Pellets from Tuas: 10. Black-shouldered Kite’s prey and bone fragments in the pellets
By Melinda Chan, Chan Yoke Meng & YC Wee, 6th June 2015;
On 12th February 2015, Melinda Chan collected two pellets from Tuas, around the area where the pair of Black-shouldered Kites (Elanus caeruleus) was nesting.
One pellet was larger than the other: 55x30x25 mm as compared to 21x20x15 mm. The larger was oval and very tightly packed in hairs. The smaller was disk-shaped, 21x20x15 mm, also covered with hairs but not as tightly packed.
The larger pellet was somewhat smaller than an earlier one that contained a complete skull, believed to come from a Common Barn Owl (Tyto alba).
However, on dissecting this larger pellet, there was no skull, only bone fragments from the head that included jaw bones, loose molars, an incisor, vertebrae, etc. But there was no complete skull. So in all probably the pellet came from a kite that had fed on parts of the mouse head and not from an owl.
Pellets from Tuas: 8. Black-shouldered Kite feeding chicks
By Chan Yoke Meng & Melinda Chan, 13th April 2015;
The ground below the nest of the Black-shouldered Kites (Elanus caeruleus) is often littered with carcases of mice and numerous pellets. The image above shows a headless mice found below the nest. An intact mouse was also found below the nest.
We believe they fell from the nest when brought in by an adult. We had observed that within minutes on the ground the dead mice would be covered with ants. Thus returning it to the nest would introduce ants and pathogens. Another reason these fallen mice were not retrieved can be that there were no shortage of mice in the area.
Pellets from Tuas: 4. Analysis of 14 pellets
By Melinda Chan, Chan Yoke Meng, YC Wee & Wang Luan Keng, 9th March 2015;
Melinda Chan made extensive collections of pellets from a tree-lined avenue in Tuas in January 2015. All pellets were covered with short grey hairs, most probably those of mice. One of these was larger than the rest, from which a near-complete skeleton of a mouse was extracted. This was the only pellet that had an intact skull, all others had bone fragments and numerous loose teeth but no skull.
This large pellet was thought to have come from a Barn Owl (Tyto alba). The others, all smaller, were believed to have come from the nesting pair of Black-shouldered Kite (Elanus caeruleus), most probably the chicks.
However, an initial examination of four pellets left a big question mark on the identity of the prey – as no skull was found. The presence of numerous molars and bone fragments that had holes of various sizes and shapes, added to the mystery of the prey identity. After all, the mouse bone fragments failed to deliver any loose teeth and these strange “holey” fragments.
Subsequently 14 pellets were examined following earlier protocol. No complete skull was found in any of hese pellets. Many had the same types of fragments found in the earlier four pellets. In addition, pieces of jawbones with some teeth still attached were found and there were numerous loose teeth, molars actually, as well as incisors. An attempt has been made to label some of the bone fragments.
The number of bone fragments collected totaled 86. These included a skull, lower jaws, dislocated skull bones, ear capsules, shoulder blade, long bones, ribs, vertebrae, foot bones, toes, claws, etc.
The presence of a skull with the characteristic positioning of the incisors and molars, with a wide space in between (above), confirms that the bones belong to that of a rodent, most probably a mouse as the molars have cusps.
Pellets from Tuas: 1. The Pellets
By Melinda Chan & Chan Yoke Meng, 20th February 2015;
The casting of pellet by certain groups of birds is not too well known– see here for more information. After swallowing their prey, these birds regurgitate the indigestible parts that were compacted in the gizzard in a form of pellets. These pellets collect on the ground below the trees where the birds normally perch. Ornithologists collect and study pellets to get information of what the birds had been eating.
Of late, Melinda Chan had been collecting these pellets while Chan Yoke Meng was busy photographing the Black-shouldered Kite (Elanus caeruleus) along the tree-lined avenue in Tuas.
The image of the the exposed pellet clearly shows the bleached bone fragments.
Together with the pellets on the ground were carcasses of half-eaten rodents.
Brown Rat (Rattus norvegicus)
Tampines, 30th December 2014
Due to the relatively short tail, it’s likely that this carcass belongs to the extremely common urban species known as the Brown Rat (Rattus norvegicus), also sometimes known as the Common or Norway Rat. Despite its name, its original native range is believed to be northeast Asia.
Singapore Rat (Rattus annandalei) carcass at Old Upper Thomson Road
Location, date and time: Singapore Island, Old Upper Thomson Road; 8 June 2013; 1258 hrs.
Observation: A crushed carcass of about 27 cm (head-and-body length) was found in the middle of the road. See accompanying photograph with a Singapore ten-dollar note for scale.
Remarks: The Singapore Rat is distinguished from other rats in Singapore by its sharply demarcated white underside, brownish throat and uniformly coloured tail. It inhabits secondary forest and scrubland (Baker & Lim, 2012: 140). The example featured here was most likely killed and flattened by the tyres of a motor vehicle while it attempted to cross the road from one forest patch to another.
Baker, N. & K. K. P. Lim, 2012. Wild Animals of Singapore.A Photographic Guide to Mammals, Reptiles, Amphibians and Freshwater Fishes. Updated edition. Draco Publishing and Distribution Pte. Ltd. and Nature Society (Singapore).180 pp.
Brown Spiny Rat (Maxomys rajah) carcass at Chestnut forest
Location, date and time: Singapore Island; Central Catchment Nature Reserve, Chestnut forest, Gangsa Track alongside the Bukit Timah Expressway between the entrances of the Kranji Expressway and the Zhenghua Flyover; 9 July 2014; 2025 hrs.
Observation: A carcass of a male Brown Spiny Rat with head-and-body length of 19 cm and tail length of 17.5 cm was found lying in the middle of the trail. The specimen was stiff and covered in ants. The animal has been deposited in the Zoological Reference Collection of the Lee Kong Chian Natural History Museum, at the National University of Singapore.
Remarks: The Brown Spiny Rat inhabits rainforest habitats, and is regarded as an endangered species in Singapore.
Lim, K. K. P., R. Subaraj, S. H. Yeo, N. Lim, D. Lane & B. Y. H. Lee, 2008. Mammals. In: Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds.). The Singapore Red Data Book. Threatened Plants & Animals of Singapore. Second Edition. The Nature Society (Singapore). pp. 190-270.