Friday 21 October 2022

Impala in the Masai Mara of Kenya


This male Impala (Aepyceros melampus) in the Masai Mara of Kenya was engaged in 'tongue flicking' when we photographed him in September 1991.

Monday 17 October 2022

Tokay Geckos in Hong Kong: wild and/or feral populations?

Tokay geckos are known to occur on the island of Lantau, in the mainland New Territories and on Hong Kong island. The new paper on the trade in Tokay geckos in Hong Kong I referred to in a previous article found suggestions that at least one of the populations in the New Territories contains the red-spotted morph, indicating a non-Hong Kong origin and likely the result of introduction either by escape of captive geckos or deliberate release. The authors concluded:

Our genetic analysis shows that TCM [traditional Chinese medicine] trade in Hong Kong is not likely supplied by local wild populations, but by imports from Southeast Asia. Additional information from SIA [stable isotope analysis] supports our genetic findings, as we detected very little overlap in isotopic signatures between TCM and Hong Kong wild tokays. Trade also leads to mixing of populations through introductions related to the live pet trade. We found that at least two Hong Kong wild tokay populations were likely established from released pets. 

The conclusion that Tokay Geckos are not now collected from the wild in Hong Kong suggests a change has occurred since the first discovery of Tokay Geckos in the wild on Lantau Island on 23 February 1950 since that discovery was only made when the source of live geckos for sale in a snake shop came to light.

The grand old man of Hong Kong herpetology, John Dudley Romer (1920-1982) wrote in the journal Copeia:

On February 23, 1950, I purchased a live adult Gekko gecko from one of the snake-dealers, and on making enquiries regarding its origin, was informed that it had been received from Tung Chung. A few days later I visited that locality with some friends and enquiries on arrival at once revealed that this gecko is well-known to the local Chinese. One live adult specimen was obtained from a woman who had apparently been keeping it to sell in the city. Since time was short we engaged one of the villagers to show us exactly where the geckos were found, and after an hour or two of stiff climbing, he finally halted on a rocky hillside and pointed out several narrow clefts in some particularly large rocks. It was then only a few minutes before we saw one of these giant geckoes in a cleft in one of the rocks.

John went on to suggest that the gecko may have been more widely distributed in Hong Kong since it had not been found in the typical habitats of this species, in northern Burma for example: “houses, huts and trees and at nights are often seen on fence posts. In forests they live in holes or on the bark of trees.” He concluded:

It seems likely that their absence from dwellings and apparent confinement to the rocks on lonely hill-sides in this colony may be related to their extermination from other types of habitat.

In other words, he was suggesting that the population on Lantau was a relict of a once much wider distribution across Hong Kong. The discovery of a second population on Lion Rock in the New Territories could give credence to such an explanation.

When the second edition of Hong Kong Reptiles and Amphibians was compiled and published in 1998, the populations on Lantau and on Lion Rock were considered native; it seems that conclusion still holds.

Those arriving or leaving Hong Kong by air will, if sitting on the side nearest the mountains of Lantau will be passing the site John Romer described. However, his fishing village of Tung Chung is now  the nearest town to the Chek Lap Kok airport with a population of over 1000,000 and still rising. If tourists ever return Hong Kong, the Ngong Ping Cable Car links Tung Chung to the Po Lin Monastery and Big Buddha. The once difficult to reach village is now just another stop on the MTR.

The page on the Tokay Gecko from Karsen, Lau and Bogadek's
Hong Kong Amphibians and Reptiles

Dufour PC, Miot EF, So TC, Tang SL, Jones EE, Kong TC, Yuan FL, Sung Y-H, Dingle C, Bonebrake TC. 2022 Home and hub: pet trade and traditional medicine impact reptile populations in source locations and destinations. Proceedings of the Royal Society B 289:20221011 

Karsen SJ, Lau M W-N, Bogadek A. 1998. Hong Kong Amphibians and Reptiles. Second Edition. Hong Kong: Provisional Urban Council. ISBN 962-7849-05-7

Romer JD. 1951. The occurrence of the lizard Gekko gecko in the colony of Hong Hong. Copeia 1951, 80.

Thursday 13 October 2022

Hong Kong Dragonfly: the female version in gold


This one from AJP seems to be the work of a Mr Auric Goldfinger before his demise at the hand of Bond, James Bond. However, it is probably a female Common Blue Skimmer, Orthetrum glaucum. I showed the pruinescent blue male in my last post.

Monday 10 October 2022

A pruinescent Hong Kong Dragonfly

 A weekend photograph came from Hong Kong of a common species there, the Common Blue Skimmer, Orthetrum glaucum.

The blue colour is not a blue pigment but created by Tyndall scattering of light in wax particles secreted on the surface (pruinescence) of the dragonfly.