In an earlier post on the Crested Goshawk (Accipiter trivirgatus peninsulae) (left), we provided an image of the raptor standing on one leg. This raised questions on why birds stand on one leg and whether it is a common practice.

“Why do birds stand on one leg?” has been a recurring question among birdwatchers for a very long time.

According to Evans & Heiser (2004), birds tuck one foot close to their bellies to keep warm on a chilly day. After all, the legs of most birds are not covered with feathers and they have been shown to be important sites of heat exchange (Steen & Steen, 1965). Other ways of conserving heat include tucking the bill into the feathers of the shoulder, fluffing their feathers to increase the air space and roosting close together.

However, the fact that birds also stand on one leg under warm conditions means that thermoregulation is not the only function.

And while standing on one leg, these birds continue to rest, preen or sleep.

Check out our earlier post on the Hooded Pitta (Pitta sordida) standing on one leg HERE.

References:
1. Evans, H. E. & J. B. Heiser, 2004. What’s inside: Anatomy and physiology. In: Podulka, S., R. W. Rohrbaugh Jr & R. Bonney (eds.), Handbook of bird biology. The Cornell Lab of Ornithology, Ithaca, NY. Pp. 4.1-4.162.
2. Steen I & J. B. Steen, 1965. The importance of the legs in the thermoregulation of birds. Acta physiol. scand. 63: 285-291.

Way back on 2nd September 2008, Dato’ Dr Amar-Singh HSS had an encounter with at least three Streaked Wren Babbler (Napothera brevicaudata leucosticte) (above left) feeding together with three or four Grey-Throated Babbler (Stachyris nigriceps davisoni) (above right). The location was half way up the peak of Gunung Brinchang in the Cameron Highlands, Malaysia – about 1800 m above sea level.

According to Wells (2007), the Streaked Wren Babbler is supposed to be loners or two or three in a family group. But here, they were part of a mixed foraging party of two species. And they moved together through the undergrowth for some time and occupied the same perches. This has not been reported by Wells (20070 who writes, “…with no definite record of hunting even in the base of understorey vegetation, although a bird in on Benom peak appeared to follow below a mixed foraging party moving through the understorey.”

A more recent encounter on 27th January 2010, along a trail at the edge of the Boh Tea Estate in the same Gunung Brinchang, this time at about 1,600m altitude provided Amar the opportunity to photograph the Streaked Wren Babbler (left). As Amar relates, “…came across a pair of Streaked Wren Babblers foraging in the open. They were about 1-1.15 meters from me in full view. We were equally surprised – the Streaked Wren Babblers and myself. One dived for cover but the other (?male) moved half a meter and then turned to have good looks at me. Despite my camera it continued to watch me and even offered many different “poses”. Was hesitant to take pictures at first in case I frightened it but it was so calm. The only problem with these pictures is that the bird was too close. At times the focus was only on one part of the body. Lots of pictures of a shy bird that we usually only get glimpses of. Was one of those magical moments with nature where we receive grace and all we have to do is open our hearts to let it in.”

Desmond Wong a.k.a. des95446 encountered a Malaysian Night Heron (Gorsachius melanolophus) in later December 2009. The bird was foraging, picking up some dead leaves then spitting them out. As it went about foraging, it suddenly stopped, raised its crest and lodged its lower mandible against the skin around the neck to widen its gape. It then shook its head left and right.

From the image below, there appears to be an elongated darkish foreign object stuck in the mouth. Was the heron trying hard to dislodge the object from its mouth? The attempt was unsuccessful and the heron continued foraging. Or was it casting a pellet? A dark elongated pellet?

Bird behaviourist John Vickerman has this to say: “…Clearly, there are two issues involved here: (a) regurgitation and (b) why is the lower mandible tucked into the fold of the neck skin?

“Regurgitation: As with nearly every bird species, herons do regurgitate pellets of unwanted or indigestible parts of consumed food. Casting of pellets is often accompanied by vigorous head shaking as witnessed by Desmond. In herons, (unlike with most raptors where bony material is nearly always cast via pellets), there are only very few instances where bony material of fish, amphibian or mammalian food have been found. Therefore, herons digestive processes seem to be able to cope very well with bones. However, herons do cast fur from mammals in pellet form.

