Blurred Lines: Navigating the Space Between Native and Non-native

The Asian Koel is today one of Singapore’s most numerous urban species, but did you know that it was previously only found as a migrant?

The Singapore Birds Project recently participated in a conference organised by the Asia Research Institute, National University of Singapore (ARI, NUS). Titled “Learning from Aliens: New Directions in Environmental Humanities Research and Practice”, speakers from numerous fields extending from science, history, to art and poetry shared their perspectives on “aliens” in biodiversity settings. During the conference, Keita and Movin shared about birds in Singapore and discussed the complexities of classifying “non-native” and “native” species in the highly modified local landscape. The Asian Koel’s history in Singapore is also covered. We’ve uploaded our talk on Youtube so do check it out if you were unable to attend!

We would like to extend a massive thanks to everyone from ARI and Yale-NUS who organised this event, all the speakers for the insightful perspectives, and most importantly Anthony for inviting us. We’re also looking forward to future collaborations 🙂

ARI is organising an upcoming conference on Singapore’s Biodiversity History that you can attend for free (either in person or via zoom) on 13 and 14 July. More information can be found here! The Singapore Birds Project will not be a part of this but established speakers from various fields will be there, so do check it out!

FLY201: An overview of brown flycatchers in Muscicapidae

ID Articles

Despite the brown and drab appearances of many species in the Old World flycatcher family (Muscicapidae), these birds are (surprisingly!) adored by many. Their large eyes, friendly demeanour, and exciting hunting behaviour make them great candidates for birdwatching and photography. However, the identification challenges presented by these “little brown jobs” can throw even the most experienced birders off. In this article, we will share pointers on how to identify some of the flycatchers that reach our shores.

The majority of flycatchers found in Singapore are either non-breeding visitors or migrants. In some groups, adult males have extravagant breeding plumages with prominent features that make them relatively easy to identify. However, the identification of females and immatures are not as straightforward. This article focuses on distinguishing the different groups (or genera) of flycatchers—Muscicapa, Ficedula, Cyanoptila, and Cyornis. Once you are able to tell apart the different genera, it will help narrow down the possible choices and pin down the species!

Fig 1. Three different brown flycatchers—can you figure out who is who? Photo credit: Francis Yap

Muscicapa

List of species: Asian Brown Flycatcher, Brown-streaked Flycatcher, Dark-sided Flycatcher, Grey-streaked Flycatcher, Ferruginous Flycatcher, Spotted Flycatcher, Brown-breasted Flycatcher

For a more in-depth guide on this genus, check out our article here.

Members of this group can generally be told apart from other genera by their vertical perching posture and relatively large head with a big-eyed appearance. Both sexes are similar in appearance for the above-mentioned species within Muscicapa. One of our most common migrants in Singapore, the Asian Brown Flycatcher, falls within this group!

Fig 2. Asian Brown Flycatcher, Singapore. Photo credit: Francis Yap

Fig 3. Brown-streaked Flycatcher, Singapore. Photo credit: Francis Yap

Fig 4. Dark-sided Flycatcher, Singapore. Photo credit: Francis Yap

Fig 5. Grey-streaked Flycatcher, Singapore. Photo credit: Francis Yap

Among similar-looking species, Asian Brown Flycatcher has the most prominent white lores and eyering. For its underparts, it possesses smudged pale grey streaking on its breast and flanks, compared to a) Brown-streaked Flycatcher which has warm brown streaking for younger birds and indistinct greyish-brown streaking for adults, b) Dark-sided Flycatcher which has darker, more well-defined grey streaking, c) Grey-streaked Flycatcher which has the most well-defined grey streaks of all the species here, with streaks appearing distinct and pencil-like. Another way of telling Brown-streaked Flycatchers apart from the rest is through its warmer plumage and buff edges to coverts and tertials.

** Do note that underpart streaking is variable within each species.

Additional tips: Dark-sided Flycatchers typically have bills that look shorter and slimmer than the rest, appearing almost like a stub. On the other hand, Grey-streaked Flycatchers have wings that appears much longer than those of its friends, with its wing tips usually exceeding its undertail coverts (typically does not happen for the other two species) (Leader, 2010). See if you can spot these differences in the pictures above!

Fig 6. Ferruginous Flycatcher, Singapore. Photo credit: Francis Yap

The Ferruginous Flycatcher looks very distinct from the rest of the Muscicapa flycatchers in terms of plumage, leading to its nickname of Iron Boy locally! Its grey head contrasts with the rest of the rich orange plumage on its body, making this the most colourful species in this genus!

