RAP301: What is that raptor?

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.

FLY101: Identifying Little Brown Jobs of the genus Muscicapa in Singapore

Written by Clarice Yan and Zachary Chong

Worldwide, there are 26 extant flycatchers belonging to the genus Muscicapa. In Singapore, six species of the genus have been recorded here during the migratory season. Here, the Asian Brown Flycatcher M. dauurica is the most commonly sighted in relatively large numbers; Dark-Sided Flycatcher M. sibirica, Ferruginous Flycatcher M. ferruginea and Brown-streaked Flycatcher M. williamsoni are uncommon migrants occurring in smaller numbers. The Grey-streaked Flycatcher M. griseisticta is a very rare vagrant with the single record found at Sembawang this season. Lastly, the Spotted Flycatcher M. striata is also a vagrant with the single record this season at Kent Ridge Park.

Undoubtedly, these ‘brown jobs’ as they are affectionately termed are hard to differentiate. If we bump into them in the field, how do we know if we are looking at just another Asian Brown Flycatcher or the next mega sighting?

Ferruginous Flycatcher M. ferruginea

First, let’s look at the flycatcher most distinct from the rest – the Ferruginous Flycatcher. Often called “Iron Boy” by local photographers, this nickname is derived from its characteristic slaty-grey head combined with its orange-brown colouration and rusty-rufous fringes on its coverts and tertials. The rufescent rump, upper tail-coverts, tail and pink legs are also dead giveaways for the Ferruginous Flycatcher. In addition, the Ferruginous Flycatcher generally prefers dark, usually damp undergrowth in Singapore, unlike the other Muscicapa species mentioned, barring the occasional Dark-sided Flycatcher.

Key features of identification for a Ferruginous Flycatcher. Photo: Francis Yap. Infographic: Zachary Chong.

Spotted Flycatcher M. striata

One of the easiest features to pick out in the field for the Spotted Flycatcher is its thin, buff eye-ring as compared to the more white eye-ring in other flycatchers. The paler forehead, buff lores and distinctly streaked crown are also clear characteristics that separate the Spotted from other Muscicapa flycatchers. 

Key features of identification for a Spotted Flycatcher. Photo: Francis Yap. Infographic: Clarice Yan.

Asian Brown Flycatcher M. dauurica

The Asian Brown Flycatcher is an ashy-brown/grey-brown flycatcher with a bulky and strong-looking bill compared to other asian Muscicapa flycatchers. This species has broad white lores, and typically, a conspicuous and complete white eye-ring. The throat of this species is rather clean and the edge of its tertials are greyish-white. 

Key features of identification for a Asian Brown Flycatcher. Photo: Keita Sin. Infographic: Zachary Chong.

Brown-streaked Flycatcher M. williamsoni

In contrast to the Asian Brown Flycatcher, the Brown-streaked Flycatcher is warm-brown. This flycatcher also has less contrasting white lores, giving it a “plain-faced” appearance. Juveniles usually tend to have more defined brown streaks on the breast, upper belly and flanks (streaking may fade on adult Brown-streaked individuals). Its dusky throat, bulky bill with a more extensive yellow/orange bill base, and the occasional buffish eye-ring separate this species from the Asian Brown Flycatcher. The edges of the upper wing coverts of the Brown-Streaked Flycatcher are buffy. However, this trait is typically less distinct for adult individuals. Adult individuals tend to have less pronounced streaks on their breast and thinner fringes on their upperwing coverts.

Key features of identification for a Brown-streaked Flycatcher. Photo: Keita Sin. Infographic: Clarice Yan.
An adult Brown-streaked Flycatcher (left) which lacks streaking on the breast and flanks, which is similar to the Asian Brown Flycatcher (right). Photos: Keita Sin.

Dark-sided Flycatcher M. sibirica

The Dark-sided Flycatcher is cold grey and possesses a fine and small bill, which separates it from the other flycatchers. This species can have an incomplete eye-ring, which is more prominent at the back of the eye. The lores of the Dark-sided Flycatcher are also “dirtier”. The Dark-sided has a smudged greyish-brown breast and flanks, with heavy and dark streaking.

Key features of identification for a Dark-sided Flycatcher. Photo: Keita Sin. Infographic: Zachary Chong.