“Now what is the material that is being attempted to be cast in Desmond’s image? Most bird pellets are, to a varying degree, elongated and oval in shape. It appears to me that this bird is attempting to cast a long and very thin object - rather ‘unoval’ in shape! I am uncertain that this is, in fact, a pellet in the process of being cast by regurgitation. If not, then what is it then? …might a long thin curled-up dead leaf have got stuck towards the back of the throat thus making it difficult to easily shake out with the rest? If that was the case, then it is not unreasonable to expect the bird to embark upon the more drastic, but quite normal, exercise of a regurgitation-type of retching exercise. …My belief is that either the item was discarded in one of the rapid head-shaking movements but out of sight of Desmond, or, with the discomfort at the back of the throat relieved, the item may have been swallowed in which case it could have been a food item that needed repositioning before being comfortably swallowed. I think we shall never know the answer for certain as to what the item was, or whether it was discarded or consumed.

“Lower mandible in the fold of the neck skin: In my opinion, this is the most fascinating part of what Desmond witnessed. …In Nature, there are occasions when something quite new is witnessed. One has to believe the evidence of one’s own eyes and new behavioural activities are being documented all the time. Desmond’s could be one such piece of observation documenting a new aspect of the behaviour of this particular and under-researched species as is noted in the book entitled The Herons (JA Kushlan & JA Hancock, Oxford University Press, 2005) that, ‘Much of the basic biology of this species remains to be determined. Information coming out of recent observations hints that this species may be of considerable biological interest. ….This is a species that could reveal new elements of Heron behaviour.’

“I can find no reference to this kind of behaviour in any of the literature I regularly use for reference purposes. …Certainly, Desmond’s evidence of this aspect of the Malaysian Night Heron’s behaviour is too interesting to hide away, especially since it seems there is very little known about many aspects of the biology of this species anyway. It would be a great reward if some researcher somewhere came out of the woodwork having noted similar behaviour, or someone who may wish to use this observation as a stimulus for a research study.”

As a postscript, John has this to add: “…birds can and do impale their bills accidentally in many different ways, and to reject the reasoning behind an observation outright concerning a piece of behaviour just because it hasn’t been recorded before is a very dangerous stance to take with sometimes embarrassing consequences! I learned many years ago that it doesn’t pay to suggest to people that they didn’t see or understand what they claimed to have seen and interpreted - Nature has a nasty habit of coming back and biting you and making you look utterly foolish! However, I do believe very strongly that Desmond’s account of his experience should be more widely circulated if possible, and certainly be archived for future reference. Further corroborative evidence of similar behaviour would be useful - not easy with a species like this which I believe is pretty skulking at best and invisible mostly! It is work like this that earns people their Ph.D.!”

Note: Through the courtesy of KC Tsang, Desmond’s images and observations were circulated in BirdForum. Although there were many responses on this weird behaviour, we have yet to receive any new information. We welcome any new imput.

This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.

Photographer Amit Thakurta documented a Brown Hawk Owl (Ninox scutulata) seizing the shuttlecock while he and his friends were playing badminton on the evening of 29th December 2009 in Jalpaiguri, West Bengal, India.

The images have been posted on the Bird Photography India and Delhibirdpix. Sumit K Sen of Kolkata posted the images in Birds of India and sent the link to KC Tsang after getting the permission of the photographer Amit Thakurta for BESG to repost them here. The account below is Amit’s story as told by Sumit.

“I would like to share an unusual experience with all of you. Some of my friends were playing badminton in a floodlit open court late in the evening. I was there and my camera was with me. Looking around, I saw a Brown Hawk Owl patiently watching the game from a nearby perch (above left).

“Suddenly, while the shuttlecock was in play, the bird made a sortie to catch the shuttle as if it was a prey species. However, it failed on this attempt and went back to the perch and continued observing the activity. This gave me the time to prepare my camera in anticipation of another try. And that attempt took place shortly afterward and the results are presented above.”

The top right image shows the owl seizing the shuttlecock; above left shows the owl flying off with the shuttlecock to its perch; and above right shows it manipulating the shuttlecock.

Terry Kaan came across a road kill while jogging down South Buona Vista Road on the morning of 15th November 2009. It was at the junction with Vigilante Drive that the Red-Legged Crake (Rallina fasciata) was found. He only had his iPhone with him at the time to record the event. “I live below Kent Ridge Park, and jog frequently there at all hours. But I have never seen a crake there,“ recounts Terry.

Ng Bee Choo adds, “…I believe the Red-legged Crake is quite common, often overlooked as they are shy. A long while ago it was found at the house Clive Briffett stayed while he was with the National University of Singapore, one of those black and white houses at Kent Ridge.”