“It was an overcast and drizzly day and I decided to check up on some Glossy Swiftlets (Collocalia esculenta) that were nesting in an underground car park in the city. []

“While I was there I walked up the car park to the fifth floor as I saw Pacific Swallows (Hirundo tahitica javanica) flying and wanted an opportunity to take pictures in flight at ‘eye level’. I used the ‘sports’ function on the Nikon D90 camera to enable fast tracking, kept the zoom at 200mm and was handheld for flexibility.

“I followed as many birds as possible, pulling in the zoom once I got focus, and trying my ‘luck’ for some pictures. Many were blurred but got some interesting pictures in flight.

“While watching them for about 20 minutes I noticed five episodes of altercations. Three of the episodes captured were unfocused picture but managed two episodes with some clarity.

“Posted here are the two episodes: above: a composite of two birds in conflict (the third bird was not involved here) and below: two single pictures in sequence of another conflict (the third bird involved here).

“I was puzzled by the behavior. You can see that there was actual physical contact, although much of it was aerial pursuits and calls (‘shouting’). There were 6-7 Pacific Swallows at the site and I considered a number of possibilities for the behavior:

1. Firstly I considered mating conflicts as often it was two birds in conflict with a third watching.

2. Second possibility was territorial disputes but this is a high rise building, lots of space and did not seem likely.

3. Only after processing the images did the third possibility emerged – I think what is happening here is that juveniles (now immature adults) are still begging parents for food but parents have reached that stage where its time for the immature adults to forage on their own. I have seen this type of behavior often, especially with continual/daily observation in our garden, of a number of species. The immature/overgrown juveniles continue to harass parents for food even though they should be able to forage themselves. They chase parents from perch to perch, until finally parents reach a point and “retaliate”.

“If you look carefully at the composite (focus on bottom right frame first) you will notice that the bird in front has bold white ‘windows’ on the tail feathers at T2-6 (see Wells, 2007) that indicate it is an adult. But in the bird behind, these are hard to see and only appear as ‘pale dots’ indicating the bird is a juvenile (immature adult). Also notice the immature look at the mouth.

“In the second series (focus on Pacific Swallow-fight-3a) notice the adult on the left who was ‘supporting’, the juvenile in the middle and another adult on the right (shying away).

“Now the problem I am facing. Appreciate some opinion of my earlier post & this one.

“Notice these two pictures I have labeled one as adult in flight (below left)) and the other as immature in flight (below right). But even the one with bold white ‘windows’ on the tail feathers looks immature at the mouth. To compound the issue, I post a juvenile (Pacific Swallow-Juvenile on wire-6a), from an earlier trip, that has clear bold white ‘windows’ on the tail feathers (below).”

Dato’ Dr Amar-Singh HSS
Ipoh City, Perak, Malaysia
30th June 2010

Krys Kazmierczak responded to Amar’s problems: “I’m not sure about the difference in whiteness of the spots between adults and juveniles, but the visibility of the spots of course depends on how much the tail is spread. Since the spots are on the inner webs of the tail feathers T2 to T6, they are mostly covered by the (spotless) outer webs of the tail feathers which overlap them when viewed from above. Thus they only really stand out when the tail is completely spread. The spots are totally invisible, although present, when the tail is only partly spread and viewed from above (above right). If the tail is spread more than that, but not as much (above left), then the spots will simply appear smaller and duller, because they are partly covered by the outer webs of the tail feathers above them. I don’t know if that helps.”

Earlier, Hong & Cheng a.k.a. catspace posted an account of the Whiskered Treeswift (Hemiprocne comata) with images taken at the Johor’s Panti forest in Malaysia. The fragile nest was shown attached to a low, slender horizontal branch that was bare of leaves.

In early May 2010, Hong & Cheng returned from the same forest with much better images of the Whiskered Treeswift brooding a single chick. The delicate nest was about 5 metres up the tree, attached to a near-vertical slender branch, again leafless, with the half-saucer nest dangling from the side. The photographers initially saw the treeswift on the branch. When they noticed something moving around the feet of the bird they suddenly realised that there was a chick in the nest.

The blind and naked chick was covered with short white pin feathers that were beginning to sprout all over the its body. The adult was feeding the chick, which according to the photographers, was about thumb-sized.

Treeswifts build their nests with hardened saliva, reinforced with feathers. They are just big enough to accommodate a single egg, stuck to the nest with saliva. Otherwise the egg would probably roll off the nest. The incubating and brooding adult rests on the branch and not directly on the nest.

John Vickerman has this to say: “I am utterly astonished that the nest of this species appears to be so many times smaller than the adult bird. In addition, the nest looks to be so exposed to the elements and to predation, and it must use superglue to keep the whole affair fixed in place! Perhaps the minimal size and thus non-obviousness of the nest is a defence mechanism in its own right against predation. Whatever the evolution of this strategy may be, it clearly works! Lovely pictures and a delight to see.”

The nesting of the Grey-rumped Treeswift can be viewed HERE.

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

Whiskered Treeswift (Hemiprocne comata), unlike typical swifts, is able to perch firmly on twigs and branches with the aid of its non-reversible hind toe. It likes to sit in a rather upright posture at a spot where it has a good all-round view of the surroundings.

This image by Low Choon How a.k.a. dominator shows a Whiskered Treeswift perching on a branch and looking backwards. Yes, it has turned 180º which enables it to see at the back.

All birds have long necks. This is not apparent because the neck is folded in an S-shape and concealed by the feathers. The large number of cervical vertebrae that can rotate against one another in all directions allow for such movements. This ability compensates for the lack of eye movement in birds due to the large eyeball in a compact streamlined head that has no space for eye muscles.

An earlier post shows the Common Kingfisher (Alcedo atthis) making a similar 180º head turn, enabling it to preen its tail feathers while still perched on the branch.

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

“It has been a better migration year compared to last few years, with more Barn Swallows (Hirundo rustica gutturalis) and more first winter/juveniles seen. This group comprised approximately 150-160 birds, with 10-15% first winter/juveniles. They were preening mid-morning after feeding.

“Still a far cry from when I first came to this region (Perak) in the early 1980’s when we used to see thousands of these on electrical wires in Ipoh City. You had to be very careful where you parked when you went out at night to eat or else your car could get completely splattered by…

“The image at the top shows the swallows loading on a wire, sitting close to each other. That above shows a first winter/juvenile bird”

Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
15th November 2009

Choo Teik Ju’s studies of a Barn Swallow ( Hirundo rustica ) fledgling show the changing mood of the young bird as it waits for the adults to arrive with food. It sits quietly when the adults are not nowhere in sight (above left). Note the yellow flanges lining the mandibles. The moment it senses an adult coming, it gapes widely to highlight the yellow-red bottomless pit of a throat lined by the flanges (above right). At the same time screeching loudly. All these help guide the adult on where to deposit the food. Once the adult is in sight, the wings will unfold, probably to make itself conspicuous (below left).

Once fed, the fledgling may indulge in comfort behaviour, stretching its wings one at a time (above right) or both together and scratching its head.

The photographs were documented by Choo Teik Ju at the Mai Po Marshes, Hongkong.

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