Phenological Differences in Wood Frog and Spotted Salamander Egg-Mass Onset and Peak Accumulation

Abstract

We used egg-mass counts to monitor populations of Lithobates sylvaticus (Wood Frog) and Ambystoma maculatum (Spotted Salamander) at 4 ponds located in central Vermont. We monitored numbers of egg-masses for 15 springs over the course of 20 years (2000–2020). Each year, the number of Wood Frog egg-masses at our breeding sites increased rapidly, over a period of close to 2 weeks. Spotted Salamanders deposited eggs beginning about a week later than the Wood Frogs, and the number of their egg-masses increased at our study sites over a period of up to 8 weeks. Consequently, when using egg-mass counts to determine presence/absence or to monitor populations, it is important to take the relative phenology of these 2 species into consideration.