THE CACTUS WREN 73 



walk of about a mile over a cactus-strewn, 

 rocky detritus fan emerging from one of the 

 desert canons, I once counted thirty nests. 



Last spring a nest was made within twenty 

 feet of my door and I had a chance to watch 

 closely the rearing of the young. Incubation 

 began after four salmon-dotted, white eggs had 

 been laid in the nest. When once hatched the 

 baby birds, like all youngsters, grew amazingly 

 fast and their appetites kept the mother con- 

 stantly afield in search of insects. It seemed 

 only a few days from the time I first saw the 

 tiny, upstretched, gaping mouths until the 

 nest was overflowing with squirming almost 

 full-grown birds. The passageway or vestibule 

 to this nest was very short — not over four 

 inches long — and it was always a wonder to me 

 that none of the restless birdlings became im- 

 paled on the frightful cactus needles bristling 

 like bayonets about the edge of the nest. After 

 making inquiry for a number of years, I can 

 find only one instance where young were seen 

 spitted on the thorns outside. 



The wrens are peculiar among birds in that 

 among many species there is the habit of build- 



