They were also more destructive than quadrat searches because the area searched encompassed a greater range. Time-constrained searches can be quite important though, if a particular species is located only in specific microhabitats. Shrews and, less commonly, mice and moles are sometimes found dead in these traps. Pitfall arrays catch more small mammals than pitfall transects for the same reasons that they catch more amphibians. This problem can be solved by digging out the nest.
Pitfall traps can fill with water or become completely dry.
Both of these problems can cause amphibian mortality. Species of anurans can survive in water-filled traps whereas P. cinereus and Notophthalmus viridescens drown. However, if traps dry out, some amphibians can become dehydrated and die. Moist moss was placed in the traps to prevent mortality, however, without frequent trap checking, some mortality is inevitable. Some amphibian species can escape, such as Pseudacris crucifer and P. cinereus .