Grey-streaked Flycatcher M. griseisticta

The Grey-streaked Flycatcher is a cold grey coloured flycatcher, also possessing fine white lores and bill. Although similar to the Dark-sided Flycatcher, the Grey-streaked Flycatcher’s bill is longer than the Dark-sided, when viewed properly. This species can have a less conspicuous eye-ring. The Grey-streaked has defined, long pencil-like streaks on the breast and flanks, which differ greatly from the Dark-sided or Brown-streaked. The juvenile plumage for the Dark-sided and Grey-streaked Flycatchers are highly similar. In such cases, do consider the other traits listed above.

Key features of identification for a Grey-streaked Flycatcher. Photo: Francis Yap. Infographic: Clarice Yan.

Given that the aforementioned four Muscicapa species, namely the Asian Brown, Brown-streaked, Dark-sided and Grey-streaked flycatchers, are relatively more difficult to tell apart, here is a table for summary.

Trait ABFC BSFC DSFC GSFC
Plumage colour Brown Warmer brown than ABFC Cold grey Cold grey
Bill Bulky bill, orange on bill base Bulky bill, more extensive orange on bill base than ABFC Fine, short bill Fine, longer bill than DSFC
Eye-ring Conspicuous white eye-ring Occasionally buffish Less conspicuous white eye-ring, may appear incomplete in comparison to ABFC Less conspicuous white eye-ring, may appear incomplete in comparison to ABFC
Lores Broad and clean white lores Buffy, dirtier lores compared to ABFC Dirty lores Fine white lores
Chin White Dusky White White
Streaks on underparts Generally absent Heavy brown streaking on juveniles, less conspicuous and sometimes absent on adults Smudged flanks, sometimes smudged streaking on breast Fine, distinct streaks on breast and flanks
Edges to upper wing coverts Greyish-white Distinctly buffish Buffish-white Whitish

Further Traits:  Wing Length 

Wing length (and wing/tail ratio) increases from Asian Brown and Brown-streaked to Dark-sided and then Grey-streaked (Harris et al., 2014). This also leads to a progressively more pointed wing shape which can be observed; Asian Brown and Brown-streaked tend to have a more rounded wing shape and appearance.

Comparison of the wing lengths and wing to tail ratio of the Asian Brown Flycatcher, Brown-streaked Flycatcher, Dark-sided Flycatcher and Grey-streaked Flycatcher. Photos: Dillen Ng, Francis Yap, Keita Sin. Infographic: Clarice Yan.

One other Muscicapa possibility 

Now that we’ve covered the flycatchers that have been sighted in Singapore so far, we can turn our attention to a potential flycatcher that may someday make its way down south to Singapore. The Brown-breasted Flycatcher M. muttui is resident to India, China, Sri Lanka and is a visitor to Thailand, Tonkin, Myanmar, Laos (Robson, 2015). It is superficially similar to Asian Brown but is larger and has a broad whitish eye-ring, rufescent upperparts, greyish-brown crown and ear-coverts and warm greyish-brown breast/flanks. It could potentially show up in Singapore so keep a look out for this next possible mega!

Brown-breasted Flycatcher in Tamil Nadu, India. Photo: Raghav Narayanswamy.

We hope that this article helps in differentiating the many Little Brown Jobs you may encounter in the field in the coming months! Do keep a lookout for future articles about other Little Brown Jobs, and happy birding!

Acknowledgements

Thanks to the team for their thorough comments and help with this writeup, and also for providing the photos.

References

Harris, J. B. C., Rasmussen, P. C., Yong, D. L., Prawiradilaga, D. M., Putra, D. D., Round, P. D., & Rheindt, F. E. (2014). A New Species of Muscicapa Flycatcher from Sulawesi, Indonesia. PLOS ONE, 9(11), e112657. https://doi.org/10.1371/journal.pone.0112657

Leader, P. J. (2010). Brown, Siberian and Grey-streaked Flycatchers: Identification and ageing. British Birds, 14. Link: http://britishbirds.co.uk/wp-content/uploads/2014/05/V103_N11_P658%E2%80%93671_A.pdf

Robson, C. (2015). A Field Guide to the Birds of South-East Asia Second Edition. New Holland Publishers.

