Thursday, October 24, 2013

Bornean and White-crowned Forktail

It has long been established that there are two races of White-crowned Forktail Enicurus leschenaulti in Borneo, one from highland E. l. borneensis and the other E. l. frontalis from lowland, but there are occasional records of overlaps while the highland form is found in lowland and vice versa.

Moyle et. al. (2005) demonstrated these two forms are different phylogenetically and morphologically and the montane form is a different species endemic to Borneo.

Mann (2008) in his Checklist for Borneo classified the lowland form as Southern White-crowned Forktail E. l. frontalis and the the highland form as Northern White-crowned Forktail E. sinensis borneensis

Sheldon et. al.  suggested in 2009 that the highland form to be called Bornean Forktail Enicurus borneensis here.

These two forktails sound and look identical, birders traditionally distinguish them by habitats. Their specimens collected from Borneo are distinguished by measurements, however, their wing and tail lengths overlap and are confusing.  Identification based on observation of tail length is not reliable as it varies among different individuals and may be age related.

Susan Myers (2009) is the first to suggest that Bornean Forktail has lesser white in its forehead than the lowland White-crowned Forktail in her Field guides to the Birds of Borneo.

I have wanted for quite some time to prove her point, but good photos of  White-crowned Forktail are hard to take, they are skittish and usually occur in remote forest streams. Bornean Forktail, on the other hand, is relatively easier to photograph in Kinabalu Park, so we have good photos of Bornean Forktail in the Internet while photos of White-crowned Forktail from Borneo are hard to come by.

I have over time accumulated photos of White-crowned Forktail from Borneo, these photos are from Tawau and Tabin, far away from high mountain ranges of Borneo, so it is quite safe to label them as such.

The following composite images show the forehead and front of individual birds, after looking at them and other images in the links, we know we can reliably use the extent of white in the bird's forehead to positively ID the bird, especially in areas where they overlap.

 Birds with crown feather lifted (left panel : Bornean Forktail from Kinabalu Park, right panel : White-crowned Forktail from Tawau (upper bird from Andrassy Forest Reserve, lower bird from Tawau Hills Park.)

Birds with crown feather at rest. (left panel : Bornean Forktail from Kinabalu Park, right panel : White-crowned Forktail (upper bird from Andrassy Forest Reserve, Tawau, lower bird from Tabin Wildlife Reserve)

It is evident from above that the extent of white in the forehead and crown of these two species differ, especially visible when the crown feathers are lifted. When at rest the forehead white feather of White-crown Forktail extends well towards the crown touching the upper nape, while Bornean Forktail only has the white forehead feather extends midway to the crown.

More images of Bornean Forktails are here:

More images of White-crowned Forktail from Danum Valley, Sabah, Borneo are here:

Happy birding.

Photodocument of the wild birds of Borneo.

Standard references for my blog.

Tuesday, October 8, 2013

Mulu Short-tailed Babbler ?

There is a mysterious Short-tailed Babbler, (similar to the Short-tailed Babbler Malacocincla malaccensis poliogenys of Sabah, Brunei and eastern Borneo, and the Barito drainage in Southern Kalimantan, and M. m. saturatum of western Borneo) dwelling in the forests of Borneo, it was not seen nor photographed in the wild since 1898.

Its existence is without doubt due to a specimen taken from Gunung Mulu in Sarawak in 1898.

The following passage is copied from Smythies, The Birds of Borneo, 4th Edition.

"Another taxon, M. m. feriatum Chasen & Kloss 1931,was described from a single specimen collected by J. Waterstradt in March 1898, from an unrecorded altitude at G. Mulu. This may represent a distinct species (Deignan, in litt. to Smythies), with an entirely ochraceous underparts from the chin and throat to vent (except central abdomen) and chestnut crown contrasting with the mantle, the mantle lacking the greyish tinge obvious in Sabah examples of M. m. poliogenys. Wing 75, tarsus 30, bill from gape 23.5 mm. All other races have the throat white. This form could be montane, but no evidence of it was reported from the Royal Geographic Society expedition to G. Mulu National Park in 1977-78."

Apparently no one has seen or reported it since than.

