Hong Kong urban wildlife of the rodent kind

Last week, AJP in Kong Kong spotted these animals in Haiphong Road, Tsim Sha Tsui. They had not been spotted by passing tourists or local commuters. They appear to be young Buff-breasted Rats, the taxonomy of which seems still uncertain. They are often called Rattus flavipectus or included in Rattus tanezumi, sometimes as a subspecies, Rattus tanezumi flavipectus. They used to be Rattus rattus flavipectus.

It is interesting that they do not appear to be Brown Rats (Rattus norvegicus). Both species occur in urban Hong Kong and the Urban Services Department used to have rat bins mounted on lamp posts for people to drop trapped dead rats in. They and the fleas they carried were examined for plague bacteria. Kong Kong had a major outbreak of plague in 1894, as part of the third pandemic. The last outbreak was in 1929. The causative organism of plague was, as is well known, discovered in Hong Kong by Alexandre Yersin during the 1894 outbreak.

Anybody familiar with Hong Kong will know that Haiphong Road runs between the old docks area to the west of Canton Road and Nathan Road. Hence the 1960s and earlier, Brown Rats might have been expected as the more likely sighting. However, Haiphong Road is adjacent to Kowloon Park, the site of the old Whitfield Barracks. In much of its range the Buff-breasted Rat is said to favour villages with surrounding countryside. Perhaps this rat population is centred on the park.

Henderson Island Rats: nil desperandum

One of the most disappointing pieces of news this year came from the RSPB (Royal Society for the Protection of Birds). The massive international effort in 2011 to rid the Pacific island, Henderson, a British possession in the Pitcairn group, of rats had not been successful. However, the reports indicate that the population had been greatly reduced and that the colonies of nesting seabirds were recovering as a result.

The Polynesian or Pacific rat (Rattus exulans) was introduced during the expansion of the Polynesians across the Pacific. Henderson was abandoned but the rats, identified as a major predator on nestling sea birds, remained. Quoting from the Henderson Island News (Issue 5):

Rats have had a devastating effect on the island, killing over 25,000 petrel chicks a year and driving the Henderson petrel towards extinction. Seabirds, which would have numbered in the millions before rats arrived, have beenreduced to just 40,000 pairs. Rats have also been limiting the populations of other endemic bird species, altered the forest through seed consumption, and preyed upon marine turtle hatchlings and Henderson’s unique invertebrate populations. 

The job of covering the island 43 square km in area with rodenticide (while capturing, holding (and breeding) Henderson rails in captivity until the exercise had been completed) while operating a long way from everywhere was a very great effort and attracted financial support from around the world, as well as from the UK government.

We visited Henderson on October 2010 on MV Clipper Odyssey during a Noble Caledonia Expedition Cruise from Easter Island to Tahiti. By the time we got to Henderson we had visited Ducie Atoll, also in the Pitcairns, now apparently rat free, with its incredible seabird colonies but no land birds. Henderson has its few land birds and some seabirds but in nothing like the numbers on Ducie. While looking in the undergrowth behind the beach we saw a rat and I managed to get a few seconds of video footage. It clearly had not read the information on this species stating that it is nocturnal.

I hope efforts to remove the rats will continue at this World Heritage Site and that those who provided financial support (including many individual RSPB members and expedition cruise passengers and the travel company Zegrahm Expeditions, as well as government and other charities) will continue to do so. Just seeing the contrast between Ducie and Henderson was enough for me to conclude: ...whatever it takes.