 

Further notes:

  1. Edited 16 January 2022: The comparison photo of the adult Brown-streaked Flycatcher and the Asian Brown Flycatcher was edited (adjustment of white balance) to better reflect the warm tones of the adult Brown-streaked Flycatcher individual.

RAP201: How to Identify Uncommon Raptors

Your handy raptor identification guide is back with a second installment – RAP201: How to Identify Uncommon Raptors! This article will cover seven species that migrate through Singapore in relatively low numbers: Grey-faced Buzzard (Butastur indicus), Common Buzzard (Buteo buteo), Eastern Buzzard (Buteo japonicus), Booted Eagle (Hieraaetus pennatus), Black Kite (Milvis migrans), Greater Spotted Eagle (Clanga clanga) and Besra (Accipiter virgatus).

Do check out RAP101: How to Identify Common Raptors to pick up tips on identifying common raptors and some background on raptor migration. As usual, we will be using the most mediocre of photos to show you do not need amazing gear for identification (though they undoubtedly come in handy for the trickier ones).

Grey-faced Buzzard (Butastur indicus)

Identifying features marked out on a Grey-faced Buzzard vs Oriental Honey Buzzard silhouette. Taken at St John’s Island, Singapore. Photo Credit: Sandra Chia

The Grey-faced Buzzard is a medium-sized migratory raptor. It has longer, slimmer wings than the Oriental Honey Buzzard (Pernis ptilorhynchus) when fully extended, with a white throat and dark mesial stripe. It also has five ‘fingers’ as opposed to the Oriental Honey Buzzard’s six ‘fingers’. In juveniles, that are similar in shape to adults, the mesial stripe are not as pronounced and they have streaks on their underparts instead of barrings.

Buzzards sp. (Buteo sp.)

Identifying features marked out on pictures of a Common Buzzard vs Eastern Buzzard vs Grey-faced Buzzard. Taken in Singapore. Photo Credit: Keita Sin

Buteo sp. refers to buzzards, that are stocky, medium-sized raptors with long wings ending in five ‘fingers’. They can be differentiated from Grey-faced Buzzards, which also have five ‘fingers’, by the lack of a mesial stripe, shorter tail, shorter and more rounded wings. Taxonomy of the Buzzards are contentious, with different ornithological authorities treating them differently – some consider the Common and Eastern Buzzards separate species while some recognize them as subspecies (Gill et al., 2021; Billerman et al., 2020; McClure et al., 2020). Common Buzzards (Buteo buteo) are browner overall compared to Eastern Buzzards (Buteo japonicus). Given the messy taxonomy it is currently unclear where exactly the Eastern Buzzards in Singapore arrive from.

Identifying features marked out on pictures of Booted Eagle vs Black Kite vs Oriental Honey Buzzard vs juvenile Brahminy Kite. Taken in Singapore. Photo Credit: Sandra Chia (Booted Eagle and Oriental Honey Buzzard), Keita Sin (Black Kite) and Yip Jen Wei (Brahminy Kite).

Booted Eagle (Hieraaetus pennatus)

The Booted Eagle has wings that are somewhat similar in shape to the locally common Brahminy Kites, with six ‘fingers’. It has pale shoulder spots on the upperwing, resembling ‘headlights’. Compared to the Oriental Honey Buzzard that also has six ‘fingers’, the Booted Eagle has a more compact, stockier giss and a squarish tail. The Booted Eagle can also be differentiated from juvenile Brahminy Kites and Black Kites by their lack of distinct ‘M’ shape in the wings and lack of white primary patches. This species has two morphs – dark and pale, and more information can be found on our species page.

Black Kite (Milvus migrans)

The Black Kite also has six ‘fingers’, but differs from the Brahminy Kite, Oriental Honey Buzzard and Booted Eagle by having a distinctly forked tail. It can also be told from Oriental Honey Buzzard and Booted Eagle by distinct ‘M’ shape in flight, resembling Brahminy Kites. However, the white wing patches in the Black Kite are restricted to the base of their primaries unlike juvenile Brahminy Kites that have a larger patch of white.

