Relocating animals is a commonly used conservation
technique. In the case of venomous snakes, relocation is often prompted by the
potential for negative human-snake interactions. However, other reasons to
relocate snakes include the re-establishment of extirpated populations, the establishment
of new populations of imperiled species in more suitable locations, and augmentation
of imperiled populations.
The varied
outcomes of studies done on snake relocation suggest the technique remains an experimental
rather than an established conservation method for snakes. The diverse outcomes
reflect the fact that relocation is not a single technique, but a collection of
techniques that vary according to the extent of displacement and the source of relocated
individuals (wild or captive-born). When snakes are moved short distances, such
as might occur when a “nuisance” snake is moved away from the point of
conflict, homing behavior can result in the snakes simply returning to the area
from which they were moved. Short-distance translocation (i.e., relocation of
wild animals within their home range) may also cause snakes to alter their
behavior in ways that increase mortality in some cases, but not in others.
In a new
study, Harvey et al. (2014) conducted
two types of relocation (repatriation and short-distance translocation) using
Eastern Massasaugas (Sistrurus c.
catenatus) in Ontario. For the repatriation experiment, 27 snakes were
captive-born, raised for four years, and released into a nature reserve
previously known to host massasaugas. Other than being relatively sedentary,
snakes behaved normally upon release in that they engaged in reproductive
behavior. Survival was relatively high at 70% until hibernation (19 weeks).
However, none of the snakes that did hibernate (n = 19) survived into the following
active season.
In a
preliminary assessment of the effects of short-distance translocation, snakes
that the researchers moved 200 m from capture locations (n = 4) did not return,
nor did they exhibit abnormal movement or basking behavior relative to
non-translocated controls (n = 7). The different outcomes of our two
relocations could indicate that the success of relocation depends on the extent
of displacement and the source of relocated individuals, although corroborating
evidence is needed before these results can be used to support management
strategies.
Citation
Harvey, DS, Lentini AM, Cedar K, PJ
Weatherhead. 2014. Moving massasasauguas: insight into rattlesnake relocation
using
Sistrurus c. catenatus.
HerpetologicalConservation and Biology 9:67-75.