The breeding migration of Smooth and Palmate newts (Triturus vulgaris and T. helveticus) at a pond in mid Wales

Abstract

The breeding population sizes of newts at Llysdinam Pond in 1981 are estimated at around 800 Palmate and 300 Smooth newts. Females were more numerous than males with sex ration of 3.0: 1 for Palamte and 2.6: 1 for Smooth newts. The movement of males of both species into the pond preceded that of females, and female Palmate newts moved out of the pond significantly later than the other classes. The number of females of both species leaving the pond was much less than the number entering, apparently as a result of mortality whilst in the pond. Females leaving the pond were significantly lighter than those entering, and for female Palmate newts the weight loss in only partly attributable to loss of egg load. Temperature and humidity were important factors influencing the number of newts active during the inward migration period, but had little effect on activity during the outward migration.

Breeding Dynamics, Diet, and Body Condition of the Hong Kong Newt (Paramesotriton hongkongensis)

“…We observed some variation in timing of breeding at different sites, but the overall pattern was consistent in all four populations and contrasted sharply with that of most amphibian species in Hong Kong (Karsen et al, 1998;Dudgeon and Corlett, 2011) and most other salamander species in temperate regions (Harrison et al, 1983;Duellman and Trueb, 1994; , 1996), in which breeding migrations typically coincide with increasing rainfall or water level (Healy, 1975;Semlitsch, 1983; and temperature (Verrell and Halliday, 1985;Palis, 1997) during the spring or summer. Although the precise climatic cues for the onset of migration could not be determined, breeding migrations of P. hongkongensis appeared to be inversely related to rainfall and water temperature.…”

Conditions controlling the timing of the autumn migration to hibernation sites in a Japanese headwater frog, Rana sakuraii

“…Licht, 1969;Koskela & Pasanen, 1974;Gittins, Parker & Slater, 1980;Douglas & Monroe, 1981;Wisniewski, Paull & Slater, 1981) or rising temperature as well as rainfall (e.g. Tester & Breckenridge, 1964;Hurlbert, 1969;Harrison, Gittins & Slater, 1983;Petranka, 1984;Semlitsch, 1985). In addition, humidity (Bellis, 1962) and lunar phase (lunar cycle) (FitzGerald, 1974;Grant, Chadwick & Halliday, 2009) have also been advocated as factors affecting migration.…”

Bayesian analysis of Jolly-Seber type models

“…However, the models are more generally applicable as other species and animals arrive or emerge in groups and exhibit heterogeneity in their survival or detection. For example they could apply to data sets of amphibians collected at breeding ponds, with different groups expected to arrive at different times (Harrison et al 2009, observed male newts arriving before females), and in addition to have different detection and/or retention probabilities.…”