Fig 7. Spotted Flycatcher, Singapore. Photo credit: Francis Yap

One of the newest member of the genus that has been added to Singapore’s checklist—the Spotted Flycatcher can be distinguished by its buff lores and eyering along with a streaked crown.

Fig 8. Brown-breasted Flycatcher, Sri Lanka. Photo credit: Dillen Ng

Another vagrant flycatcher to our shores! At first look, the Brown-breasted Flycatcher is similar in appearance to the more common Asian Brown Flycatcher with its distinct pale lores, but can be separated by its larger bill, warm brown upperparts with rufous tips to tertials and coverts, less extensive dark tip to lower mandible, and pale yellowish-pink legs. Sounds similar to something else you just read? Bill size and leg colour also helps distinguish it from the Brown-streaked Flycatcher, which has darkish legs much like the Asian Brown Flycatcher. Lastly, the Brown-chested Jungle Flycatcher might also be another confusion species with its brown wash and pale legs, but the Brown-breasted Flycatcher generally has more prominent pale lores and contrasting upperparts, with its mantle being a richer brown than its head. The Brown-chested Jungle Flycatcher appears more concolourous overall with a consistent dull-brown wash and has a thicker bill. Lastly, the Ferruginous Flycatcher is much more vibrant orange with a smaller bill compared to the Brown-breasted Flycatcher.

Cyornis

List of species: Mangrove Blue Flycatcher, Chinese Blue Flycatcher, Brown-chested Jungle Flycatcher.

Fig 9. Male Mangrove Blue Flycatcher, Singapore. Photo credit: Francis Yap

Fig 10. Male Chinese Blue Flycatcher, Singapore. Photo credit: Francis Yap

Male Mangrove Blue Flycatchers and Chinese Blue Flycatchers have a stunning blue and orange plumage and can be separated from each other by the extent of orange on their underparts. The local subspecies of the Mangrove Blue Flycatcher (ssp rufigastra) has orange underparts that extend from its throat to vent and lack brown-washed flanks. In contrast, the Chinese Blue Flycatcher has an orange throat and breast that fades to white from its belly onwards, with brownish flanks.

Fig 11. Female Mangrove Blue Flycatcher, Singapore. Photo credit: Francis Yap

Fig 12. Female Chinese Blue Flycatcher, Thailand. Photo credit: Ayuwat Jearwattanakanok

The female Mangrove Blue Flycatcher is very similar in plumage to the male, but with white lores. While the female Chinese Blue Flycatcher has yet to be recorded in Singapore, it’s always good to be prepared for its (eventual) appearance! It can resemble a female Mugimaki Flycatcher with its dull orange throat and breast, but it is larger in size with a stronger bill, pale buff lores, and is much warmer in colour overall (especially in rufous tail and uppertail coverts)—features which are lacking in a female Mugimaki Flycatcher. The Chinese Blue Flycatcher also lacks wingbars (compared to the Mugimaki Flycatcher which does).

Fig 13. Brown-chested Jungle Flycatcher, Singapore. Photo credit: Francis Yap

Fig 14. Asian Brown Flycatcher, Singapore. Photo credit: Francis Yap

The most common member of this group, the Brown-chested Jungle Flycatcher, looks nothing similar to its close relatives in Singapore! Both sexes look similar and have a dull, warm brown plumage with a brown breast band. They have a large, hooked bill that is quite unlike the other flycatchers, and has a dark upper mandible and yellow lower mandible (dark tipped for first-winter birds), along with pinkish legs (Wells, 2007). This species likes to hang out in dense, low to mid-storey vegetation.

Cyanoptila

List of species: Blue-and-white Flycatcher, Zappey’s Flycatcher

Fig 15. Blue-and-white Flycatcher, Singapore. Photo credit: Francis Yap

Fig 16. Zappey’s Flycatcher, Singapore. Photo credit: Francis Yap

Males of these two species are popular with birdwatchers, with their brilliant blue and white plumage. The Blue-and-white Flycatcher has a blackish face and throat that contrasts strongly with the rest of its upperparts, while Zappey’s Flycatcher has a dark bluish face and throat that blends in more seamlessly with its upperparts. They generally perch upright.

