On the morning of 15th February 2007 KC Tsang was at Changi documenting the food the male Oriental Pied Hornbill (Anthracoceros albirostris) was bringing to the female who was actively walling herself up inside the nest cavity. The bird brought the usual pieces of mud, insects and lizards for the busy female inside.

What puzzled KC was a non-food item the male brought in his bill. It was the upper part of an empty snail shell (left). The male displayed it to the female and then gently dropped it inside the cavity. Was it a gift of a ”toy” for his mate to play with?

This behaviour has been documented in Kg Gajah, Perak, Malaysia some years ago. As Dr Chan Kai Soon wrote, “…we noted the same thing (shells of snails) being delivered into the nest. We also thought that the male did this to provide calcium in the diet.” The shell piece was that of a land snail.

There is also an old report in the literature that the male Silvery-cheeked Hornbill (Bycanistes brevis) of Africa regularly brought inedible objects to the nest, like pieces of tree bark and sticks. Why? Probably as playthings.

It has now been established that calcium is an essential element in the diet of birds, especially those that do not obtain it from their primary diet. They thus seek out sources of this element during the egg laying and nesting periods. Various species of birds have been known to seek out calcium, the best example being the Scarlet (Ara macao) and Red-and-Green (Ara chloroptera) Macaws that take chunks of mineral-rich clay from steep river banks in Peru.

There are also published accounts of Black-capped Chickadee (Poecile atricapilla) eating ash that is high in calcium and Anna’s Hummingbird (Calypte anna) feeding on calcium-rich sand. And Arctic sandpipers use the teeth and bones of brown lemmings as a source of calcium.

The favourite food of hornbills is figs (above left). And figs are rich in water, carbohydrates and calcium. The presence of fig wasps inside the tiny fig flowers/fruits (above right) may provide added calcium. But I suppose, during breeding, the female needs more calcium than usual, thus the extra supply in the form of snail shells. And there are also the developing chicks to cater to.

Input by KC, YC and Dr Chan Kai Soon. Image of hornbill by KC and that of figs by YC.

Yen Lau has been twice lucky. She had two families of Oriental White-eyes (Zosterops palpebrosus) nesting in her potted Australian Bottlebrush trees (Callistemon rigidus) - the first family in sunny June and this second in wet Dec/Jan.

According to Yen: “This is what happened with my second white-eye family…

“On 16th Dec 2006 a pair of Oriental White-Eyes were seen inspecting my Australian Bottlebrush trees (left). Seven days later they started building their nest. White cobwebs were wrapped around slender branches about 2 metres or more from the ground. Eleven days later the nest was about ready when they incorporaterd grasses into the nest structure. This continued for the next two days. The nest was very thin but had a nice cup shape to it (below).

“As it was raining every day for the next one week, there were no activities. During a dry patch, one of the white-eyes appeared and sat in the nest. It stayed there all afternoon seemingly not doing anything. I didn’t look at the nest after about 6:30pm and it was still there then. On hindsight, it was probably laying eggs!

“As there had been a bird sitting in the nest constantly the last couple of days, I was sure eggs had been laid. I was skeptical of this at first because the nest was awfully thin. I peeked inside the nest. The bird very obligingly got up and perched on a nearby branch. I was greeted by the sight of 3 beautiful glossy white eggs measuring roughly 6mm X 15mm and snapped a few pictures (below left). The bird then casually hopped back into the nest again. Strange behaviour?

“The eggs could be seen through the thin nest (above right). Building materials were probably hard to find in the rainy season. (It poured heavily just about every day in December 2006 and the first week of January 2007.) The female was probably anxious to lay her eggs as well.

“Two of the three eggs hatched on 17th January (above).

“The parent birds took turns feeding the chicks. Unlike the parent birds in sunny June who appeared with food within 15mins each time to feed their ravenous young, these monsoon parents took as long as 25mins. These January chicks seemed more laid back too (above). They didn’t ever really stick their necks out and (quietly) scream like the June chicks did (left).

“By 23rd January the two chicks were starting to fill the nest and the nest was looking quite stretched (below). The chicks had grown more adult feathers. One looked more developed than the other. Two mornings later I found the remains of the unhatched egg. The birds had tossed it out. There didn’t seem to be much yolk and no white. The “yolk” I found was rather dense with one tiny but obvious dark spot in it.

