BIRDS OF THE REGION 151 



March 10, 1924. It is not improbable that this species 

 may spend much of the winter here or at slightly lower 

 levels, using the caves for protection from cold and 

 storms, as well as from the extreme heat of summer. 

 Early in April the pair of birds occupying the cave shaft 

 were found to have a nest about thirty feet below the 

 surface, but in an inaccessible opening in the rocks 

 where the eggs and young could not be seen. The 

 birds were often seen at the nest, and later were regu- 

 larly carrying food to the noisy young. Jim White 

 told me that they have nested here every year since 

 he has known the cave, about twenty-three years. 

 Others were found nesting in three other caves nearby. 

 These records together with their well known habit of 

 nesting down in the shafts of old wells indicate their 

 fondness for subterranean protection. Apparently they 

 do not go back to the dark parts of the caves, but stay 

 in the cool, shadowy shafts, where there is a dim light. 

 During March and April both of the nesting birds 

 above mentioned regularly entered the shaft at night 

 to roost in the warm cave air safe from outside enemies. 

 As great numbers of moths and other insects also take 

 refuge in these warm shafts, the birds may find an 

 important part of their food here, even in cold weather. 

 In fact, caves and caverns seem to account for the 

 presence of these flycatchers in surprisingly cold winter 

 climates. 



Horned larks migrate through the Pecos Valley, and 

 one or two of the forms stay to breed out on the open 

 parts of the plains country and on top of the Guadalupe 

 Mountains. 