Fig 17. Typical appearance of a immature male Cyanoptila flycatcher, Singapore. Photo credit: Adrian Silas Tay

Fig 18. Female Cyanoptila flycatcher, Singapore. Photo credit: Adrian Silas Tay

Fig 19. Asian Brown Flycatcher, Singapore. Photo credit: Francis Yap

Fig 20. Female Narcissus Flycatcher, Singapore. Photo credit: Francis Yap

While females and immature males in Cyanoptila cannot be identified to species level, immature (e.g. first winter) males typically exhibit some degree of blue in their tail, wings, and upperparts while retaining brown feathering on their head and throat, setting them apart from other birds. The trickier ones are female individuals, which can be told apart from other brown-looking flycatchers by the following features:

Larger in size compared to the other brown flycatchers, looks bulkier and longer in shape
Relative to overall body size, head and eyes are not as big as species such as the Asian Brown Flycatcher
All black bill that is short and thick; not hooked like Brown-chested Jungle Flycatcher, which also has a yellowish lower mandible.
Rump brownish and concolorous with upperparts, with rufous wash on uppertail coverts versus female Narcissus Flycatcher, which has bright olive rump that contrasts starkly with rest of upperparts and rufous uppertail coverts (Bakewell et al., 2021; Wells, 2007)
No dark streaking on underparts like Dark-sided Flycatcher or Grey-streaked Flycatcher

Ficedula

List of species: Yellow-rumped Flycatcher, Narcissus Flycatcher, Mugimaki Flycatcher, Green-backed Flycatcher, Taiga Flycatcher

Species in this genus also exhibit sexual dimorphism, with males being more colourful than females. Ficedula flycatchers typically perch in a more horizontal posture and have a flatter and elongated head shape compared to Muscicapa flycatchers (which perch vertically and have a more rounded head).

Fig 21. Male Yellow-rumped Flycatcher, Singapore. Photo credit: Francis Yap

Fig 22. Male Narcissus Flycatcher, Singapore. Photo credit: Francis Yap

Fig 23. Male Mugimaki Flycatcher, Singapore. Photo credit: Francis Yap

Fig 24. Male Green-backed Flycatcher, Singapore. Photo credit: Francis Yap

Fig 25. Male Taiga Flycatcher, Thailand. Photo credit: Ayuwat Jearwattanakanok

While males are generally rather distinct from each other and will not be covered in detail here, there are still possible mix-ups! The male Yellow-rumped Flycatcher can be confused for the rarer Narcissus Flycatcher on first sight—but the former has a white supercilium with bright yellow throat and extensive yellow underparts, while the latter has a yellow supercilium with a dazzling orange-yellow throat and yellow underparts that are usually less extensive. In contrast, male Mugimaki Flycatchers have much deeper orange underparts and a limited white supercilium compared to the two above, which typically have more yellow underparts (with orange concentrated in the throat area). Male Green-backed Flycatchers look quite distinct from the rest of the males in this group, with an olive mantle and head plus yellow underparts and rump. The orange throat for male Taiga Flycatchers is much more limited in area compared to female Mugimaki Flycatchers.

Fig 26. Female Yellow-rumped Flycatcher, Singapore. Photo credit: Francis Yap

Fig 27. Female Narcissus Flycatcher, Singapore. Photo credit: Francis Yap

Fig 28. Female Mugimaki Flycatcher, Singapore. Photo credit: Francis Yap

Fig 29. Female Green-backed Flycatcher, Singapore. Photo credit: Francis Yap

Fig 30. Female Taiga Flycatcher, Singapore. Photo credit: Francis Yap

On the other hand, females can be confusing to tell apart (again!) but fortunately, each species has their own distinct features.

The Yellow-rumped Flycatcher is the only female with a bright yellow rump; the presence of a white edged tertial and lack of rufous tinge to uppertail coverts and tail are also useful for identification.
The Narcissus Flycatcher is typically a lot duller in colour, with whitish underparts and browner upperparts (vs olive of Green-backed Flycatcher). Differences with female Cyanoptila flycatchers are elaborated in the previous section.
The Mugimaki Flycatcher has an orange throat and breast that separates it from the others.
The Green-backed Flycatcher is generally the most yellowish in appearance, with light yellow underparts, yellowish lores and eyering along with an olive mantle. In particular, its rump is more concolorous with the rest of its upperparts, with olive-brown uppertail coverts. The rump is generally not as contrasting with the mantle/uppertail coverts compared to the Narcissus Flycatcher, which has an olive rump that stands out more against its duller mantle/rufous uppertail coverts) (Bakewell at al., 2021).
The Taiga Flycatcher is rather unique in its behaviour as it likes to continuously flick its tail up and down, with its tail often placed in a “cocked”, horizontal position (as opposed to pointing downwards like in other flycatchers). However, do note that other flycatchers can exhibit this behaviour as well (e.g. Asian Brown Flycatcher) so this is not an entirely diagnostic trait. Plumage-wise, it has prominent black uppertail coverts and tail.

