Demography and migratory patterns of the eastern long-toed salamander

The breeding migration of the eastern long-toed salamander, Ambystoma macrodactylum columbianum, was studied at a small pond in NW Idaho using a drift fence and pitfall traps. During the period of 27 Feb.-25 April 1983, 2030 adult salamanders (1054 males and 976 females) were intercepted at the drift fence. The timing of migratory events was influenced by a combination of environmental and biological factors: 95% of all migration occurred when the minimum air temperature was 0 C or greater and 78% of all migration occurred on days with measurable precipitation. The pattern of migratory movement was either continuous or episodic, depending on the prevailing pattern of air temperatures and precipitation. Female salamanders arrived at the breeding pond later than males and appeared to leave the pond soon after oviposition; male emigration began shortly thereafter. No preferred migration routes with respect to various measures of habitat quality (i.e., habitat type, relative soil moisture, or vegetation type) were evident. Individual salamanders, however, did tend to use the same habitat for immigration and emigration. Based on the computed sampling efficiency of the drift fence, population size was estimated at 3141 adult salamanders (1986 males and 1155 females) in a 1.7:1 male: female sex ratio.