WASSMER ET AL.: SOUTH-CENTRAL FLORIDA BOBCAT ECOLOGY


general, mutual use of areas by adult bobcats of the same sex was confined to a
narrow zone along the line of contact of their current home range boundaries.
 Bobcats apparently only rarely came into close contact with neighbors of
the same sex. Only four cases of two adult males or two adult females being in
close proximity were recorded during the study. Daytime rest sites of females
F4 and F1 were within 200 m of each other on one occasion in December 1979,
and F4 rested near F8 on one day in October 1980. These two females also
walked within 100 m of each other one night in August 1980. The only instance
of two adult males being close together was recorded in October 1980, when
M8 followed M6 about 2 minutes behind along a stretch of railroad track, then
each veered off in a different direction.
 Death or disappearance of a resident bobcat resulted in major changes in
the size and shape of home ranges of adjacent animals of the same sex. In
contrast, opposite-sexed survivors did not exhibit such a response to the loss of
a neighbor. Thus spacing mechanisms may operate independently in males
and females. Three clear-cut examples and a probable fourth case of this
phenomenon were documented. After the death of M2 in late October 1979,
adjoining males M1 and M3 expanded their home ranges into the area of M2's
former range, whereas the boundaries of the female (Fl, F3, F4) ranges
remained stable (Fig. 3B, C). The apparent expansion of Fl's range reflects
better sampling in the subsequent time period and not an actual change in
movements. M3 died in mid-January 1980, and his death was followed by
further expansion of Ml's range but no obvious changes in those of females
(Fig. 3C, D). Female ranges also remained stable following the death of Ml in
early February 1980 (Fig. 3D, Fig. 4A). The most dramatic male range
expansion documented was that of M6 in late July 1980, following the death of
an unmarked adult male on the north boundary of his range (Fig. 4C, D).
Female ranges also showed an apparent slight increase during this period,
which is believed to reflect changes in their movements related to age of their
young rather than an actual expansion in response to the increase of M6's
range. In the single case of a confirmed death of a female (F10, late February
1980), one (F4) of two neighboring females markedly expanded her range into
the vacated area (Fig. 4A, B). The other female (Fl) was also subsequently
located in the former area of F10, but data available on F10 up to the time of
her death were not complete enough to definitely establish the boundary
between the home ranges of these individuals.
 Range expansion of adjoining same-sexed bobcats began a short time after
 the death of a resident. In six cases, such shifts were first detected within 5-14
 days, with a mean of 9 days. There was no significant difference (U2,4 = 4,p >
 0.05, 2-tailed) between sexes in the time before the first recorded incursion into
 the new area. Home range boundaries in the invaded area appeared to be
 realigned within several weeks with no evidence of "jockeying" for position.