And that’s it for this guide, hopefully this will aid you in identifying some of these little brown jobs that are found in Singapore!

Big thanks to Keita Sin, Raghav Narayanswamy, and Movin Nyanasengeran for helping to review the article and Francis Yap, Adrian Silas Tay, and Ayuwat Jearwattanakanok for providing their excellent photos for this guide!

All photos annotated by Dillen Ng.

Answers to Fig. 1: Asian Brown Flycatcher, Brown-chested Jungle Flycatcher, Brown-streaked Flycatcher (from top to bottom)

References:

Bakewell, D. N., Round, P. D., Jearwattanakanok, A., Eaton, J. A., Park, J. -G., & Shigeta, Y. (2021). Identification of the narcissus flycatcher−yellow-rumped flycatcher complex in subadult and female plumages. BirdingASIA, 36, 22–34.

Leader, P. J. (2010). Brown, Siberian and grey-streaked flycatchers: identification and ageing. British Birds, 10, 658–671.

Wells, D.R. (2009). The Birds of the Thai-Malay Peninsula, Volume 2, Passerines. Christopher Helm.

RAP301: What is that raptor?

ID Articles

By Max Khoo

There I was standing on Henderson Waves on a Saturday in October 2020. The sky was blue, the sun was scorching, and the bridge was packed full of big-name bird watchers and photographers. My friend and seasoned bird watcher Bryan Lim had invited me to join him here to catch the annual autumn raptor migration, but I arrived early. It was my first time here and I did not know anyone else. So, I found an empty spot by the corner of the “main pack” and avoided all conversations. The show had already started when I arrived: Birders pointing into the sky every few minutes, seemingly random, and screaming out names, abbreviations, and acronyms that sounded so alien to me. “Accipiter, above the DSTA building!”, “OHB, 12 o’clock!”, they hollered. I felt terribly lost. It was not only a challenge to spot the birds, but it was even more challenging to identify what species they were. Most of the birds were flying several to tens of kilometers overhead. They were small, and the rays of the sun shining on them makes it so that you can only see the birds’ silhouette most of the time. The birds all looked the same to me, and I was afraid to ask the very knowledgeable people around me as to how each bird was identified as I was scared to take up their time and too ashamed at my shallow knowledge. The three hours went by really quickly that day, and although it was utterly overwhelming, I was so captivated by the spectacle of flocks and birds flying past us continuously.

Raptor watching is not easy. The barrier to entry is high, and it is often said to be only for the “serious” bird watchers because identifying the birds is difficult. But it does not have to be this way, and I believe everyone can do so and enjoy the process. The two blog posts introducing the common and uncommon raptors of Singapore (RAP101 and RAP201) by Sandra Chia of the Singapore Birds Project team have helped me tremendously when I went back to catch the raptor migration for the second year in 2021. Based on the two posts, I had the idea of consolidating all the information together into a single-page guide so that it is even easier for anyone to refer to. So here it is, introducing the field guide to identifying raptors in flight based on its silhouette titled: “What is that Raptor?”. I hope this will serve as a useful resource for all who would like to pick up raptor watching, and even for the veterans who may want to brush up their knowledge before the annual raptor migration season.

PDF for download here.

My Accidental Sprint Year

Blog

Written by Max Khoo

If you asked me a year ago in November 2020, I would have told you that I’m a photographer and not so much a birder. Well, I could identify the common garden birds, but saying I could confidently identify anything beyond that would be a stretch.

