During rain storms when pitfall traps are used to capture amphibians, nontarget species may be incidentally captured and drown as the traps fill with water. To reduce mortalities of nontarget species, we designed floating shelters for use in pitfall traps. The shelters are constructed of polystyrene with a walled base and suspended cover. Cotton batting was placed in these shelters as bedding material. The structures were placed in 16 pitfall traps for 10 consecutive days. Incidental captures included western harvest mouse (Reithrodontomys megalotis), California vole (Microtus calfornicus), southern alligator lizard (Elgaria multicarinata), and western fence lizard (Sceloporus occidentalis). All rodents and 2 lizards were found alive in the shelters, and 1 lizard was found alive under the shelter. Rain did occur during the trapping period, although traps collected no more than 10 mm of water. Despite the rainfall, the shelters and the cotton batting remained dry, except for the shelter used by the California vole. Modifications of the materials may be necessary to insure structural integrity. The shelter design succeeded in providing a refuge for reptiles and small mammals and may help researchers reduce the number of unnecessary mortalities in pitfall traps.
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