The three eggs in the crows’ nest as seen in Tang’s earlier image, also shown here, show similarity in colour and pattern. However, one of the eggs is of slightly different shape than the other two and smaller. And according to the literature, the Asian Koel’s (Eudynamys scolopacea) egg is smaller than that of the House Crow’s (Corvus splendens). Can the smaller egg then be that of the koel’s? We need to monitor the situation and wait for the hatching. The nestling of the koel can easily be differentiated from that of the crow once feathers develop (see image of koel nestling, bottomj).

Angie found bluish shells with dark speckles as well as light cream ones at the base of the tree where the crows’ nest was the day after koels attacked the nest (see image on left as well as earlier posting. Is it possible that either the crow or the koel laid eggs of two different colours? After all, as Lin Yang Chen pointed out, there are reports of egg dimorphism among certain species of birds. Unfortunately bird watchers have yet to pay much attention to such details.

Input by Hung Bun Tang, Angie Ng and Lin Yang Chen
Images (top to bottom) by HBT, Angie and YC

After last night’s series of attacks by the Asian Koels (Eudynamys scolopacea) (see 2; also 1), I went downstairs this morning to survey the grounds below the tree well before the sweepers arrived. There were egg shells lying around, bluish shells with dark speckles, probably those of the crow’s.

The light cream shell with faint brown specks, seen on the lower portion of the image, was picked up yesterday around noon. I wonder whose egg was this? Could it belonged to the koel that made the dramatic attacks, missing the nest when she dropped an egg?

This morning there was always one House Crows (Corvus splendens) staying put in the nest all the time. It sat with its beak apart, shifting her position several times. It must be tedious sitting there under the hot sun! As far as I can ascertain, it only took a short break of about four seconds, leaving the nest and remaining just outside the nest, stretching itself.

At 1.00 pm its mate flew in to check on the situation, flying off almost immediately after. But a minute later it returned with some food (cannot see what it was) that it inserted into the nesting bird’s mouth. Wow! I presume that was the male bringing food to the incubating female.

Quick as a wink the arriving bird took off again, to return twice. I am not able to say whether there were any exchange of food as my view was blocked by the large nest.

I was out till late tonight, and it was raining. Was there another assault?

Now at 10.10 pm, sitting at my computer, suddenly a crow cawed twice. I looked out just in time to see the foliage ruffled and a koel crying ‘kweek kweek’ as it fluttered downwards out of sight. Two minutes later a koel in the tree called ‘kweek kweek…’. Was the Koel still in the tree? Did it drop in another egg? At 10.20 pm crow cawed again, but I did not notice any disturbance around.

The koels here seem to strike at night.

Contributed by Angie Ng, 27th December 2005; image also by Angie.

According to Laurence Kilham’s “On watching Birds” he says “almost nothing was known of life of American Crow in spite of its being among the commonest of birds.” More so in Singapore, the House Crow (Corvus splendens) is considered to be a pest and a threat to all native birds. It is regarded as public enemy number one and bounty hunters are paid according to the number of birds they shoot.

I usually would walk past a yellow flame tree (Peltophorum pterocarpum) at the corner of a car park as I entered the back of my clinic. It was on March 9, 2005 that I first noticed the presence of a nest in the canopy of the tree. How long it took to build the nest I am not sure, but it must have been quite fast, as I did not notice it before. The nest was seated on the forks of a tree branch and shaped like a bowl surrounded by twigs arranged in a circular fashion about 10 meters from the ground. My observations were made from the ground and from the landings of an adjacent Housing and Development Block. As I was not able to look into the hollow of the nest, I could not tell when the eggs were laid or when they were hatched.

It was on March 31, 22 days after I noticed the nest that I saw signs of life in the nest. Every morning at about 8.30 am when I arrived at the clinic, I would notice the pair of parents at the nest. Sometimes one of the birds would be seated in the nest. I had no idea how many eggs were laid until later when the chicks popped their heads out of the nest for me to count them.

At night I was unable to observe which parent bird sat on the nest. What I saw was a bird perched above and near to the nest. When I shone my torch the bird would fly away.

The field guides do not differentiate male and female crows but I was able to tell the sexes apart in that the female had a distinct whitish marking around the neck and was slimmer, whereas the male had a greyish neck and visibly strong neck muscles and stouter. It was the female that spent more time around the nest.

There were in all 3 chicks. The first fledged on 11 April, the second on 14 and the third on 18. On April 26 the chicks were able to fly away from the nest and disappeared for a while.

The chicks had won their ‘wings’ by flying to adjacent trees in the car park. One interesting observation was that when the chicks were about to fledge, a flock of crows came from nowhere and cawed loudly, shouting encouragement to the chicks in the nest. This occurred as each chick took its turn to fledge. That was my first encounter with cooperative rearing of the young. I did not see any crows other than the parents feeding the young in the nest. Lawrence Kilham says in his observations of the American Crow, ”The helpers, sometimes up to six or seven of them aided in all phases of nesting, from nest building to feeding the incubating female, and, after hatching, feeding the young before and after they fledged.”

