a high possibility that these swiftlets might have kept their food in their throat. The smaller size bulge towards the later morning could be due to the lack of airborne insects as the day gets hotter or they may have consumed them. So far i have not been able to find any accounts and literature discussing such behavior in the internet todate. Could this be a new discovery which may one day prove a valuable data of a scientific significance? Only time will tell ! I hope more birders can report their findings (if any) so that this observation can be further validated.

....until then 'HAPPY BIRDING' !

Note: finally i found some info on the above feeding behavior which vindicated my observation and answered all the above questions. Here is the info taken from RSPB website:

"As the bird is hunting, insects are collected in the back of the throat in a special food pouch and bound together with saliva into a ball called a bolus, which is periodically eaten or taken to the nest. These food balls can contain thousands of insects"

Amazing !

Birding in Mount Kinabalu National Park - Dec 2016

Introduction

Mount Kinabalu has long been heralded as one of the best birding site for montane birds in this region. My day finally came on 15 December 2016 as i took a lone trip up to this mountain with only one aim i.e to see as many birds as i can within 4 - 5 hours of birding time. For your comfort, it is advisable to rent a car which is only around RM130.00 to RM180.00 per day (i.e depending on the type of vehicle you drive). All you need is a valid driving license, some sense of direction and a good cup of tea/coffee.

According to the folklore, the name "Kinabalu" actually came from the word "Nabalu". In fact you can find a town called "Pekan Nabalu" in Kundasang on your way up to the mountain. It was believed that a widow who is so aggrieved that she has turned herself into a mountain and local folks here believed that her tears can still be seen from this mountain until today. Aside from this legendary tale, Mount Kinabalu has a rich biodiversity that some of its birds can only be found here and no where else!

The above photo was taken from Pondok Timpohon (Timpohon Gate) which is about 1,866 meters asl. What a magnificent view!

Getting ready to summit.

Here are some potters getting ready to bring up food rations to "Laban Rata Resthouse' which is supposed to be a "base camp" before the final ascend to the summit. Its another 4 km from the 'base camp' to the summit as i was informed. These potters were mainly young adults. I did saw a lady potter as well among the crowd. There were hardly any climbers around as they would have probably hiked up by the time i arrived at the gate. The potters don't look that stocky but they are certainly as tough as a nail ! Just look at their calf muscle which developed from climbing up and down at least 1 - 2 times a day for some. 

The Beginning of My Birding Adventure (Timpohon Gate)

I started birding at 8.15am literally from Timpohon Gate. Due to time constraint i have only concentrated on 3 main trails i.e "Liwagu", "Bukit Ular" and "Silau Silau". Weather was cloudy with some sun rays shining thru occasionally in between them. It was indeed a pleasant weather with temperature around 20 - 22 Celsius in the early hours of the morning. I guess i was very lucky as it did rained in this mountain just a few days before.

Bornean Whistling Thrush

This was the first range restricted endemic bird which came out to greet me. It hop and hop towards a certain direction as if it wish to show me something. I followed the bird and indeed it lead me to my first trail of the trip - the "Liwagu Trail" ! I spent close to 2.5 hours at this place. In fact most of the birds seen in this trip were spotted at this location.

The markings says the trail is 5.620 meters to the HQ. Sure or not ? Most current information states that Mount Kinabalu is only about 4,095 meters / 13,435 feet asl.  I birded the trail to about 400 to 500 meters below which reminded me of the "Pine Tree Trail" of Fraser's Hill. Climbing up the trail was another story - i nearly fainted. Here are some of the birds which i have manage to photographed along this trail as i panted away while some "smoke" can be seen coming out from my mouth:

Bornean Treepie

This is a montane bird which can be found only in Borneo.

I believe the above bird is also a Bornean Treepie.

Bornean Whistling Thrush

This is probably the same individual which lead me down the trail. Its flight was abrupt and it did not whistle at all. Despite all the description given by the books, its overall plumage looks dark in most photographs. It is clearly distinguishable from the "Malaysian Whistling Thrush" which appear more bluish (feathers) and yellow (bill).

You can clearly see its hooked bill which is used to get worms and insects from the forest litters as reported by some books and literature.

Yellow-breasted Warbler

This warbler can also be found in Fraser's Hills but over here it was much easier.

Bornean Mountain Whistler

This "Bornean Mountain Whistler" is another range restricted endemic bird. What a great opportunity to spot this bird !

Here is another bird which can only be found in this region:

Chestnut-crested Yuhina

It appears like the population of  "Chestnut-crested Yuhina" is more than the above "Mountain Whistler" (as observed).

There were also some Peninsular Malaysia birds seen here:

Temminck's Sunbird

Blyth's Shrike Babbler

The existence of a few Peninsular Malaysia birds in Borneo may have supported the theory that Borneo was once part of a supercontinent (pangaea) which eventually broke up during the late Mesozoic period.

An experience birder who is familiar with this area reckoned that this flycatcher was a female 'Pale Blue". Looks good to me as well.

Any objections?