Greater Spotted Eagle (Clanga clanga)

Identifying features marked out on a Greater Spotted Eagle vs Changeable Hawk Eagle. Taken in Singapore. Photo Credit: Sandra Chia

The Greater Spotted Eagle has an overall dark plumage, with broad wings ending in seven ‘fingers’. It can be told apart from the Changeable Hawk Eagle by less rounded wings, resulting in less of an ‘armpit’ and the presence of a light vent. It is also much bigger. It also has white fringing on underwing coverts, with a whitish patch at base of outer primaries. More information on this can be found on our species page.

Besra (Accipiter virgatus)

Identifying features marked out on pictures of a Besra vs Japanese Sparrowhawk vs Shikra. Taken in Singapore. Photo Credit: Keita Sin (Besra and Shikra from Thailand) and Sandra Chia (Japanese Sparrowhawk).

The Besra is a sparrowhawk (typically referred to by their genus name Accipiter), and is hence small and closer in size to Japanese and Chinese Sparrowhawks. Like the Japanese Sparrowhawk and Shikra (also an accipiter – a very rare bird with only two local records), it has five ‘fingers’ but differs by having a strong mesial stripe, with its tail showing alternating dark and light tail bands of equal width. The Japanese Sparrowhawk in comparison typically has wider white bands, while the Shikra can be told apart by their much longer looking tail. The Besra has only been recorded in Singapore a handful of times, making it quite the rarity.

We hope this has been useful in telling these uncommon raptors apart. As some species can be rather tricky to identify, do check in with helpful birders on social media and identification forums when in doubt!

Not to worry, we have not forgotten about the Harriers. Keep your eyes peeled for the next installment, where we will dive into identification of Harrier species that migrate through Singapore!

Acknowledgements

Thanks to the field buddies, especially Max Khoo, Low Bing Wen and Oliver Tan, for suggesting a sequel covering uncommon raptors be done up and the team for their comments on the article.

References

Billerman, S. M., Keeney, B. K., Rodewald, P. G., & Schulenberg, T. S. (Eds.). (2020). Birds of the World. Ithaca, NY, USA: Cornell Laboratory of Ornithology.

DeCandido R., Nualsri C., Siponen, M., Sutasha, K., Pierce A., Murray, J. & Round, P. D. (2014). Flight identification and plumage descriptions of six Accipiter species on southbound migration at Khao Dinsor, Chumpon province, Thailand. BirdingASIA, 21(2014), 52-62. Link: https://www.researchgate.net/publication/303712756_Flight_identification_and_plumage_descriptions_of_six_Accipiter_species_on_southbound_migration_at_Khao_Dinsor_Chumphon_province_Thailand

del Hoyo, J., Collar, N., Marks, J. S. & Kirwan, G. M. (2020). Eastern Buzzard (Buteo japonicus), version 1.0. In del Hoyo, J., Elliott, A., Sargatal, J., Christie, D. A., & de Juana, E. (Eds). Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.combuz6.01

Eaton, J. A., Balen, B., Brickle, N. W. & Rheindt, F. E. (2021). Birds of the Indonesian archipelago, Greater Sundas and Wallacea. Lynx Editions.

Gill, F., Donsker, D., & Rasmussen, P. (Eds). (2021). IOC World Bird List (v11.2). Link: https://www.worldbirdnames.org/new/ 

Lindhom, A. & Forsten A. (2013). “Common”  Buzzards of South China and South-East Asia. Caluta, 4, 1-11. Link: http://www.caluta.liitin.net/Caluta/caluta4.html

McClure C. J. W., Lepage D., Dunn L., Anderson D. L., Schulwitz S. E., Camacho L., Robinson B. W., Les Christidis, Schulenberg T. S., Iliff M. J., Rasmussen P. C. & Johnson J. (2020). Towards reconciliation of the four world bird lists: hotspots of disagreement in taxonomy of raptors. Proc. R. Soc. B, 287. Link: https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2020.0683

Robson, C. (2008). A Field Guide to the Birds of South-East Asia. New Holland Publishers.

PIPIT101: Identifying Singapore’s First Tree Pipit Anthus trivialis

Written by Richard White, infographic by Keita Sin
Editing by Martin Kennewell, Keita Sin, Sandra Chia, & Dillen Ng

The birding community was presented with an identification challenge today with the arrival of a vagrant pipit species. These small, brown, streaky birds can be difficult to identify at the best of times. An unfamiliar, out of context, vagrant can be a real headache. So how to start the identification process? These notes might help.

