78 



The Bullfrog, Rana catesbeiana Shaw. 



or for the date of the record, we obtain no maxima below 68 degrees. 

 The average of the maxima for the day previous is 79 degrees, the range 

 68 to 88 degrees; for the day of the 

 record, the average is 76 degrees, the 

 range 68 to 93 degrees. An average 

 of the first records is May 20, but as 

 those for 1908 and for 1911 are voice- 

 records, we suspect the bullfrog first 

 comes out by May 15. 



Of all the frogs this species is most in- 

 fluenced by water-temperatures. The 

 temperatures taken on the water's bot- 

 tom range from 57 to 72 degrees on the 

 day of the record, or average 69 degrees; on the day previous they 

 range from 58 to 73 degrees or average 64 degrees. 



When the air reaches 68 to 75 degrees (certainly at 76 to 79 degrees), 

 we may expect the appearance of the bullfrogs, provided the water- 

 bottoms are 57 to 64 degrees or average 64 to 69 degrees. 



THE VOICE. 



This phase of the bullfrog's life is best known. Its sonorous bass 

 notes have received countless characterizations, among which are the 

 familiar "blood V 'ouns," "br-wum," "be drowned," "more rum/' 

 "jug-o-rum," "knee deep," and "bottle-o-rum." These notes have 

 wonderful carrying power and are 

 commonly heard in the evenings of 

 early summer. They begin about two 

 or three weeks after the frog emerges 

 from hibernation; e. g., in 1906 an 

 interval of 19 days was noted, in 1907 

 the interval was 33 days. Between 

 the first and second voice-records a 

 week or more may pass: 6 days in 

 1908; 15 days in 1911. The range 



of first records extends from May 11 to June 19, the average being 

 May 31. We have a few records in May; the vocal records become 

 frequent in June and reach far into July, usually to its middle. The 

 chorus-stage usually occupies the last of June and first two weeks of 

 July. In 1906 and 1907 the bullfrog was last heard July 15; in 1909 

 on July 18; in 1911 on July 14; and in 1912 as late as August 26. 

 When it approaches the silent period the croaking is not so loud or 

 full. Our first voice-records are shown in the above table. 



The maxima range from 68 to 93 degrees before the record, averaging 

 81 degrees. At the time of the record, they range from 74 to 93 degrees, 

 averaging 82 degrees. The bottom-temperatures of the water for the 



