The House Crow (Corvus splendens) is a rather aggressive bird (above). At slightly more than 40 cm from the tip of the bill to the end of the tail, this bird is up to 30% larger than the Black-shouldered Kite (Elanus caeruleus). The crow moves in small flocks whereas the kite is usually found singly or in pairs during nesting periods. Only outside the breeding season does the kite feeds and roosts communally. Thus in any confrontation between these two birds, the kite invariably ends up the loser. This is especially so during nesting when the kite is vulnerable to attacks by crows.

Allan Teo is one photographer-birder who has noticed the aggressiveness of the crows. In November 2006 he wrote in saying: “I observed many times that the poor Black-shouldered Kite is always getting harassed by House Crows and many raptors.“ Allan observed a single House Crow harassing the three juvenile kites (above). When one of the kites flew above and hovered around the crow, baring its talons in the process, the latter simply ignored it. Allan also witnessed adult kites being harassed, possibly by Changable Hawk Eagle (Spizaetus cirrhatus) - that may well be juvenile Brahminy Kite (Haliastur indus) (above). Thankfully the attack was only a mock one that concluded with only nerves ruffled. There was another case of these kites being harassed by marsh harriers. He has also seen images of the Steppe Eagles (Aquila nipalensis) that appeared some months ago around the Changi reclaimed areas attacking the nest of the Black-shouldered Kites. In this case the kites managed to chase off the eagles.

Tang Hung Bun reported seeing House Crows harassing White-bellied Sea Eagles (Haliaeetus leucogaster) in Malacca in March 2006. He managed to capture the action on video with the sea eagles rolling their bodies in flight and occasionally managing to turn the table on the crows, chasing them off in the process (1 and 2).

Input by Allan Teo and Tang Hung Bun. Images by Allan except House Crow by Tang.

Crows are omnivorous. This means that they eat anything and everything, from grain, fruits, flower nectar, insects, eggs and birdlings, small mammals and what have you. They are scavengers, thriving where there are scraps of food available. That is why they are so successful around urban areas.

We have posted accounts of crows attacking and eating a rat and a bat. We also have an account of a White-bellied Sea Eagle (Haliaeetus leucogaster) catching a rat swimming in the sea off Changi. But this is the first time we have an account of a House Crow (Corvus splendens) actually fishing.

Meng and Melinda Chan witnessed a House Crow in Punggol last year quietly standing on a rock by the sea. Suddenly it dived into the water and emerged with a fish. With the fish firmly in its bill, it bashed it against the rock until it was stunned or probably dead. Then it started ripping it apart and eating it piece by piece. It was then about 7.00 pm in the evening and the light was low, so the image they managed to capture was not as bright and crisp as they would like it to be.

For the records, there have been reports of House Crows picking fish from shallow water or even plunging into deeper water to fish.

Input and image by Meng and Melinda Chan. Thanks to Kok Hui we have the correct ID of the bird in the above image.

Reference: Madge, S. & Burn, H. (1994). Crows and jays. London: Christopher Helm.

An earlier posting gave an account of the House Crows (Corvus splendens) raiding the nest of the Black-shouldered Kite (Elanus caeruleus) and ending with the crows flying off with anything edible found in the kite’s nest. This account is about the revenge of the kite. The accompanying dramatic images have been captured by photographers Meng and Melinda Chan in Lim Chu Kang some months ago. They have agreed to this post so that more can share their experience.

House Crows are bold scavengers, never letting an opportunity of a free meal go. They would steal any food from anywhere if they can get away with it. This is a story of a crow trying to steal from a juvenile Black-shouldered Kite that was feasting on a rat.There were three juvenile Black-shouldered Kites perching on a tree, one of which had a rat firmly clutched in its left foot. A House Crow spotted an opportunity of a free meal and flew down to perch some distance from the kite. Interrupted from its meal, the kite looked up and suspiciously eyed the crow. The crow moved closer to a nearer branch, eying intensely the rat tightly clutched within the talons of the kite. The crow must have violated the comfort zone of the kite. The kite suddenly lunged at the crow, taking the latter by surprise. The crow retreated and flew off, leaving the kite to continue eating its meal. The last image shows the kite eating the rat with its right wing outstretched, shielding its food from his two sibling as well as the crow, which was still around. Text and images courtesy of Meng and Melinda Chan.

Egg-dumping is the term used by birders to refer to nest parasitism. This is where a bird lays its eggs in the nest of other birds. It can be a bird of the same species (intraspecific parasitism) or of another species (interspecific parasitism). The former is fairly widespread but seldom noticed. However, this can be detected when there are two eggs seen in a day as few birds lay more than one a day. The latter is seen in the Asian Koel (Eudynamys scolopacea) where the koel lays its eggs in the nests of other birds. This is because the koel never builds its own nest.

In Singapore these koels parasitise the nests of House Crows (Corvus splendens) mainly. We had a number of earlier postings by Angie Ng (1, 2, 3, 4, 5) and by Hung Bun Tang (1, 2, 3). Below are some engaging discussions on the subject.