Its only illustration can be found in both first and second edition of Phillipps' Field Guide To The Birds Of Borneo, in which the bird is depicted just like what is described in Smythies. For obvious reason, Quentin has named it Mulu Short-tailed Babbler, (For ease of narration, I will call it Mulu Short-tailed Babbler or Mulu Bird here), he also thinks it probably occurs in  montane forests, in contrast to Short-taild Babbler which occurs elsewhere in lowlands in the same National Park

I have on 14th September 2013, photographed a bird which looks remarkably similar to the Quentin's Mulu Bird in Tawau Hills Park, the image is shown here with other images of Short-tailed Babbler for comparison.

This is the Tawau Hills Park Bird.
Same bird showing a little more throat and breast.
Close up of the head showing the lack of white throat
This is a Short-tailed Babbler of the poliogenys race about 100 meters away from the earlier bird, but taken one week later, for comparison.

This is a Short-tailed Babbler photographed in RDC, Sepilok, Sandakan Sabah, also of the poliogenys race.

The Tawau Hills Park bird is photographed in lowland habitat similar to those inhabited by Short-tailed Babbler. This shows that these two birds are sharing same habitat, therefore, could this two birds are actually different taxon? Well, may be,  our different Bulbuls are sharing common habitats, feeding on the same fruits from the same trees in the same forest.

Could this be a bird in juvenile plumage? The bird in the image does not look like a juvenile bird as the light color gape line is no more visible, indicating that it is a mature bird. An image of juvenile Short-tailed Babbler taken nearby in Tawau Hills Park show whitish throat, however, there are some young individuals showing varying amount of ochraceous on the throat, but the white on the throat is usually prominent.
Image of juvenile Short-tailed Babbler, courtesy of my Bird photography buddy My CP Lim, taken in Tawau Hills Park, showing contrasty white throat.

The original Mulu bird is popularly perceived to be of montane origin, but no altitude data was recorded for that specimen. However, some birds in Borneo are known to occur in a wide altitude range, occuring both in montane and lowlands habitats. Velvet-fronted Nuthatch Sitta frontalis, Little Cuckoo Dove Macropygia ruficeps and Checker-throated Woodpecker Picus mentalis, to name a few, are all  found both in lowland and montane forests in Borneo. So the Mulu Bird could possibly be lowland, montane or both.

Am I saying that this is the Mulu Short-tailed Babbler? I do not know, although this individual looks very different from the Short-tailed Babblers that we normally encounter, there are so many unknowns for the Mulu Bird, we need more info to be sure.

I have discussed this with Mr Quentin Phillipps who has shared his view with me and I take the liberty to share his thoughts on this bird here.

"Given the fact that it was found in the lowland forest where there are already many Short-tailed Babblers my guess is that it is an age related variant of the normal Short–Tailed Babbler eg immature first year bird or something similar  but there is a possibility that it could be a cryptic species. This can only be proven conclusively if you find several similar birds living in the same area and if the breeding song is distinctively different from that of Short-Tailed Babbler. Obviously it is well worth further research to find out what the situation is." 

Hence, this entry in my blog is to alert birders and photographers out there in Borneo not to ignore the lowly Short-tailed Babbler they encounter in the field (my mistake of taking for granted this is another ordinary Short-tailed Babbler, otherwise I would have taken many more photographs from this encounter), the ochraceous  throat may not be readily visible under dim forest light and in thick undergrowth where this species love to forage, its habit of incessant hopping about is not helpful for birders and photographer to make a clear and unobstructed observation either.

With additional input, we would than know whether there is actually a Mulu Short-tailed Babbler M. m. fetiatum or the Mulu bird is just a variant of Short-tailed Babbler.

Before I conclude, let me share an interesting image of a Short-tailed Babbler from sifu Sulaiman Salikan taken in Taman Negara, Sg Relau, Merapoh, Pahang on 5th October 2013. This bird is of the nominate race M. m. malaccensis, we can see that its throat is not as contrastingly white as we usually see, which indicates there are varying amount of ochraceous present at the throat of different individuals.
Short-tailed Babbler M. m. malaccensis Taman Negara, Pahang

Happy birding.

Photodocument of the wild birds of Borneo.

Standard references for my blog.

Sunday, October 6, 2013

Rare and notable bird sightings in Sabah - 2nd & 3rd Quarters 2013

The list shows the notable bird sightings in Sabah in the second and third quarters of 2013, feel free to email me if I miss out anything.

A Word file with links to the relevant images is at Borneo Bird Images Document list.

Happy birding.

Photodocument of Wild Birds of Borneo.

Standard References for my blog.