84 
Heather J. Kalb and George R. Zug 
entering the breeding pond, but no amplexus occurred while GZ was 
present. In 1986, the first major chorus did not occur until 21 April; no 
females were observed on that date. No major choruses occurred in 
1988, although a few males called for the first time on 3 April; because 
no Bufo egg strings were located from April through mid-May, it 
appears that breeding did not occur. 
Air and water temperatures. The means and ranges of temperatures 
observed during breeding were: air 12.8°, 10.0-19.5°C; water 13.2°, 
11.0-17.0°C; N = 10. These data include temperatures recorded sub- 
sequent to first breeding as well as at first breeding. 
Breeding sites. The study area is a suburban park that encompasses 
a small permanent stream and its valley, abutted on the north and south 
by housing developments. The park includes a mix of hardwood forest, 
cattail marsh, and mowed grass tracts. Three aquatic sites are generally 
available for toad spawning: (west to east) a temporary woodland pond 
(ca. 20 m, maximum length), a cattail marsh (ca. 70 m) with lagoon-like 
extensions into adjacent forest, and a permanent man-made pond (ca. 
25 m) at the edge of a recreational field. In 1983, an amplectic pair was 
found in the flooded grass area adjacent to the woodland pond. In 1984, 
amplectic pairs occurred in the marsh and subsequently in the woodland 
pond. First and subsequent breeding activities were observed in the 
woodland pond in 1985. The 1986 chorus occurred in the permanent 
pond. First and second breeding activity in 1987 occurred in the marsh, 
third in the permanent pond, and fourth in the pond and marsh. A few 
males were calling for the first time on 3 April 1988 in the permanent 
pond; during subsequent visits an occasional male was heard in various 
localities, but no breeding was observed in 1988. 
DISCUSSION 
The single recaptured toad with an additional MSG after 1 year is 
not confirmation of the “annual deposition of a periosteal layer” 
assumption. It does, however, indicate that the Eakin Park B. ameri- 
canus produce one MSG each year, and our age estimates are based on 
that assumption. 
The blind protocol for determining the number of MSGs permits 
an evaluation of the legibility of the growth layers and the accuracy of 
the observers. The agreement of our observations for 75% of the toads 
and a difference of one MSG in 21% of the toads indicate a moderately 
high reliability of the counts. The Wilcoxon sign test shows a 
conservative bias for the GZ counts, but it does not invalidate the use of 
the counts for estimating age. To avoid inconsistency, only the HK data 
were used in estimating ages. 