“At around 1pm and exactly eight days after hatching, the bigger of the two chicks flew out of the nest (below). It did not get very far. First, it flew down to a shelf just a metre away. After some coaxing by the very excited parents, it flew back to the tree and stayed there for about half an hour. After that, accompanied by both parents, it flew off into the (nearly) blue yonder. (It didn’t pour that day – it drizzled on and off.)

“A few minutes after the first chick flew, the second chick followed suit. It flew an even shorter distance - barely a third of a metre away from the nest. It then fluttered around to various branches of the tree for the next half hour. (The parents were coaxing both chicks to fly in this frenzied half hour.)

“The parents came back after flying off with the first chick and continued to coax the second into flying off too. They brought bribes. I could see they had things in their beaks which they first showed to the baby before flying off a little distance.

“The second chick refused to budge. The parents gave up after a while and fed it.

“This chick seemed less developed than the June chicks when they started flying. Here’s a comparison… Our monsoon baby is the one on the left and a sunny June chick on the right (below).

“Here’s another picture of our second chick compared with a June chick (below). The feathers on our monsoon baby’s head aren’t anywhere near as developed as those of the June chicks’.

“Poor thing… The second chick was still there at 5:30pm, fluffed up against the wind and drizzle (below). It stayed in the same spot for the next six-and-a-half hours. All that time the parents continued feeding and coaxing it to fly. At one stage, I even saw one of the parents remove something white from its behind. Faecal sac?

“At 7:00pm this baby decided it was ready! It hopped up the highest branch and tried out its wings (below).

“Then, together with its proud parents, it flew off. Literally into the sunset!

“With the June family, I never saw or heard much from them after they left. With this family, I was still seeing them three days later. (If they are the same birds that is.) One of the birds I saw on 28th January was a young bird, probably one of the babies. (Something tells me it was actually the second chick but I can’t say why I thought that.) It had grown a tail but it’s still more rounded than an adult and slightly fluffy.

“It chirped very loudly and very insistently before flying off after its call was answered by an adult. Tut! Tut! Was it still calling for Mummy and Daddy?”

Input and images by Yen Lau; the above account obtained through the good-office of KC Tsang.

Baya Weavers (Ploceus philippinus) build their nests attached to branches of trees and shrubs and even fronds of palms. These nests are expertly weaved from long thin strands of leaf blades that can come from the Guinea grass (Panicum maximum) (left), strips of palm fronds or other tough fibres - see earlier post.

A completed nest looks like an upside down flask with a downward pointing entrance chute. Within the swollen portion is the nesting area.

If the female does not approve of the construction, he will abadon it. Obviously a strong and properly constructed nest is crucial to successful breeding as otherwise the nest may fall off before the chicks fledge.

The male bird usually builds the nest half way, up to the so-called helmet stage that consists of partly of the living chamber (right). He then tries to get his mate to be interested in the half-built nest. Once he has her approval, he will continue with the construction, completing it with a tube-like structure below the entrance.

The up to a metre long neck of the nest is tightly weaved around the support, in this case the thorny stem of a bushy sensitive plant (Mimosa sp.).

Found within the neck of the nest were a few fruits, probably those of the mason bee tree (Commersonia bartramia), a common weedy tree of abandoned areas (below). Why these fruits were placed there is anybody’s guess - probably to strengthen the neck area?

The closely weaved nest (below left) needs regular repairs, as with use and the extra weight of the chicks, the neck gets overly stretched. Repairs consist of weaving in new grass materials to tighten the nest and to secure its attachment. The presence of green strands in a mostly brown nest shows evidence of such repairs, rather than recycling of the nest. Lumps of clay have also been found plastered on the inner wall of the nest, probably to stabilise the nest (below right).

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Recycling is rare, if at all, as used nests harbour the complements of parasites that the weeks of incubation and brooding brings. The nesting materials will also have been weakened through slow rotting. Generally, used nests tend to elongate as the materials get stretched through wind and rain, to eventually fall off.

Old nests were provided by Tan Teo Seng.

