WASSMER ET AL.: SOUTH-CENTRAL FLORIDA BOBCAT ECOLOGY


helplessly. She was nursing a litter of two kittens at the time. She also
appeared to recover fully from this injury.
 Of the known and probable causes of deaths of radio-collared bobcats in
this study, a substantially higher proportion of mortality was due to natural
than to man-related causes (73% vs. 27%). In generally comparable studies of
radio-collared bobcats in exploited or unexploited populations in other parts of
the range (Alabama, California, Idaho, Minnesota, Oklahoma), natural causes
accounted for an average of about 38% of deaths, with a range from 0 to 100%
(Bailey 1972, Fuller et al. 1985, Gould 1980, Lembeck 1978, 1986, Miller 1980,
Rolley 1985). The present study, in which over half (4 of 7) of the resident
adults were killed by feline panleucopenia in a 4-month period, demonstrates
that the proportion of deaths due to natural causes as well as the actual rate of
natural mortality can be high. Thus, Crowe's (1975) model of the annual cycle
of bobcat numbers which assumes adult mortality from factors other than
trapping to be negligible is clearly not applicable to all populations. It is
difficult to assess the relative importance of various mortality factors for other
than radio-collared bobcats because of a serious sampling bias; there is a
greater probability of recovering animals that have died from man-related
causes, such as shooting or being killed on roads, than animals that have died
from natural mortality agents. In the present study, for example, it is highly
unlikely that the carcasses of any of the bobcats known or suspected to have
died from FPLV would have been recovered if they had not been
radio-collared.
 McCord and Cardoza (1982) noted that documentation of diseases in wild
populations of bobcats was sparse and stated that "...bobcat populations have
not succumbed to epizootics or die-offs due to heavy parasitic infections...,"
citing the commonly reported solitary nature and habits of the species as an
explanation for the apparent lack of infectious diseases in bobcats. In contrast,
our findings suggest that parasites and disease can be important mortality
agents in bobcat populations. The relatively high incidence (24%) of current
or apparent former Notoedric mange infestations in bobcats that were
captured, including F1 who undoubtedly would have died from mange prior to
the study if she had not been treated; the capture of one individual (F2) near
death from a heavy mange infestation; and the probable death of Fl's 1978
litter of four young from mange suggests that heavy parasitic infections can be
a significant cause of bobcat mortality in Florida. Deaths of bobcats from
mange also have been reported in other geographic regions (Pence et al. 1982,
Penner and Parke 1954, Pollack 1949).
 Our study also indicates that feline panleucopenia may be an important
 mortality agent in Florida bobcat populations. Progulske (1982) also
 documented an apparent die-off of bobcats in northeastern Florida during
 summer 1980, which may have been due to a FPLV outbreak. Mortality from
 FPLV also has been reported in bobcats in other widely-separated parts of the