Vo1. 25, No. 5 
Page 2 
Table 1. 
mediate, 
Observation rates for hen pheasants captured on the center 
and perimeter portions of the SSA during the fall, 1962-65- 
inter- 
Cohort 
Capture Location 
Center 
Intermediate 
Perimeter 
Juvenile 
(N - 1 ,443) 
33.5% 
23.3% 
21 .k% 
Adul t 
(N = 71*0 
59-3% 
45.4* 
34. U% 
a Pheasants recorded as observed alive were seen at least once 1 January or 
later following capture. 
Ecology and Management of Squ i rrel s - V/-66-R 
C.H. Nixon, 
L.P. Hansen 
Gray and fox squirrels may be studied in the wild because of their diurnal 
activities. Such studies usually include capturing and marking squirrels for 
future vTsual observations. These studies indicate that a he,rarchical social 
structure exists, with adult males, adult females, and young occurring in 
decrea“?ng order of dominance. Little evidence of territoriality has been found, 
although it is commonly stated that a lactating female is territorial around her 
nest site. An indication that territoriality does not exist is the extensive 
overlapping of home ranges of fox squirrels. 
In evaluating the seeming tranquility in tree squirrel populations, one 
might conclude (and several researchers have) that social beb,v '°'' 
limit densities. Unfortunately, we know little about the role sutit1e, unobscr 
interactions play in density regulation. The low and c° n st a nt dens‘ties ot 
squirrels relative to the more cyclic rodents suggests some form of intrinsic 
density regulation. 
Sens i 
indicated 
of young, 
negatively 
mechanisms 
densities, 
standpoint 
population 
squirrels 
densities 
fruitless. 
tivitv analysis performed on data from our work with fox squirrels 
that density changes are strongly affected by production and survival 
Survival of young and reproductive rates were most strongly and . 
correlated with densities, leading us to hypothesize that intrinsic 
, closely tuned to the density of squirrels, may regulate fox squirrel 
A test of this hypothesis is important not only from the biological 
of furthering our understanding of the dynamics of fox squirre 
s but for its management implications. If a population o ox 
is limited by social factors, an attempt to artificially increase 
beyond a point where survival and reproductive rates decline would be 