I know many who got into birding as a hobby (or obsession) because they were first mesmerised by a particular colourful bird or an interesting behaviour of a bird. However, what really got me started birding seriously in 2021 wasn’t really about the birds. It was about the sense of exploration, the wondrous feeling of being outdoors and surrounded by nature, and the need to escape somewhere during my free time due to an especially stressful start to the year at work. I give all credit to the transient ponds of the now-gone Neo Tiew Harvest Lane that ignited that spark in me. That place was magical at sunrise: Chilly air filled with the dawn chorus of birds, with not a single building or soul in sight, and the birds just happened to be there and I really wanted to know what they were. Whenever I was there, I felt like I was transported overseas and free from any worries.

20 Dec 2020 – Neo Tiew Harvest Lane. These ponds were created as part of the land preparation works before the agricultural farm that now sits atop them were built.

Since I was already spending my weekends outdoors exploring places like Neo Tiew Harvest Lane, I decided to take birding a bit more seriously, with a methodical approach. The eBird app helped me do just that, allowing me to diligently record all my trips and sightings. The species write-up pages of the Singapore Birds Project were also like my bible, where I constantly referred to them to check if I was identifying a bird accurately.

Heatmap of the birding sites I visited in 2021. As I recorded most of my birding trips on the eBird App this year, I could extract the information and see which sites I visited the most. No surprise that Marina East, my current favourite birding site, came out on top.

In the first half of the year, I was birding at my own pace. I went birding alone, and visited where I felt like rather than twitching (exceptions: when the extremely rare Green Broadbill and Black-thighed Falconet were sighted) or heading to sites where I could see some birds that could only be seen during a particular time of the year. Towards the second half of the year, my good friends, seeing that I have seen a good number of species so far, began seeding the idea that I should do a ‘big year’ (this involves the ‘simple’ task of seeing as many species as possible in a year). As generational talent Albert Low puts it, I resolutely refused this idea for various reasons. I never felt like I was good enough and ready to do it since I just started my first proper year of birding, and I’ve already missed many rare birds early in the year (e.g. rarer resident birds that are easier to see during the breeding season; seabirds along the Singapore Straits on pelagic trips). But perhaps it was my love for challenges (challenging myself to become a better birder, as well as to see if I could claw my way up and catch up to Jen Wei (fellow big year birder) who was leading by leaps and bounds at that point) and the pandemic (when else would I be stuck in Singapore for almost the whole year?!?) that I decided to commit to this mammoth task starting September 2021. From here on, my accidental sprint year was born, with an initial target of trying to reach 220 species.

There are too many stories of this accidental sprint year to tell. However, one of the most memorable would definitely be making more than 5 trips at the start of September, trying to see the lone Greater Sand Plover amongst the rest of the Lesser Sand Plovers at Yishun Dam, and finally deciding to give up (and be at peace with it mentally) after I walked away from Yishun Dam on the fifth trip. In the end, I managed to see the bird atop floating solar panels in the reservoir beside where my car was parked, away from where it would normally be, and this was what really gave me the push and confidence I needed for the sprint. The remaining of the four months was a whirlwind of trying to chase every passage migrant, twitch every rare bird like a crazy headless chicken, and visit many new places in Singapore that I never knew existed. Along the way, some birds were easier seen than others where oftentimes I got really lucky, while some eluded me even after I tried my best.

Can you spot the Greater Sand Plover (my 191th bird of the year) amongst the Lesser Sand Plovers? Check below for the answer! I dedicate this species as my bird of the year not only due to the time I spent trying to find it, but how it was a technical challenge for me to identify it in the field: I could not sit around and wait for the bird to appear as it could be right in front of me amongst the tens/hundreds of tiny Lesser Sand Plovers that frequent the mudflats, and I had to know the features well enough to be able to distinguish the species in the field.

Click to reveal where the bird is hiding!

Fast forward to the last week of December, I managed to tick 4 new species by 30th December to reach my 266th bird, way beyond my initial target. However, I was determined to see if I could give it a final push to hit 270 species, and drew up an elaborate plan for new year’s eve. I was joined by the esteemed Albert Low, where we tried and failed to see the Pheasant-tailed Jacana at Marina East at dawn, before successfully seeing the skulking Lanceolated Warbler in the fields of Central Boulevard at mid-morning. The unforgiving north-east monsoon rain then came storming in, but we still managed to find the Plaintive Cuckoo at Jurong Lake Gardens by early noon. We then tried for the Orange-headed and Eyebrowed Thrush at Hindhede Nature Park, Greater Coucal at Bukit Brown, and the Phylloscopus warblers at MacRitchie, but the weather did not hold up. We were just out of luck, and were almost ready to give up at 6pm. Somehow, the skies cleared with the last hour of daylight remaining, and we decided on a last minute attempt to return to Bukit Brown for a second try for the Greater Coucal (also a bogey bird that I missed all year). Upon reaching the site at 6.55pm, there it was, atop a roadside tree, singing at the top of its lungs for a few seconds, before flying off into the distance. That was my 269th bird of the year, and a great end to my accidental sprint year (click here to see a breakdown of my list)!