Birds roost communally for a number of reasons. Coming together reduces their vulnerability to predators. And roosting in a central location allows for information exchange regarding feeding grounds. Roosting also enhanced protection from the weather.

Barn Swallow (Hirundo rustica) has a worldwide distribution, breeding throughout North America and from Europe eastwards to China. It migrates in large flocks southwards. The birds that we see in Singapore possibly come from eastern Asia (above). Many are juveniles, with a duller plumage and a less distinct breast band.

According to Chris Hails (Birds of Singapore, 1987, Times Editions), they can be seen in almost every month of the year but scarce in June. However, they are more numerous during August-April. In Peninsular Malaysia they can be seen in towns roosting on high tension wires.

Dr Wu Eu Heng and YC were at Yishin Street 71 in November 2005 to experience the roosting of masses of Barn Swallows on pulai trees (Alstonia spp.) along the road (above).

Individual birds grouped at pre-roosting sites nearby before moving on to roost communally. At around 6.30 pm the birds began to arrive (top). They could be seen flying from all around, to suddenly arrive amidst the flutter of wings and chirpings. They came in waves after waves, to land on the branches of the trees. Upon arrival there were much flying, chasing and vocalisation as individuals vied for choice roosting positions.

By 7.00 pm they had all settled down and quiet returned. It was quite an experience to be there, bringing back memories of Alfred Hitchcock’s 1963 movie, The Birds.

Early next morning the birds would prepare to fly off to their foraging grounds. This would involve another bout of squabbling before they fly off just after sunrise.

The noise they generated sent residents up the wall. Not to mention the droppings that they left behind. During bad weather the birds would congregate along the corridors to add on to the nuisance. Naturally there were numerous complaints and this resulted in the Town Council sending workers to trim the trees. This had limited effect on the roosting birds, but then there were other trees around for the birds to roost.

Over at nearby Chong Pang, the Purple-backed Starling (Sturnus sturninus) roosted in the sea apple trees (Syzygium grande) lining the road (above). As with the Barn Swallows, these starlings arrived after 6.30 pm in waves, gathering on certain trees before finally moving to the sea apple trees. Many of these trees were earlier trimmed to discourage the roosting of these starlings. So the birds moved on to those trees that were not trimmed. They obviously preferred full foliage trees for better protection from predators and the elements.

The Purple-backed Starlings were joined soon by Asian Glossy Starlings (Aplonis panayensis) and Javan Mynas (Acridotheres javanicus). The former gathered at roof tops while the latter in nearby trees before joining the waves of Purple-backed Starlings that moved on to their permanent roost (above).

Input by Dr Wu and YC, images by YC.

Our bird specialist R. Subaraj sent in this item after reading an earlier posting on Sentosa’s Buffy Fish Owl (above).

“Actually, while the Buffy Fish Owl (Ketupa ketupu) encounters are the first records for Sentosa and the Southern Islands, all the other four local resident owl species have been recorded for this island (below).

“Two species reside on Sentosa, with the Collared Scops Owl (Otus bakkamoena) being fairly common. The other resident, the Spotted Wood Owl (Strix seloputo), is rare with only one pair confirmed on the island.

“There are a couple of fairly recent records of the Barn Owl (Tyto alba) and it may still be resident. I have been told verbally that the species used to be commoner on Sentosa but most perished due to rat poisoning.

“The final species is the Brown Hawk Owl (Ninox scutulata). The resident sub-species, N.s.scutulata, is confined to and around the central nature reserves (Bukit Timah and Central Catchment) and Pulau Tekong Besar. Records from elsewhere in Singapore, including Sentosa, are of migrants from the north, probably of the subspecies N.s.japonica.

Regards, Subaraj”

Ilsa Sharp from Perth, Western Australia, adds: “I can confirm, as I’m sure Yeow Chin can too, that there were Barn Owls on Sentosa and that they died because of poisoning of the rats they ate - I remember well how we all #@*& the authorities for putting down the poison when they had been made well aware of the owls’ presence at the time! Must have been about early or mid-80s, do you think, Yeow Chin?”

Check out Owls in Singapore for a full list of species.

Input by R. Subaraj and Ilsa Sharp, image of owl by Chan Yoke Meng and of Sentosa by YC.