Monday, 29 January 2018

A morning on the Tibetan Plateau in Sichuan: 2. Plateau Pika - another fluffy animal

The Plateau or Black-lipped Pika, Ochotona curzoniae is an animal of, and confined to, the Tibetan Plateau. Ecologists have it marked as a keystone species of the Plateau where it is thought to increase plant growth by aerating and turning the soil through its burrowing. Many predators—like the Pallas’s Cat—rely on this species. Each family has a burrow with multiple entrances and a central nesting chamber.

As we found last November on the Plateau in Sichuan, they are extremely common. We were surrounded by pikas, eating close to a burrow or dashing from one to another. Also extremely common was the White-rumped Snowfinch (Onychostruthus or Montifringilla taczanowskii). We noticed that in areas where these snowfinches settled, the pikas appeared from their burrows. Presence of the finches appeared to assure the pikas that there were no predators near. Snowfinches nest in old pika burrows.

There was another species of snowfinch present in smaller numbers but formed into larger flocks, the Rufous-necked Snowfinch (Pyrgilauda or Montifingilla ruficollis).

Pikas do not hibernate (unlike marmots which had disappeared for the winter). The do make stacks of hay, usually inside the burrow, which they obviously use to supplement their diet of live grasses and herbs, especially in winter. They also have a much thicker, lighter-coloured coat in winter. However, it appears that mortality during the winter is high, with only 1-2% of adults surviving to breed for two years.

Pikas, like all lagomorphs, are coprophagic. They break down their vegetarian diet in the hindgut i.e. beyond the point that some of the nutrients produced can be absorbed. Two types of faecal pellet appear, the normal hard ones that litter the ground and special soft ones which they eat and send through the digestive tract again.

A Plateau Pika eats a lot of grass—61 g/day and there are lots of Plateau Pikas. It has been estimated that in energy intake terms, about 6.2 million kilojoules per hectare are consumed each year by pikas in the alpine meadows of Qinghai-Tibet or 1.3 times that consumed by the domestic sheep kept there*. It is perhaps then not surprising that the Plateau Pika is regarded as an agricultural pest and that they have been, and are being, poisoned in vast numbers in order to protect the existing, and encourage the spread of, livestock industry in China. The damage caused to the grassland, to predator populations and, ultimately, to agricultural productivity itself can be imagined. We see vast areas of natural grassland infested by domestic yaks: the locals see agricultural land infested by pikas and rodents. But we can hardly complain; we have fields upon fields of rye-grass monoculture for our livestock.

My video below shows a Plateau Pika that was filmed from the same position I used for the Pallas’s Cat (see my last post) at an altitude of over 3,500 metres.

*Zhang Z, Zhong W, Fan N. 2003. Rodent problems and management in the grasslands of China. In, Rats, mice and people: rodent biology and management, edited by Singleton GR, Hinds LA, Krebs CJ, Spratt DM. ACIAR Monograph No. 96, pp 316-319