Left: My 267th bird of the year, a skulking Lanceolated Warbler which appeared for a few seconds. Right: My 268th bird of the year, an adult Plaintive Cuckoo in the rain.

To be able to evaluate my report card of 269 bird species seen in a year, I was curious to know how many species were recorded by the whole of Singapore’s birding community in 2021 (or even other years for comparison). All I knew was that 2021 has been an exceptionally good year for birding in Singapore, with eleven new species being recorded for the first time. However, no such data was available, and so I took it upon myself to figure this out. With the help of eBird, I was able to find the records of every species. What made it even easier was Martin Kennewell’s immense effort to log every rare sighting that appeared on other social media platforms into eBird as well. Thank you Martin! The Singapore tally for the year was a total of 326 bird species recorded (see here for the complete list)! This meant that Jen Wei saw 89.6% of all bird species that were in Singapore this year with his record-breaking big year run of 292 species! Truly impressive (and superb)! A score of 269 meant I saw 82.5% of all species recorded, not too bad I think.

In most years, many of the rarer birds will appear in Singapore after September as the temperatures in the northern hemisphere begin to fall, triggering the start of the southward migration of many bird species to or through Singapore. This got me thinking as to how many bird species were recorded in the 8 months of January to August 2021 vis-a-vis September to December 2021 alone. What would the number of species I would have been able to see if I saw all of them since September, given my big year truly only started then? Can the next person give it a shot for a big year by having only to sprint for the last 4 months? Again, after dabbling with the data, the last 4 months of 2021 saw an impressive 303 species recorded, 18 more than the first 8 months combined! The numbers would possibly have been even higher if trips out to Singapore Straits to observe pelagic birds were not cancelled due to the Covid-19 restrictions.

Total number of bird species recorded in Singapore in 2021, and a breakdown of it from January to August and September to December. Birds featured in the illustration, clockwise from top left: Siberian House Martin, Cinereous Vulture, and Black Redstart. Reference images used for illustration by: Francis Yap

Blue: The total number of species that I saw at the end of each month in 2021. Dark grey area shows the progress from September to December when the sprint was on! Green: Total number of species that I saw at the end of each month counting only the birds I saw from September.

2021 has been an incredibly enjoyable year of birding for me, and I’d like to think that I’ve improved quite a bit and can now call myself a birder. I hope my journey and this article can inspire many others to start their own big year journey, even if it means not having a lot of birding experience or sprinting for just 4 months. Remember, a big year is not about the competition, but more about the challenge to better yourself!

Thank you to everyone who helped me along the way this year. They include my “well-intentioned” friends Albert Low, Dillen Ng, Bryan Lim, Sandra Chia, and Benjamin Lee, who have been patiently guiding, correcting my IDs, showing me spots, and supplying me with real-time updates of sightings and megas; the Singapore Birds Project team for running an excellent resource page and Facebook group and helping me with the birds in the field (Francis, Keita, etc.); birders who use eBird (thereby allowing me to closely follow the ‘recent visits’ and ‘rare bird alert’ pages) especially Martin, Jen Wei, Raghav, Subha and helping with the exact locations as well as in the field; and everyone in the community who were so willing to share bird sighting locations and spotting the birds (Oliver, Frank, Ramesh, Jacky, Alan, Movin, Kim Chuah, See Toh, Li Si, Clarice, Tuck Loong, Lester, Rovena, and many more that I’ve missed). 2021 was a great year that will be etched deeply in my memory, and it would have been nothing without the company and guidance along the way.

Rufous Barn Swallows in Singapore?

Science

TLDR;

There are several records of Barn Swallows with rufous underparts in Singapore
Relationships between the different Barn Swallow subspecies are still being explored – we are uncertain of which subspecies the rufous birds seen in Singapore belong to
In the meantime, please share your sightings if you come across any of these rarer migrants!

