The Changeable Hawk Eagle (Spizaetus cirrhatus) found in this part of the world is the subspecies limnaeetus. It is crestless and is found from the Himalayan foothills down through Southeast Asia into Greater Sundas to Philippines. This subspecies is polymorphic, with a dark and a pale morph (above).

The sexes are similar but the female is slightly larger. The juvenile (pale morph) is distinct, with its head and underparts largely white (left). Juveniles begin to breed in the third year and become fully adult in fourth year or later.

The adult pale morph is brown above, with pale edges, especially on wing coverts. The pale brown tail has a thin whitish tip, broad blackish subterminal band and three to four other narrower, browner and often much more obscure bars. The white to buff area of the throat to breast and upper belly and flanks are more or less boldly streaked with black to dark brown.

The adult dark morph is entirely blackish-brown, including the uppertail, the inner half being greyer.

The wings are shortish, with the wing tips about one-third to half down tail; tail long and thinly-banded.

Legs are long, feathered; appearing spindly because of the short tibial feathering.

The bird perches upright, especially in the early morning and afternoon. It stays for long periods waiting patiently for prey. These may include squirrels, birds, snakes and lizards.

During mornings, the eagle soars alone or in pairs, taking advantage of the thermals.

Images by Mark Chua except the dark morph eagle by Chan Yoke Meng.

The earlier post on the crocodile sighting at the Sungei Buloh Wetland Reserve (above) has attracted another comment from R. Subaraj, a nature consultant and bird specialist:

“Actually, from what I hear (and this needs confirmation from NParks), the croc in question just got too comfortable in its surroundings and started taking up residence in the visitor centre ponds. This is an active public zone, with lots of school kids and families at certain times and as such, the level of danger increased. As a result, the difficult decision was made to remove the crocodile altogether. At the end of the day, when public safety was compromised to such a point, NParks had to act to maintain the balance between nature conservation and public safety, I guess.

“The crocodile farm staff, who have experience in crocodile capture, were called in and the croc was caught and taken to the farm. The croc farm people were only too happy to agree as a wild caught male is difficult to come by and is ideal for breeding purposes.

“Why was the zoo not called upon? I do not know except that they may not have wanted the croc as they have enough. They often turn down many animals as they do not have the space or take them and re-release them into the central reserves (pangolins, pythons, etc.).

“Why was the croc not removed to another part of the wetlands reserve? Well, considering the relative small size of the reserve, it would probably have found it’s way back or continued to be a problem where it was as it had become too ‘tame’.

“There are several problems with the way the public and nature circles view conservation in Singapore. We cannot compare our reserves or circumstances with other countries, where their protected areas are substantially larger or their populations not so crowded into small spaces. Managing reserves here and conserving our natural treasures have to be done so in a somewhat unique fashion as the public impact is far greater for the reasons above. I do not envy NParks responsibilities and the pressures that they face. They could use all the support and advise that they can get but it should be done without undue criticism and fault-finding…..as has been the case in the press often.

“I do not speak for NParks and it may still be worthwhile seeking their views. These are merely my views based on what I have heard and seen.”

Image of reserve by YC and that of the croc by KC Tsang (who had another close encounter on 25th July 2007).

“What caused two nesting failures on the same plant?” was posted earlier. Lam Chun See then thought that the pair of Olive-backed Sunbirds (Cinnyris jugularis) that had been busy constructing their nest attached to his bromeliad plant abandoned it after completion. He realised this was not so when, on 16th July 2007, he found out that the female had discreetly returned regularly, to lay her eggs and to incubate them.

On 27th July his children reported that the eggs had hatched and there were two chicks in the nest (top left). By 4th August the chicks were very active, calling for food whenever any of the adults were around (top right). The images below show the male (below left) as well as the female (below right) helping to feed the hungry chicks. Note the extremely wide gape of the hungry chicks as they eagerly waited to be fed.

As Chun See wrote in his blog: “I noticed an interesting behaviour. After they have found some food, they would not fly directly to the nest. Maybe, they spotted me lurking behind the curtains with my camera. So what they did was to first fly to a nearby branch and check out the situation for about 10 to 20 seconds. When they were sure that the coast was clear, then they would fly to the nest to feed the babies.”

