Natural History of the Racer Coluber constrictor — John Shaqi
Natural History of the Racer Coluber constrictorFitch, Henry S. (Henry Sheldon)
Science
Natural History of the Racer Coluber constrictor
Fitch, Henry S. (Henry Sheldon)
Racer snake
A major problem is that of recognizing movements that involve an
extension of the original range or a shift away from it to a new area.
A few exceptionally long movements were recorded. If these are
included in the computations of home range, they greatly increase the
average distance, probably introducing error. Also, the number of
exceptionally short movements was greater than might have been
expected if all locations of capture are at random to each other. In
some instances a racer newly released may have blundered into the same
trap again, or into the trap at the opposite end of its drift fence.
In other instances traps may have been so strategically situated with
respect to preferred travel routes that they caught the same snakes
repeatedly. In still other instances, the range of an individual might
have been mostly outside the study area, with only one end or corner
overlapping the trap sites.
A total of 471 records for consecutive captures in field areas is
available, 305 for males and 166 for females. In 20 instances
successive sites of capture were the same and movement was recorded as
zero. Of the 471 records, 207 involved a relatively long time span,
including at least one hibernation period; the remaining 264 were
based upon successive records within the same season of activity. The
trends were much the same in the records involving a longer time span
(up to four years) as in those records involving captures made in a
single season, but for the longer periods there were some
exceptionally long movements, and relatively few short movements of
less than 100 feet.
Records of male racers and those of females were used for separate
computations. For each series, the ten per cent of movements that were
longest and the ten per cent that were shortest were eliminated from
consideration in calculation of the average distance between points of
capture. For the remaining 244 records of males an average movement of
595 feet was calculated, and for 132 records of females an average
movement of 574 feet. These distances, if accepted as typical home
range radii, would represent home ranges of 26.3 acres for males and
23.8 for females. In an earlier discussion of spatial relationships in
the racer (Fitch, 1958:119), based upon relatively scanty data, I
estimated the home range to be approximately 23 acres in males. But
with only nine records for female racers I calculated the home range
to be 9.7 acres.
Public-domain text, read in full here on John Shaqi.
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