38 Mark S. Davis and George W. Folkerts 



wood frogs in Alabama are slightly enlarged throughout the year, 

 becoming more conspicuously so during the breeding season. Toe web- 

 bing in females remains concave during the breeding season, a condition 

 found in both sexes throughout the rest of the year. 



The call of male wood frogs in Alabama is similar to that described 

 for males elsewhere (Thoreau 1881, Hinckley 1882, Dickerson 1906, 

 Smith 1961, Martof 1970, Minton 1972). It usually consists of two high- 

 pitched croaks or snappy clacks, and may be described as a nasal "back- 

 up," repeated rapidly several times in succession. Solitary males call less 

 frequently, repeating the call only once or twice at varying intervals. 



Calling males float or swim at the water surface with forelimbs 

 hanging down and hindlimbs projecting posteriorly. The digits on the 

 hindlimbs are expanded, exposing maximum webbing surface. In large 

 aggregations, males move and interact frequently (see Wright 1914, 

 Noble and Farris 1929, Wright and Wright 1949, Howard 1980, Berven 

 1981). Calling males are extremely wary and dive below the water sur- 

 face at slight disturbances, concealing themslves under leaf litter and 

 decaying vegetation on the bottom, or hiding among roots or emergent 

 vegetation. When calling from fairly open water, males are nearly unap- 

 proachable. If the pond is small, with emergent vegetation, one can usu- 

 ally approach close enough to observe floating males. Calling males can 

 be heard continuously (though often sporadically) from dusk until 

 dawn, but the chorusing is usually strongest immediately after sunset. 

 Males in almost all Alabama populations call only at night; diurnal 

 choruses were heard at only one breeding pond (W. Baker, pers. 

 comm.). Two lethargic males were collected from the bottom vegetation 

 and leaf litter at one pond during midday. The apparent diel restriction 

 of calling activity is not as conspicuous in more northerly populations 

 (Wright and Wright 1949, Howard 1980, Berven 1981, Waldman 1982). 

 This might be a function of the extremely small population sizes in Ala- 

 bama and the resultant lack of stimulation by large numbers of 

 conspecifics. 



Females in Alabama populations are less conspicuous than chorus- 

 ing males and usually remain below the surface of the water. This 

 behavior is similar to that noted by Banta (1914) and Noble and Farris 

 (1929). Only one female was seen floating on a pond surface; all others 

 collected in breeding ponds were taken under water while in amplexus. 

 Amplexus is axillary (pectoral), with males clasping females just poste- 

 rior to the forelimbs. 



One interspecific amplexing pair was observed during this study — a 

 male wood frog clasping a female R. sphenocephala. When approached, 

 the male released his hold and swam away. The female, partly covered 



