NO. 7 



PROTECTIVE ADAPTATIONS McATEE 



121 



1906.) Some am])hil)ians have warning colors, l)ut it is noticeable that 

 the nearctic species having such coloration (certain Ainhystoma) do 

 not possess especially noxious secretions, while our toads are not at 

 all warningly colored. The real defense of most amphibians lies in 

 their habits, such as aquatic life, nocturnal activity, and lying in 

 seclusion in burrows or under logs and rocks. Most of the species are 

 very fecund also. 



Bird encuiics. — The extent to which the various families of Am- 

 phibia have been identified from the stomachs of nearctic birds is 

 shown in the subjoined table. 



Identifications of .■linpliibia 



Percentage 

 of species 

 Percentage of of this grou]) 



identifications among 



among those North 



Number of of all American 



firoup identifications amphibians amphibians ' 



Unidentified 132 13-2396 



Urodela (furtlier unidenti- 

 fied) 124 12.4372 



Necturidae 4 .4012 1.4184 



Typhlomoigidae ... ... .0709 



Amphuimidae ... ... 1.4184 



Cryptobranchidae ... ... .0709 



Salamandridae i .1003 2.1276 



Ambystomidae 16 1.6048 14.8932 



Plethodontidae 8 .8024 31.9140 



Sirenidae ... ... 1.4184 



.A.nura (further unidenti- 

 fied) 40 4.0120 



Discoglossidae ... ... .0709 



Scaphiopodidae ... ... 2.8368 



Bufonidae 60 6.0180 9.9288 



Hylidae 77 7-7231 14.1840 



Leptodactylidae ... 2.8368 



Ranidae 535 536605 12.0564 



Brevicipitidae ... ... 2.8368 



While the Ranidae are more abiuidant and accessible to l)irds than 

 most of the other amphibians, even so they seem considerably over- 

 represented in the preceding tabulation, a circumstance that is ex- 

 plained in part by the fact that greater numbers ])roportionally of 

 the stomachs of aquatic birds have been examined than of any other 

 group. 



' Computed from Stejneger, L., and Barbour, T., A check list of Nortli Ameri- 

 can amphibians and reptiles, pp. 5-40, 1917. 