Migratory birds are slowly streaming into Singapore as the Northern Hemisphere winter sets in. One of the commonest species that share the local aerospace with the resident swiftlets and Pacific Swallows Hirundo tahitica is the Barn Swallow H. rustica. The Barn Swallows are easily identifiable from their distinct clean white underparts but did you know that rufous Barn Swallows have been seen in Singapore before?

There have so far been at least three documented records of Barn Swallows with rufous underparts in Singapore, one at Punggol Barat on 3 April 2016, one at Neo Tiew on 21 December 2019 and another at Neo Tiew on 20 January 2020 (though possibly the same individual spotted a month earlier).

The usual Barn Swallows that visit Singapore during the wintering months are of the subspecies gutturalis (Chasen, 1923; Gibson-Hill, 1950) with clean white underparts along with a distinct black breast band (Figure 1). It is currently still unclear which subspecies these rufous Barn Swallows belong to, but what the local community can do in the meantime is to make sure that these records are properly documented while researchers continue to study their relationships!

Figure 1. Barn Swallow, subspecies *gutturalis* (taken by Keita Sin).

This article will become slightly technical from here onwards, but for those who have an interest in the biology of birds, read on!

Barn Swallow subspecies taxonomy is tricky; different authors have differing opinions on which subspecies are valid and the boundaries of their breeding ranges (Figure 2, Table 1). With regards to the subspecies that occur in Southeast Asia (and consequently Singapore), the International Ornithological Committee (IOC) recognises four subspecies, namely gutturalis, tytleri, mandschurica and saturata, while Birds of the World (BOTW) recognises gutturalis, tytleri and mandschurica too, but treats saturata as part of gutturalis instead. On the other hand, Dor et al. (2010) who has worked on Barn Swallow phylogeny lists two relevant subspecies, gutturalis and tytleri.

Figure 2. Range map of the different Barn Swallow subspecies.
*Note.* Reprinted from The Barn Swallow (p 21), by A. Turner, 2006, A&C Black Publishers Ltd. Copyright 2006 by Angela Turner.

Table 1. A summary of the differing treatments of the Barn Swallow subspecies according to authors.

Of the supposed four subspecies that might occur in Singapore, only one is described to have creamy white underparts (gutturalis), with the other three (tytleri, mandschurica and saturata) have some degree of rufous on the underparts (Table 2).

Table 2. Morphometrics and plumage description of relevant Barn Swallow subspecies.
*Note.* Adapted from The Barn Swallow (p 20), by A. Turner, 2006, A&C Black Publishers Ltd. Copyright 2006 by Angela Turner.

However, on top of the difficulty in distinguishing underpart colours (what is the difference between ochre, rufous and chestnut?), plumage can also vary with individuals and wear (Dickinson and Dekker, 2001). More significantly, there is likely to be interbreeding between different subspecies in intergrade zones within their breeding range (Dickinson and Dekker, 2001; Nazarenko, 2016; Turner, 2006). For instance, there are some interesting swallows that are within range of tytleri and/or where tytleri overlaps with other populations (such as gutturalis) that are not entirely white or rufous, and some examples are listed here: a) western Mongolia, mostly white underparts with rufous tinge; b) central Mongolia, underparts with faint rufous tinge; c) central Mongolia, pale rufous underparts d) northern Mongolia, white underparts with rufous vent. Compare these with birds found further north (that are presumably tytleri based on range) such as this and this that are clearly much more rufous in colour.

As the ornithological community continues to explore the answers to the relationships of the various Asian populations of Barn Swallows in their breeding ranges, the verdict on the “rufous” individuals in Singapore is still open to interpretation. However this doesn’t change the fact that they are quite rare locally, so please do share your sightings if you manage to spot or photograph any!

Disclaimer: The authors of this short article (Dillen and Keita) have not been involved in any of the Barn Swallow studies. We dove into this topic confused and emerged out of it even more confused – please let us know if there are any errors!

References:

Chasen, F. N. (1923). An introduction to the birds of Singapore island. Singapore Naturalist, 2, 87-111.

Dickinson, E. C., & Dekker, R. W. R. J. (2001). Systematic notes on Asian birds. 13. Preliminary review of the Hirundinidae. Zoologische Verhandelingen, 25, 127-144.

Dor, R., Safran, R. J., Sheldon, F. H., Winkler, D. W., & Lovette, I. J. (2010). Phylogeny of the genus Hirundo and the Barn Swallow subspecies complex. Molecular Phylogenetics and Evolution, 56, 409-418.

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