The Bukit UlarTrail

I begin my descent at 11.00am and the next trail i came across is the "Bukit Ular Trail". This trail reminded me of the "Bishop Trail' in Fraser's Hill.  It was quite steep at some places and slippery as well. Probably due to the overnight showers. I only went about 50 meters inside the trail. Due to its thick vegetation and dense canopy, photographing birds can be a challenged inside this trail.

Bornean Mountain Squirrel

Looks more like the Ssp: Dreamomys everetti?

Here is another mystery bird:

Could this be a Sunda Cuckoo / Banded Bay Cuckoo?

The bird below is more distinguishable:

Sunda Bush Warbler

Its buffish brow and pale legs are diagnostic and should separate it from the more elusive "Friendly Bush Warbler".

Thanks mate for showing your butt !

This Bornean Whistling Thrush was not calling but was seen expelling some things from its throat (as observed).

Some birds can be seen from the road side as well.

I think the bird above could just be a female mountain leaf warbler although a male Black-sided Flowerpecker was also seen nearby but kept himself in the thick foliage.

Little Pied Flycatcatcher

It certainly has a very broad/thick brow.

Many birds here have bands on their legs. Saw one Grey-throated Babbler with a metal band as well. Despite so many leg bands, there are still little info/literature available on some of these birds.

Cute little ones.

Silau Silau Trail

There were several unmarked trails along the way before "silau-silau" but since i was not familiar with them, i just skipped those trails. Most of the trails were peaceful and void of humans which make me wanted to run naked inside those trails. But then i was afraid that the Mountain GODS may not like what they see ! Further more i do not wish to cause another earthquake in Ranau. As i descent further down, there were less birds seen. Most of the birds on this trip were confined high up on the tree tops.

This Gray Wagtail  in contrary, was not too shy to show itself by the roadside.

Gray Wagtail

Finally i reached the 'Silau-Silau' trail.

One of the most decent trail you can ever find here. It was well kept and it looks just like your garden. Things were quite quiet inside this trail though, probably due to the fact that it was already 12.45pm when i reached here.

Mountain  Leaf Warbler

This warbler was seen at the roadside and not inside the trail. There are no photo editing software in the market that could ever change the color of its plumage. This is the Ssp: Phylloscopus trivirgatus kinabaluensis.

There were a few of them foraging just above me.

Liwagu Restaurant to Park HQ

By the time i reached here, i have covered almost 4.5 km. I wished i could just roll down the mountain like humpty dumpty. I can see my legs behind me as they have refused to move. Then came a nice Liwagu restaurant staff (a lady) who pointed to me and said "itu helang kan?" (is that an eagle?). Unfortunately i have forgotten her name but i wished to thank her for spotting this uncommon raptor for me. 

Rufous Bellied Eagle

This was a subadult Rufous Bellied Eagle as pointed out to me by local birding experts. This eagle usual breeding season is reported to be from November/December.

It was seen circling around and did not utter any calls. Suddenly it moved its tail left and right as though it wish to say goodbye to me (see above photo). The mountain Gods must have sent it down to wish me "Au Revoir".

It then flew across for one last time as it headed back to the mountains.
Note: the last official sighting record in this location was in 1984 (ref: eBird data).

As i reached the HQ area,  i saw several swifts flying overhead.

Glossy Swiflet

They turned out to be some glossy swiftlets, as depicted by the light green sheen on its back which can be seen from the above photo.

Another feature is that its throat and breast area is more brownish and have darker shaft streaks as shown from the above photo.

The final bird seen was this "Ashy Drongo". 

Ashy Drongo

There were a few variants as described by the literature and from the color of its face features, this Ashy Drongo is probably not a migrant. Interestingly this drongo was not spotted at higher altitude, for example at the "Liwagu trail". 

Summary

I also saw a few birding couples mainly foreigners who were busy looking for birdies too and if you happened to be a spouse to one, here are some interesting books which you might want to bring along during a trip with your spouse:

On the 1st day of the trip

Try reading: "After You" (by Joyo Moyes)

On the 2nd day of the trip

Try reading: "The Missing Husband" (by Amanda Brooke)

On the 3rd day of the trip

Try reading: "I Sold Your Ferrari" (by Robin Sharma) - pun intended !

Despite my aching muscles and the fact that i missed out on several common resident birds such as "Indigo Flycatcher", "Mountain Blackeye", "Golden-naped Barbet" (despite calling just above my head), and the much sort after "Whitehead's Trogon", "Fruithunter", "Mountain Blackbird", "Whitehead's Broadbill", "Everett's Thrush", "Crimson-headed Partridge" etc, overall it was an amazing trip. I saw and heard a total of 22 bird species with several remained unidentified.

That was my story and birding adventure at this majestic mountain. 

HAPPY BIRDING ! 