Worldwide, there are about 40 species of pipit, mostly in the genus Anthus. Within Southeast Asia nine species are regular; in Singapore Paddyfield Pipit A. rufulus is a resident breeder, Red-throated Pipit A. cervinus is an annual non-breeding visitor in small numbers and Olive-backed Pipit A. hodgsoni is a rare vagrant with only one record at Bidadari in December 2010.

A bird discovered in a small suburban park in Clementi, Singapore, on 23 October 2021 by Soh Kok Choong was initially misidentified as a Eurasian Skylark Alauda arvensis. This species is a rare vagrant to Singapore with one previous record at Pandan Reservoir in November 2018. Jan Jaap Brinkman saw the post on 25 October, realized it was not a Eurasian Skylark but more likely to be a Tree Pipit A. trivialis (a first record for Singapore), and alerted the birding community. It was relocated quickly on 25 October and the identification of Tree Pipit confirmed.

But how do we know it is a Tree Pipit? Ideally, it would have been heard to call. While pipits tend to look alike (variations on brown and streaky), their calls are helpful and in most cases distinctive. Calls are notoriously hard to describe, which is why I am going to direct you to resources such as Xeno-canto should you wish to learn more about pipit calls. Unfortunately, this bird was either silent or could not be heard to call over the traffic on Clementi Road.

Faced with a silent pipit, how do we make an identification? First, let’s discount the commoner options (without spending time here on why it is not a Eurasian Skylark).

Of the three pipit species previously recorded in Singapore, Paddyfield Pipit is the commonest and therefore most likely pipit to be encountered. It is one of the larger pipits, >16 cm long and has a longer-legged and more upright appearance than the other pipits which are smaller and more horizontal in their stance. Size has to be used carefully, since the smaller pipit are merely < 16 cm long. Without being very familiar with pipits, this marginal size difference in a lone vagrant individual may not be helpful. The other feature that points away from Paddyfield Pipit is the extensive streaking across the breast of this bird, more than would be found on a Paddyfield Pipit. This combined with the short-legged, more horizontal gait, indicate that this pipit is not a Paddyfield.

Red-throated Pipit is the next most likely option. Smaller, with a more horizontal gait, this species is similar to a Tree Pipit in non-breeding plumage. However, the streaking on the breast typically extends strongly onto the flanks which this bird does not have. The upperparts are usually more boldly streaked to the rump as well, again lacking in this bird. Red-throated Pipit also typically has strong off-white mantle braces. These pale lines can be seen on this bird, but are not as well marked as would be expected on a Red-throated Pipit. The plumage tones of this bird give an impression of warm buff/browns in tone, while Red-throated Pipit should be colder grey/browns. So it appears the bird is not a Red-throated Pipit and therefore a real rarity.

Olive-backed Pipit is the only other pipit species to be recorded in Singapore. As the name suggests, the upperparts of this species should give an impression of olive/brown, which is not seen on this individual. Olive-backed Pipit typically also shows a strongly marked head and face pattern, with a clear supercilium above the eye and a well marked spot at the rear of the ear coverts. Lacking these features, this bird is not an Olive-backed Pipit either.

Now into the territory of a national first, the list of possibilities opens up. Within the region, Rosy Pipit A. roseatus would be more boldly marked, and Buff-bellied Pipit A. japonicus lacks the warm plumage tones of this bird. It is not one of the larger pipits (Richard’s A. richardii, Blyth’s A. blythi or Long-billed A. similis). We are left with Tree Pipit or maybe something even more extreme from outwith the region, such as a Pechora Pipit A. gustavi or Meadow Pipit A. pratensis.

Pechora Pipit is easily discounted since it shows a distinct primary projection beyond the longest tertial, which this bird does not show.

Meadow Pipit, typically a short distance migrant, is an outside chance from much further west. Though this makes it less expected, it should be considered. It is superfically very similar to Tree Pipit, but typically shows a clustered spot of streaking in the centre of the breast not shown by this bird. It is also less likely to perch in trees as this bird did often. The call is different but this silent bird does not help us. Finally and conclusively, scrutiny of digital images shows this bird has a short hind claw – shorter than would be seen on a Meadow Pipit.

