Leucocytozoon bonasae Clarke in Michigan Sharp-Tailed Grouse

Abstract

Leucocytozoon bonasae was first described from ruffed grouse (Bonasa umbellus) by Clarke in 1935. That same year Saunders (1935) reported the presence of Leucacytozoon in sharp-tailed grouse (Pedioecetes phasianellus campestris) in Michigan. Since O'Roke (1934) clearly demonstrated that L. simondi could be an important factor in the mortality of ducklings, researchers studying grouse have sought to determine whether L. bonasae may play a similar role in the grouse as a group, particularly with respect to periodic population declines. The majority of the data for this report were collected during the winter and early spring months of 1952 and 1953 as part of an ecological study of sharp-tailed grouse in the Upper Peninsula of Michigan (Peterle, 1954).1 Therefore, the data were derived only from potential breeding populations. Blood smears were obtained from 126 wildtrapped birds, stained with Geimsa's stain, and carefully examined for the presence of blood parasites. At the time of examination, each positive smear was assigned a number to indicate the relative intensity of infection. A rating of 1 indicated that a long search was necessary to locate a parasite; a 2 rating meant enough parasites for rather prompt determination; and a 3 rating was used when a parasite occurred in nearly every field at a magnification of X 100. Gametocytes of L. bonasae were found in varying intensities in 105 of 157 smears examined. Table 1 shows the number of slides examined, the percentage infected, and the average intensity of infection by sex and age classes. The figures indicate that in the study area adult sharp-tails were more frequently infected than juveniles, 72 per cent and 56 per cent, respectively. However, this difference was probably much more apparent than real.