Bird Watching Near Bedong Raptor Site - Sept 2016

When i was young i have always thought that the world will have seamless boundaries which one can never ever see but as i grow older i realised that the world is actually much smaller and getting smaller by the day. There were recent reports that Australia is slowly inching its way further north. This means that one day we will have cassowaries, kangaroos, koobaburras etc at our door steps. The unfortunate news is that this will only happen in about a million years from now. While waiting for that to happen, i have recently done a bit of bird watching near a town called Bedong in the northern state of Kedah. What was supposed to be a casual and relaxing event has actually turned out to be an interesting if not a significant trip. As the saying goes "Some of the Greatest Discoveries in Science Were Found by Accident"

The first day of a few trips to this area started as early as 6.45am on 12 September 2016! Heard a few calls from a nightjar which i believe it came from the most common nightjar in town which is the "Large-Tailed Nightjar" (Caprimulgus macrurus). From where i stood, i could also hear thunders roaring and lighting flashing from a distance.

This was the first significant find on the first day. An adult male Japanese Sparrow Hawk (Accipiter gularis). It was spotted gliding just over the tree top at 9.40am. 

A local and an international raptor expert from Thailand was kind enough to confirmed its identification for me. (Note: its lack of a clear mesial streak). This sighting according to the expert is consistent with the early arrival of raptors in mid September (autumn migration). I was indeed delighted to be able to contribute some data to the local raptor records.

(Note: Despite its arched wings which is a typical flying posture of a raptor on cruising mode, it was however not as fast as the Peregrine Falcon. Despite that i was just able to take two decent shots of it)

Here it is again flying southwards. With its wings spread out wide, this raptor was gliding slowly to its winter ground which is reportedly to be at the neighboring country of Indonesia.

The second significant sighting was the arrival of the Oriental Honey Buzzard (OHB).

Unlike the above A. gularis, this adult male orientalis OHB was cruising from east to west as can be seen from the above photo. This OHB was spotted on 15 Sept 2016 at 10.32am.

Here is another image of the OHB which was spotted just above the tree top as well.

I was curious to know why these two raptors were flying so low during their migration and i have only these hypotheses to describe the phenomenon:

i) Despite reports that thousands of migrant raptors have already appeared in Khao Dinsor at that time, i doubted the above birds of prey have flew in directly from that site. Weather conditions in the northern region at that time were not conducive enough for an early morning lift off. So the most likely reason was that the raptors have stayed at a nearby staging area overnight before it took off.

ii) The second reason could be that they may be looking for prey in the morning while waiting for the thermal to built up.

Aside from the above raptors, other common migrant birds were also spotted. All of them were flying southwards.

Looks more likely to be called a forked-tailed bee eater from this image but this bee-eater was a Chestnut-Headed Bee-Eater (Merops leschenaulti).

Despite these single photos seen here,  they were actually travelling in a flock of 4 - 5 birds at a time.

Here is another bee-eater which is heading towards the same direction.

Blue-tailed Bee Eater (M. philippinus)

Some of them were also observed thermaling high up in the skies like some raptors.

From where i hide which was under a 'dokong' tree (bukan dugong lah !) which was facing an old durian tree, my views were only confined to 180 degrees. So when a flock of 7 - 8 Daurian Starlings (Sturnus sturninus) flew by, i have only enough time to take a photo of its two trailing members as depicted above. They are really fast flyers.

This is a "Barn Swallow". A very common winter visitor which is an early arrival too. Their numbers were just a handful as compared to the more common "Collocalia" species. In the field, you can identify 'Barn Swallows' from 'Collocalia' species in flight by looking at their wings. In flight 'Barn Swallow' wings are usually folded way back which makes them resemble an arrow head. To illustrate the arrow-like head profile in flight, here are some its photos taken in Nov 2016: 

The above two photos were taken in KL.

This is a rather peculiar looking "Collocalia' species which face area is white. Saw a few of them with similar features.

An interesting wing profile of a "Collocalia". I think some air force could consider using this as one of their insignia. Their numbers have significantly increased but from my personal field observation, their numbers will peak in the coming months of January to February where you can observe them in thousands from this area. These swiflets fly out as early as 6.50am (personal field observation).

Here is another swiftlet with a peculiar looking bulging mouth area. I believe i have made some significant discovery to explain this bulging feature which i will share in my future posting soon.

Another peculiar looking swiflet of an unknown origin.

The local common birds were equaling stunning. Here are just some of them.

A squadron of herons flying southwards in a tight formation in the early hours of the morning. I believe they were "Black-Crowned Night Heron" (Nycticorax nycticorax).

The above photos actually depicted two different adult Brahminy Kites. I found it really hard to describe their differences except for some of its underwing features.

A flock of Asian Glossy Starlings flying in the opposite direction.

This "Common Iora" was looking at me one kind just like some passer by.

 A splendid looking male "Olive-Backed Sunbird"

......and his equally stunning girl pal.

Have you seen a Pied Thriller (Lalage nigra striga) often before? Neither did i.

Quite a stunning species if you asked me.

Here is how it looks like from the back.

I believe this was just a common female "Pink-necked Green Pigeon".

The butterflies down here is equally stunning. This is a "Lemon Pansy" (Junonia lemonias) which are reportedly common only in the north-west of Peninsular Malaysia.

Nocturnal creatures are both mysterious and difficult to observe. That is why they are often understudied and intriguing. As dusk falls, out came these bats which i believe were just some common fruit bats.

Batman is calling you to Gotham City!

HAPPY BIRDING WHEREVER YOU ARE !