Blood parasites in sage-grouse from Nevada and Oregon.
Peripheral blood smears from 196 adult and yearling female greater sage-grouse (Centrocercus urophasianus) were examined for blood parasites (167 from the breeding and 29 from the brood-rearing season) to determine prevalence of blood parasites, to attempt to correlate infection with chick survival, and to establish base-line values of prevalence in sage-grouse from Nevada and Oregon (USA). Birds were captured and released on two study areas during 1999-2001; Sheldon National Wildlife Refuge (SNWR) in northwestern Nevada, and Hart Mountain National Antelope Refuge (HMNAR) in southeastern Oregon. Birds from a third study area, Beaty's Butte grazing allotment (BB) in southeastern Oregon, were sampled in 2000 and 2001. Overall, 19 birds (10%) were positive for Leucocytozoon lovati (= L. bonasae), 1 (0.5%) for Plasmodium pedioecetii, and 2 (1%) for microfilariae. Although prevalence of L. lovati on HMNAR was 39% during the breeding season in 1999 and 100% during the brood-rearing season in 2000, statistically, prevalence of L. lovati among study areas and years was not different. However, there were statistical differences between capture periods. Overall, 31% of the hens were positive for L. lovati during the brood-rearing season compared to 6% during the breeding season. There was no difference in packed cell volume between infected and non-infected birds and no difference between age-classes. However, mean sage-grouse productivity on HMNAR was higher (1.6 chicks/hen) for non-infected (n = 10) compared to infected hens (0.7 chicks/hen; n = 7), during 1999. Based on these limited observations on HMNAR in 1999, the possible effects that L. lovati may have on young sage-grouse could be detrimental to sage-grouse populations in Nevada and Oregon.
Dunbar
Mike R
MR
US Fish and Wildlife Service, Sheldon/Hart Mountain National Wildlife Refuge Complex, Biological Investigations Unit, P.O. Box 111, Lakeview, Oregon 97630, USA. mike_dunbar@fws.gov
Tornquist
Susan
S
Giordano
Mark R
MR
D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000469:parasitology; D001717:Birds; D005260:Female; D016787:Haemosporida / Q000302:isolation & purification*; D006400:Hematocrit / Q000662:veterinary; D009505:Nevada / Q000453:epidemiology; D009922:Oregon / Q000453:epidemiology; D018512:Parasitemia / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D010961:Plasmodium / Q000302:isolation & purification; D015995:Prevalence; D011529:Protozoan Infections, Animal / Q000453:epidemiology* / Q000469:parasitology; D012098:Reproduction; D012621:Seasons