Our lone, silent, pipit can be confidently identified as a Tree Pipit based on the plumage and structural features, as well as the behaviour and gait (jizz):

  1. Underparts: Well marked narrow black streaks across the chest/breast on a warm buff base. Streaks do not extend strongly onto the flanks
  2. Upperparts: warm buff/brown, with dark centred feathers giving a well marked, but not strongly contrasting, appearance. A well marked row of median primary coverts were slightly darker centred and paler fringed than surrounding feathers, producing a clear (but not bold) wing bar.
  3. General behaviour: spent most time walking through long grass foraging for invertebrates with a horizontal gait and occasionally giving gentle tail pumps (which is also a feature of Olive-backed Pipit). Flew with a strong bounding flight into mid-canopy of trees where it would perch, rest and preen before returning to feeding on the ground.
Key identification features of the Paddyfield, Red-throated, Olive-backed and Tree Pipit. Photo and infographic: Keita Sin
eBird screenshot of the Tree Pipit, taken 25 October 2021. It can be seen that this species is a long-distance migrant that winters in Africa and India.
eBird screenshot of the Meadow Pipit, taken 25 October 2021. This species is typically a short distance migrant, distributed further west than the Tree Pipit. It is therefore less expected for this species to arrive in Singapore.

Further notes:
1) Edited 26 October 2021: The upperparts description previously read “A well marked row of greater primary coverts … …”. This has been corrected to “row of median primary coverts … …”.
2) After the release of our article, Siti Soedarsono shared with us that she photographed the bird earlier at the same site on 19 October 2021. This date serves as the new first date for this record. We thank Siti for graciously sharing the information.

RAP101: How to Identify Common Raptors

The peak of Singapore’s raptor migration will soon be upon us. From October to December, large numbers of migratory raptors will pass through Singapore, as they move from their breeding grounds in temperate northeast Asia to tropical southeast Asia (Bildstein, 2006). This constitutes autumn migration, where birds migrate southwards to avoid frigid winters in their home grounds. Around March to May, the birds will head back north to breed, but fewer species seem to pass through Singapore and in smaller numbers. Different species of raptors have been observed to peak in their passage through Singapore in different months.

During this period, you’ll find birders heading to popular raptor watching spots such as Henderson Waves, Telok Blangah Hill Park and Tuas to try their luck at snagging rarer ticks, or to enjoy viewing the large number of raptors migrating overhead. At the same time, you’ll find posts popping up on local Facebook pages requesting for raptor identification. While raptor plates in field guides are handy for identification, good guides can be costly and those short on cash or new to the hobby may not be keen on making such purchases yet. Even so, while guides have detailed illustrations of the raptors in full colour with all identification features clearly indicated, migrating raptors often thermal high in the sky and our grainy, backlit pictures may look like this:

Large flock of migratory raptors at Henderson Waves, Singapore. Photo Credit: Sandra Chia

So how do we tell what’s what?

Equipped with my trusty but outdated Nikon 300mm F4 (no teleconverter!), my photos of migrating raptors may be the worst of the lot. Thankfully, you do not need amazing photos to identify the dots passing overhead. This article will feature five common raptors: Changeable Hawk Eagle (Nisaetus cirrhatus), Crested Honey Buzzard (Pernis ptilorhynchus), Chinese Sparrowhawk (Accipiter soloensis), Japanese Sparrowhawk (Accipiter gularis) and Black Baza (Aviceda leuphotes), and we’ll go through some general pointers on how to differentiate what’s what.

Changeable Hawk Eagle (Nisaetus cirrhatus)

Identifying features marked out on a Changeable Hawk Eagle silhouette. Taken at Henderson Waves, Singapore. Photo Credit: Sandra Chia

The Changeable Hawk Eagle is a medium sized raptor with seven ‘fingers’. Some individuals undergoing moult may have less than seven ‘fingers’, but can still be differentiated by its round wings, which result in a silhouette with pronounced ‘armpits’. This species can come in a dark or pale morph. This is an uncommon resident species that may often be seen while observing migratory raptors.

