Northern Prairie Wildlife Research Center
Parasites and disease are rarely mentioned as a serious threat to prairie
grouse, probably due to their mobility and generally lower densities reducing
the odds of completing parasite life cycles. Prairie chickens, being "more
mobile than any other gallinaceous game" (Leopold 1931:176) might be
the least susceptible to disease unless they return to a common feeding areas.
Hamerstrom et al. (1957:79) pointed out, "the need for a system of well
distributed winter feeding places, and gives one more reason for the superiority
of food patches over hoppers and other feeding devices which concentrate birds
in small spaces. Since prairie chickens are subject to several of the diseases
and parasites of domestic chickens and turkeys, food patches should not be
placed on ground over which domestic poultry habitually run."
Gross (1930) gives a fairly complete description of grouse parasites and
diseases with a particular emphasis on another caecal worm, Heterakis gallinae.
He found it in 50% of the prairie chickens he examined in Wisconsin and noted
that it was probably an indication that the prairie chickens had fed on ground
"polluted" by poultry droppings. Of particular concern with this
parasite is that it serves as the host for the protozoan flagellate (Histomonas
meleagris) which causes blackhead disease (Noble and Noble 1973). Gross
(1930:36), who closely studied the heath hen, noted that, "Blackhead
was an important factor in the decline of the heath hen and was probably derived
from turkeys which ranged over the feeding and "drumming" fields
(booming grounds) of the heath hen until blackhead made the raising of turkeys
unprofitable on Martha's Vineyard Island."
Recently, disease considerations have been identified as a contributing
factor in the decline of the Attwater's prairie chicken in Texas (Purvis and
Silvy 1995). Disease investigations are underway with wild populations and
with geese and northern bobwhite quail. Avian cholera and roundworms (Trichostrongulus
tenuis) have been implicated but one of the biggest concerns is the reticuloendotheliosis
virus (REV), a disease similar to AIDS which disables the immune system (Purvis
and Silvy 1995). This virus was found in the Texas A & M University captive
flock and in 1 wild male. Apparently this disease is common in many domestic
poultry flocks (30% of all domestic chickens have it) and wild geese can carry
it (Nova Silvy, personal commun.).
Diseases and parasites have not been investigated with SNG prairie grouse,
nor have they been suspected as a mortality factor. One caution however could
involve the expansion of confinement turkey operations along the south edge
of the SNG; in particular, the disposal of dead birds and manure. If manure
is disposed of in areas accessible to or favored by prairie chickens, this
could be a concern. Perhaps manure should be spread at a time and place when
the likelihood of prairie chicken contact is minimized or it could be worked
in (tilled) soon after spreading. Herman (1963) points out the necessity of
controlling diseases through manipulation of populations and habitat. When
dealing with a population "on the edge", it is prudent to anticipate
all the possibilities for problems in order to take protective measures.