Ptarmigan (Lagopus muta) Science Article 9
abstract
Sympatric populations of tetraonid birds tend to fluctuate in synchrony, at least onlocal scales. If shared parasites among sympatric populations of different tetraonidspecies are to operate as a local, synchronizing factor for population fluctuations atleast two conditions should be met
Per R. Holmstad, Peter J. Hudson, Vigdis Vandvik and Arne Skorping, OIKOS 109: 429-434, 2005