Population monitoring of Svalbard rock ptarmigan (Lagopus muta hyperborea): point count survey of territorial males in spring

Hovedmålet til prosjektet er å utvikle, etablere og gjennomføre en lang tids overvåking av Svalbardrype for å oppdage endringer i bestanden og trender over tid.

Rationale: The Norwegian Polar Institute (NPI) is through our allocation letter responsible for the long term monitoring of the Svalbard rock ptarmigan (Lagopus muta hyperborea) population on Svalbard. The Svalbard rock ptarmigan is the only land-inhabiting bird which resides in Svalbard throughout the year. It is listed as an indicator species for monitoring of terrestrial biodiversity in Svalbard.

The Svalbard rock ptarmigan is monitored because:

  1. it is an endemic sub-species which imparts special management responsibilities for Norway,
  2. it is the most important small game species for hunting, and
  3. current ecological knowledge is limited

Background: Knowledge about population dynamics in Svalbard rock ptarmigan is limited due to lack of long-term data series. Currently there is very little information about the population size and variation in abundance of the Svalbard rock ptarmigan. Factors that could drive ptarmigan population cycles are not studied in Svalbard. Both climate and predators are suggested as important factors determining chick production, but fluctuation in numbers may also be caused by a combination of many aspects including climate change, parasites, social factors and hunting. In 2000 the NPI initiated, in cooperation with the Governor of Svalbard, an annual population monitoring programme for Svalbard rock ptarmigan.

Point count surveys for 20 minutes from approximately 160 set geographical positions separated by 1km are conducted up to 3 times during 3–4 weeks in April. The survey region (approx. 1000km2) is located in the two main valleys, Adventdalen and Sassendalen. Relative densities of males are calculated using Distance Sampling methods. No population estimates exists for the archipelago, but since 2000 the number of territorial cocks in the survey region has varied between 1 and 3 birds per km2.Since 1997 hunters have reported data on numbers of ptarmigan shot, date and location for hunting and delivered one wing for age determination to the Governor of Svalbard. Since 1997 between 500 and 2000 ptarmigans are harvested annually. The primaries (three outermost feathers) are used for age determination and the data on age are used for calculation of production (juveniles per pair). The production estimates since 1997 has varied from 3 to 5.5 juveniles per pair. We have digitalised all the previous data up to 2008, and they are now available for analyses. The monitoring data will be analysed in order to elucidate the relationship between population size, climate variation and harvesting of Svalbard rock ptarmigan.

Within the NPI, Åshild Ønvik Pedersen (Biodiversity section) is participating in the project. This work is conducted in cooperation with the Governor of Svalbard, UiT The Arctic University of Norway (formerly “the University of Tromsø”), and the Norwegian Institute for Nature Research (NINA), Tromsø.

This NPI project has received financial support from the Governor of Svalbard (2000–2007) and the Svalbard Miljøvernfond (2008).