CALIFORNIA SHRIKE 167 



supply of the incubating fenicale would place responsibility for the 

 provision of at least 80 percent upon the male. 



The boldness displayed by the birds when the nest is approached 

 by an observer is highly variable. They are less audacious than 

 when there are young present. Some individuals approach within 2 

 feet, whereas others do not approach within 100 feet or more. Simi- 

 larly, some females tolerate an approach while incubating of 1 or 2 

 feet, others leaving the nest at distances of 50 to 100 feet. Any one 

 bird will vary in its boldness to remain on the nest, depending on the 

 weather conditions, not on the advance of incubation. 



Demonstrations at the nest in an endeavor to repulse an intruder 

 include clicking notes, prolonged jay like notes, schgra-a-a^ and to a 

 lesser degree the customary series of intense screeches of progressively 

 diminishing intensity. Snapping of the bill has been observed during 

 a rush toward the observer. In their excitement the tail frequently 

 is fanned, and also flicked sideways or up and down, the feathers of 

 the back and head are elevated, the body is depressed with the head 

 lowered, and the beak often is held open. Such attitudes are alter- 

 nated with periods of fear when the feathers are adpressed to the 

 body and the head raised accompanying a retreat, or anticipated 

 retreat, to safer distances. The female has been seen suddenly to 

 start begging during the height of her excitement. On other occa- 

 sions shrikes have been seen hovering in the air over the nest tree or 

 about the head of the observer. In some pairs the male is the more 

 active defender, while in others the female is the more aggressive of 

 the two. Nevertheless, when there is no major disturbance in prog- 

 ress, the male is usually the one to chase other species of birds from 

 the vicinity of the nest site. 



Young. — As the young crack open the shells, the greatly dried 

 allantois may stick to the abdomen and cause the lower half of the 

 shell to remain in contact with the bird. Once a female was watched 

 Avhile she sat quietly on the nest on tlie morning of the day when 

 five of the young hatched. She was seen to stand up suddenly, move 

 to the edge of the nest, and then tug and pull at an empty eggshell, 

 which after three or four efforts was freed from the nest, carried to a 

 distance of about 20 yards, and there dropped. 



Young just hatched are bright orange with apricot-yellow bill and 

 foet ; the skin is smooth with few wrinkles and down is nearly lacking, 

 being limited to two single rows of short wdiite neossoptiles on each 

 of the posterior abdominal regions of the ventral tract and a few 

 similar neossoptiles on the elbows. 



For at least an hour after hatching the young bird does not beg for 

 food, but soon after commences to raise the head when it is touched 

 or when the nest is jarred. The margin of the open mouth is con- 

 spicuously outlined with yellow, but the inside of the mouth is a deep 



