PARENT SESSION
Friday, August 11, 8:00-11:30 am
COS 108 - Species movement and dispersal
L-5, L-6, L-7, Lobby Level, Cook Convention Center
Presiders: A Boyle
Ecology of resident and relocated northern red diamond rattlesnakes (Crotalus ruber ruber).
Brown, Tracey*,1, 2, Lemm, Jeff2, Tracey, Jeff3, Montagne, Jean-Pierre2, Alberts, Allison2, 1 California State University, San Marcos, San Marcos, CA, USA2 Conservation and Research for Endangered Species, San Diego, CA3 Colorado State University, Fort Collins, CO
ABSTRACT- Northern Red Diamond Rattlesnakes (Crotalus ruber ruber) have a very restricted range in the United States and are considered a species of special concern in California. We used radio-telemetry to collect data on the movement ecology and habitat use of this little-studied species over a five year period (1999-2004), on protected coastal sage scrub land managed by the Wild Animal Park (Zoological Society of San Diego). For both the safety of snakes and visitors, Park staff routinely relocate nuisance rattlesnakes away from animal enclosures and pedestrian paths. We used these opportunities to gather data on the movement patterns and survivorship of relocated C. r. ruber ("Relocates"; N=6; 3,858 radio-days) for comparison to "Resident" snakes (N=11; 11,090 radio-days). Among Resident snakes, activity range sizes varied greatly both between individuals, and between years within individuals. Male Resident activity ranges (minimum convex polygon) were typically triple the size of Resident females (2.88 ha vs. 0.88 non-gravid females or 0.76 ha gravid females), and Resident males moved nearly twice as far during an activity season (1.38 km, Resident males vs. 0.78 km, Resident females). Relocated snakes (three relocated short-distances, < 500 m; three relocated long-distance, > 500 m) used significantly more land (mean 5.8 ha, range 1.6 to 14.9 ha), and had greater maximum per move and total distances traveled during the first year after relocation than did Resident snakes. Activity range sizes, annual distances moved and mean movement speed decreased over time among the short-distance relocated snakes, yet was similar or increased among the long-distance relocates. The majority of Residents locations were associated with rock outcrops or boulders; in contrast, Relocated snakes were found primarily associated with vegetation (no rocks). Unlike most previous studies of relocated rattlesnakes, there was no significant difference in survivorship between Resident and Relocated rattlesnakes.
Key words: rattlesnake, relocated, movement