Crested Honey Buzzard (Pernis ptilorhynchus)

Identifying features marked out on a Crested Honey Buzzard silhouette. Taken at Henderson Waves, Singapore. Photo Credit: Sandra Chia

The Crested Honey Buzzard is another medium sized raptor with six ‘fingers’. The migratory subspecies, Pernis ptilorhynchus orientalis, is commonly referred to as Oriental Honey Buzzard. If moulting, individuals may also have fewer than six ‘fingers’. It can be differentiated from other medium sized raptors by its relatively small head and less rounded wings. The Crested Honey Buzzard also comes in various morphs such as light, dark, and an array of intermediate morphs (DeCandido et al., 2015). If you would like to take a deep dive into Crested Honey Buzzard identification, you can check out DeCandido et al. (2015).

Chinese Sparrowhawk (Accipiter soloensis)

Identifying features marked out on a Chinese Sparrowhawk silhouette. Taken at Henderson Waves, Singapore. Photo Credit: Sandra Chia

The Chinese Sparrowhawk is an Accipiter, a globally distributed genus typically known as hawks.  Accipiters are generally smaller than the two raptors discussed above, resulting in a very different general impression of their size and shape. This species has four ‘fingers’, tipped black. More information on how to identify males, females and juveniles of the species can be found on our species page here.

Japanese Sparrowhawk (Accipiter gularis)

Identifying features marked out on a Japanese Sparrowhawk silhouette. Taken at Henderson Waves, Singapore. Photo Credit: Sandra Chia

The Japanese Sparrowhawk is of similar size to the Chinese Sparrowhawk but can be told apart as it has five ‘fingers’ instead of four. More information on identification of males, females and juveniles can also be found on the species page, here. More information on telling apart Accipiter species can be found in DeCandido et al. (2014).

Black Baza (Aviceda leuphotes)

Identifying features marked out on a Black Baza silhouette. Taken at Henderson Waves, Singapore. Photo Credit: Sandra Chia

The Black Baza is of similar size to the sparrowhawks discussed above but differs by its wing shape, which is more rounded than that of the sparrowhawks, resembling paddles. It is also distinctly coloured, with a prominent band of white across the upper breast and thinner black, white, and chestnut stripes across the lower breast and belly. This species is mostly seen from late November onwards (eBird, n.d.).

We hope this article has served as a useful crash course on identification of common raptors we might encounter while raptoring in the coming months. Leave a comment below if you’d like us to cover other species!

Happy raptoring and hope to see everyone’s lists on eBird!

Acknowledgements

Thanks to Jin Rong and the team (Dillen, Francis, Keita, Movin and Raghav) for their comments on the article and to the experienced birders who taught me how to identify raptors over the years.

References

Bildstein, K. L. (2006). Migrating raptors of the world: their ecology & conservation. Cornell University Press.

DeCandido R., Nualsri C., Siponen, M., Sutasha, K., Pierce A., Murray, J. & Round, P. D. (2014). Flight identification and plumage descriptions of six Accipiter species on southbound migration at Khao Dinsor, Chumpon province, Thailand. BirdingASIA, 21(2014), 52-62. Link: https://www.researchgate.net/publication/303712756_Flight_identification_and_plumage_descriptions_of_six_Accipiter_species_on_southbound_migration_at_Khao_Dinsor_Chumphon_province_Thailand

DeCandido, R., Siponen, M., Smit, H., Pierce, A. & Allen, D. (2015). Flight identification and migration pattern of the Oriental Honey Buzzard Pernis ptilorhynchus orientalis in southern Thailand, 2007-2014. BirdingASIA, 23(2015), 27-33. Link: https://www.theflywayfoundation.or.th/download/Oriental%20Honey%20Buzzard%20in%20southern%20Thailand%202007%E2%80%932014.pdf

eBird. (n.d.). Black Baza. https://ebird.org/species/blabaz1/SG

Measurements of the 23 June 2021 Wedge-tailed Shearwater in Bishan

Pelagic birds are rather scarce in Singapore, so news of the grounded Shearwater found at Bishan-Ang Mo Kio Park on 23 June must have caught everybody by surprise. The bird was originally found by a passer-by below a HDB block in the area and then transported to the park. It was later spotted by William Khaw, who alerted the birdwatching community and ACRES. Many others contacted ACRES as well but despite being rescued, the bird did not survive. I was fortunate enough to take a look at the bird’s carcass with my colleagues and managed to get some measurements that are reproduced below. While photographs of the bird are aplenty online, I hope that these numbers will help serve as primary documentation for future birders as well as help those still wavering on the identification.