As with many birds, soon after feeding the adult will remove the chick’s wastes which are excreted enclosed inside a neat mucilaginous faecal sac. This is picked up from the chick’s posterior end and deposited some distance away from the nest. Why? You need to check out (1, 2) to find out. In the images above, the one on the left shows the female adult poking her head into the nest chamber to remove the faecal sac, shown on the right.

On 11th August the older chick fledged, flying into the neighbour’s house. The parents were around making lots of noise. When Chun See checked on the nest, he found the other chick inside. But his presence caused the second chick to also fledge. So the nest is now empty.

Once upon a time, a pair of binoculars was absolutely essential if you want to go bird watching. A good pair would enable you to view the plumage and identify the bird. With the advent of digiscopes, birders could see further than the average pair of binoculars. And if you attach a digital camera to the digiscope, you may be able to take a clear shot of the distant bird – provided the bird is cooperative and does not move about.

Then came digital photography. And this changed the birdwatching scene completely. Now you need not go watching birds with a pair of binoculars. A digital SLR camera attached to a 300 mm lens and a 1.4 teleconverter can take the place of the binoculars. The added advantage is that you can now also have an image (or many, many images) with a click of the shutter.

So, if you want to study birds, a digital camera with the necessary attachments can be invaluable.

Many details are not seen when birds are viewed with a pair of binoculars – the action may be too swift or the details too small to be noticed on the spot. A crisp image can always be examined on the computer screen, and enlarged if necessary, in the comfort of your home. Details will then emerge that are not noticed in the field.

Since its formation, the Bird Ecology Study Group has been working closely with photographers, accumulating a mass of behavioural traits on our local birds. We have been able to identify the food birds take to the generic or even to the specific level (1, 2, 3, 4). The details of the eyes, tomial teeth, feathers, etc. can now be closely examined and compared. Rapid movements in flight, courtship rituals and a host of other behaviour can be analysed at leisure once images are available.

All these are highlighted in the recent article published in No. 46, Issue 7/2007 of Asian Geographic (above). The original title “Birders, photographers and the study of bird behaviour” has been editorially changed to “Bird Watch: A field guide to the passion for birdwatching in Southeast Asia”. This piece is a collaborative effort by a field photographer, an experienced birder-cum-photographer and a naturalist who is an accidental birdwatcher.

Check out the article in the latest issue of Asian Geographic to find out how photographers have been contributing enormously to the knowledge of bird behaviour during the last two years.

Now, if you want to study birds, lug a digital camera with you. You can always leave your binoculars behind.

Yes, what does a tailorbird do at night? Or all diurnal birds for that matter. Why, some but not all sleep. Many waders feed at night when the mudflats are exposed due to low tide. So they cannot afford to sleep. Other birds feed at night because it is safer to do so when many predators are asleep.

Many birds sleep with the head turned and resting on the shoulder and the bill tucked among fluffed up plumage of the back. They may sleep standing up of sitting with the feet locked on the perch. Some sleep clinging to tree trunks with their toe nails eg. treecreeper.

Where birds sleep is important.

Some species come together in communal roosts to sleep, either the year round or only during the non-breeding season. Snuggling together helps to significantly reduce heat loss. Hole nesters roost inside their cavities. Other birds sleep in groups or alone. They usually sleep under cover of vegetation.

But this apparently was not so with the tailorbird.

In April 2007, Ng Bee Choo and Morten Strange were holidaying in Taman Negara, Malaysia. On their way to dinner one night, they stumbled on a small ball of feathers attached to the leaflets of a palm sapling. On recognising that it was a sleeping bird, Bee Choo rushed back to her room to get a camera. Not wanting to disturb the sleeping bird, she did not switch on the flash.

Her image of the sleeping tailorbird is shown above. It shows a smallish ball of feathers, the two feet locked on the base of the palm leaflet. The head of the bird was tightly tugged under a wing such that the bill was totally out of sight. The feathers were fluffed. These are the ways birds keep warm.

At one end of the ball of feathers was a small, narrow tail, distinctly obvious. The rufous crown and one of the black shoulders can be distinguished.