The incubation period was approximately 22 days from March 9 to 21and it took 27days from March 22 to April 18 for all the chicks to fledge.

On and off for some weeks after, the fledglings would come back to their familiar surroundings on the yellow flame tree. On one occasion I witnessed the same female parent bird with its prominent whitish neck instructing a chick with a morsel of food on the floor, a personal coaching lesson, no doubt.

Three months later, on July 13, a nest appeared suddenly in the same yellow flame tree. On July 21 a pair of crows was seen going in and out of the nest each morning. I presume these were the young crows that had matured and were nesting. Then I looked at the opposite bigger tree near the rubbish depot and found another nest in the canopy. A few days later as I walked to the front of the clinic I spotted another nest in the canopy of another tree. This was the third nest and the pair of crows would fly along this flyway, visiting all the three nests. However, on September 7 the nest near the rubbish dump disappeared without a trace. On September 8 the nest in front of the clinic vanished and the next day the nest in the yellow flame tree was nowhere to be seen. I came to the conclusion that these three nests were trial nests that the pair of young crows was building.

Contributed by Dr Wu Eu Heng, images by YC & WEH

Comments by R. Subaraj: Dr Wu offers a couple of interesting views but more observations are required
before these behaviour patterns can be fully understood and taken as normal. This includes the suggested cooperative encouraging by the group of crows for the fledglings to leave their nest and the trial nests being built by what is
taken as young crows.

Last evening was the sixth day since the nest was built by a pair of House Crows (Corvus splendens) (see 1). A crow was seen hopping in and out of the nest every 5 minutes. Its mate was preening itself a few branches away. Just as the former settled itself in the nest, there was a commotion.

The time was about 7.30 pm, quite dark then. I could make out a large greyish bird perched on a lower branch, slowly and deliberately flapping its outstretched wings. Then I saw another bird a few branches away doing exactly the same. Suddenly both birds appeared above the nest and there was a flurry of wings and what looked like an attack on the nest. This was followed by loud cawing, giving the impression that a crow was hurt. I could not see clearly if there were 3 or 4 birds in that mad scramble around the nest. Just as suddenly, the attacking birds flew off leaving the nesting crow still mournfully cawing away.

There was another shorter attack 15 minutes later. Then 20 minutes later I noticed another bird flapping its wings on the lower branches, but no more raids.

I presume those grey birds must be female Asian Koels (Eudynamys scolopacea), for just before 7 pm a female was chased away by a watchful crow. Also at that time there were koels calling in the nearest of the distant trees.

Tonight it happened again at 7.25 pm!

A crow had just settled onto the nest; its mate had sat in during its 5 minutes break before flying away. A minute later two koels called, and when they were a few branches away the nesting crow flew out and chased them off. The crow cawed for its mate but it was nowhere in sight. Five minutes later a koel was again seen around the nest. Again the crow flew out to chase it away. A female koel suddenly landed on the nest, flapping its wings before it too was chased away.

Did it drop an egg?

The third attempt at the nest saw the koel crying out as it was attacked by the crow. The crow cawed again for its mate after the attack.

Tonight’s episode was not as dramatic as last night’s. All was dark and quiet by 7.45 pm.

Contributed by Angie Ng, 26th December 2005; image also by Angie, taken on the same day at 11.50 am.

Around the time when Angie was monitoring a House Crows’ nest (Corvus splendens) from her apartment window, Hung Bun Tang was doing the same from his apartment balcony. With the aid of a pair of binoculars, he could clearly see a crow sitting in the nest most of the time. However, to check the contents of the nest he had to walk to the next block and station himself at the fourth level. There, he patiently waited for a strong gust of wind to move the leaves blocking his view of the nest. That was how he managed to capture the excellent images included here.

He did just that on 5th December 2005 and again the next day. After a short holiday, he again checked on the nest and my, was he surprised!

In Tang’s very own words: “There is a crow’s nest near my place. I first noticed it on 5th Dec. and saw a naked chick and an egg in it. The next day when I checked it, the chick was gone and I saw only the egg. Then I went off to Taiwan for 2 weeks’ holiday and returned to Singapore on 21st Dec. When I checked the nest this morning, there were 3 eggs!!! I am really puzzled.”

The most probable scenario is that an Asian Koel (Eudynamys scolopacea) raided the nest and removed the crow’s nestling. Subsequently the koel probably laid one or even two of the three eggs he saw on 21st December. Exactly what happened, we will never know, but if he manage to keep close watch of the hatching of the three eggs, we may be able to know whether the above conjecture is true.

Contribution and images by Hung Bun Tang