Ong Kiem Sian reported that she saw a cuckoo nesting in a fantail nest. The female cuckoo pecked the egg of the fantail and immediately deposited her egg in the nest. This was completed within a few seconds when the host was not around. She wondered if the cuckoos were desperate and cannot find a host nest, would they then become aggressive, like the koels reported in the postings? She added: “And if the female bird still cannot find and cannot tahan (ie desperate to lay her egg), maybe she will drop her egg on to the ground.”

Yap Kim Fatt countered: “I would have thought the koel chabohs (Hokkien for females) would deposit their eggs in the crow’s nest by stealth rather than by the gangster-ish method as witnessed by Angie Ng (see links above). I would expect a sort of a hit-and-run ova-parturition when the adult crows are not around the nests.”

Jeremy Lee is of the opinion that “If they are nest parasites, I believe they would have to evolve a quick hit-and-run method of depositing the egg in the nest. I have seen documentaries on TV showing cuckoos caught in the act. And it is surprisingly quick to drop the eggs in the nest.”

At the talk in the National Library by Prof NS Sodhi and Ilsa Sharp to launch their book, Winged Invaders – Pest Birds of the Asian Pacific (Singapore: SNP References, 2006) on 10th March 2006, I nearly got my answer to the above. It would appear that the male Asian Koel will seek out an active House Crow’s nest after which he will call out for his mate. Once the female koel appears, the male will approach the crow’s nest whereby the incubating crow will immediately chase it away. At that split second, the female koel will sneak into the nest and lay her egg. The female will then call to signal to her mate that the mission has been accomplished.

But I was unable to elicit a direct response from Prof Sodhi on whether the female koel will drop her egg on the ground if she is not able to immediately find a nest to lay her egg. He believes that in all probability the crow will leave its nest to chase off the male koel, giving the female an opportunity to lay her egg.

Geoffrey Davison has this to say about fertilisation and egg laying: “I had a look at what few books I have at home, but didn’t find anything specific on the time taken from fertilisation of the ovum to laying of the egg by birds. But for all birds, fertilisation has to take place at the top end of the oviduct, before the fertilised ovum is surrounded by albumen, two membranes, and the shell. Since eggs of poultry and many other birds are laid at about one-day intervals, this implies about 24 hours for the egg to proceed down the oviduct.

“Smaller birds lay eggs at shorter intervals, but seldom less than 15 hours or so, and big birds like ostriches would lay eggs at intervals of several days - again, that implies several days for each egg to travel down the oviduct being wrapped in albumen, membranes and shell after fertilisation.

“…It’s also possible that copulation is performed shortly before the laying of an egg that was fertilised by an earlier copulation.”

Input by Ong Kiem Sian, Yap Kim Fatt, Jeremy Lee, Prof NS Sodhi and YC; additional comment by Geoffrey Davison; and images of a female Asian Koel sneaking into the nest of the House Crow by YC

Meng and Melinda Chan, together with two other photographers, were out around the Lim Chu Kang cemetery area on the morning of 6th March 2005 to document the arrival of the male Black-shouldered Kite (Elanus caeruleus) bringing food to the female who was usually sitting in the nest incubating her eggs. The large nest of twigs sat firmly lodged between the end branches of a tall tree, totally exposed all around.

What they witnessed was a sad spectacle. The presumably female bird was perched on a branch near her nest, calling loudly.

This was unusual, as she was always in the nest, guarding her eggs from the constant threat posed by the many House Crows (Corvus splendens) that were around.

The bird then flew to a further branch to join its newly arrived mate. They remained there, not returning to the nest. This was again strange, as they seldom, if ever, left the nest and its contents unguarded. Were the birds stressed in any way? They must have been!

As Melinda described it later, “Our hearts sank when we watched helplessly what was unfolding in front of us.” A gang of four House Crows suddenly appeared. As there were no adult kites around, the crows launched a concerted attach. In Meng’s words, “The crows came in waves, like Japanese kamikazi pilots flying their planes in a series of attacks.”

The crows swarmed over the nest, screaming loudly. They zoomed in one by one to fly off with the contents, including a fully formed embryo and egg shells.

Meng and Melinda then realised that the adult kite they saw earlier, crying out loudly, was in fact crying in sorrow, knowing that the eggs would not complete their cycle and they would not see any nestlings.

Not too long later, when Ming and Melinda returned to the scene, they found the abandoned nest collapsed. But eight months later (November 2005), they found a pair, possibly the same pair, nesting again at the same location, but on a different tree. The crows were a constant threat and the kites had to fight them off all the time. As it was the rainy season then, they did not have much chance to monitor the nesting. The very last time they saw the nest, it was abandoned and was in a bad condition, probably another failed attempt at nesting.

Our bird specialist, R. Subaraj has this to say: These are fantastic dramatic shots that show clear proof of the threat the introduced House Crows pose on native birds. A flock of crows is quite capable of driving a kite off it’s nest to raid it. From one of the image, you can see that the Black-shouldered Kite is actually quite a small raptor compared to the corvid. As our grasslands shrink and the crow population increases, it becomes more and more difficult for the Black-winged Kites to successfully raise a brood. This in turn is a serious threat to the species in the long run.

Note: A detailed account of these kites and their antics when the parent birds arrive with food is given elsewhere by Hilary Hoe.

Text and images by Meng and Melinda Chan.