Feature Measurements of the Bishan bird (mm) Measurements (mm) of Wedge-tailed Shearwaters (WT) and Short-tailed Shearwaters (ST)
Tail 119.0 WT: 123-138
ST: 78-85
(Pettit et al., 1984; Longmore, 1985; Wells, 1999).
Bill depth at base 11.3  –
Bill depth at nare (tip of the nostril) 10.2  –
Minimum bill depth 7.4  –
Bill to skull 46.5  –
Bill to feathers 39.0 WT: 38.47±1.89
ST: 31.82±1.37
(Bull et al., 2005)
Head plus bill 81.8  –
Wing 279.0 WT: 292.99±9.99
ST: 267.11±13.06
(Bull et al., 2005)
Tarsus 47.3  –
Mid-toe (including claw) 58.5  –
Mid-toe (without claw) 50.7  –

The Wedge-tailed Shearwater Ardenna pacifica can be distinguished from the more locally expected (though still rare) Short-tailed Shearwater A. tenuirostris from a number of features. These include the bill shape (comparatively long bill to head ratio) and the tail extension (long in Wedge-tailed Shearwater, shorter in Short-tailed Shearwater). For those who are less familiar, comparison of the measurements against other sources unequivocally confirm the identification as a Wedge-tailed Shearwater; the similar looking Short-tailed Shearwater measures much smaller.

Of the three species of Shearwaters that have been recorded regionally so far, the Short-tailed Shearwater is the most expected around the nation. Although a rare bird locally, it has been reported semi-regularly in recent years along the Singapore Straits during pelagic trips (https://ebird.org/species/shtshe). Instead, there is only one record of the Wedge-tailed Shearwater so far, yet another grounded bird that was photographed at Woodlands on 22 June 1998 (Wang & Hails, 2007). Coincidentally just 1 day apart, although 23 years ago! The third species, Streaked Shearwater Calonectris leucomelas is expected, though no verifiable records are present as of yet.

If you find any wild animal that needs help, please contact ACRES at 97837782 and/or the NParks hotline at 18004761600.

Acknowledgements

Massive thanks to the staffs at ACRES, especially Kalai and Ava, who helped keep and pass the carcass to the NUS Avian Evolution Lab, to all who assisted in the rescue process, and to William Khaw for sharing the sighting with the community. I would also like to express my gratitude to Art Toh, Dillen Ng, Martin Kennewell, Movin Nyanasengeran and Tan Hui Zhen for the help in preparing this short piece.

Literature cited

Bull, L. S., Bell, B. D., & Pledger, S. (2005). Patterns of size variation in the shearwater genus Puffinus. Marine Ornithology, 33, 27-39. Link: http://www.marineornithology.org/PDF/33_1/33_1_27-39.pdf

Longmore, N. W. (1985). Two new records of the short-tailed shearwater from north Queensland. Sunbird: The Journal of the Queensland Ornithological Society, 15(4), 84. Link: https://birdsqueensland.org.au/sunbird_issues/Sunbird_Vol15_No4.pdf

Pettit, T. N., Byrd, G. V., Whittow, G. C., & Seki, M. P. (1984). Growth of the Wedge-tailed Shearwater in the Hawaiian Islands. The Auk, 101(1), 103-109. Link: https://sora.unm.edu/sites/default/files/journals/auk/v101n01/p0103-p0109.pdf

Wang, L. K., & Hails, C. J. (2007). An annotated checklist of the birds of Singapore. Raffles Bulletin of Zoology, 15, 1-179. Link: https://lkcnhm.nus.edu.sg/wp-content/uploads/sites/10/app/uploads/2017/04/s15rbz001-179.pdf

Wells, D. R. (1999). The birds of the Thai-Malay peninsula (Vol. 1). London: Academic Press.