162 BULLETIN 19 7, UNITED STATES NATIONAL MUSEUM 



both birds suddenly jumped into the air, the defending "male" came 

 within striking range, and a series of sharp clicks of the bill and a 

 few screeches, low buzzing notes, and staccato vocal notes were heard. 

 The flight of the two continued for a few yards, when the defender 

 returned to the "female," which had remained quiet and seemingly 

 undisturbed throughout the performance. The repulsed invader tow- 

 ered in a most erratic manner and flew high over the hills at the edge 

 of the valley half a mile away, apparently most intent on departing 

 with rapidity. 



In each territory there is usually what may be termed a head- 

 quarters. The roosting place, so far as known, is situated here and 

 usually also the nest, if the territory is used for breeding purposes. 

 The headquarters provides good lookout perches, feeding facilities, 

 and some sort of bush or tree for shelter at night. It is occupied 

 during a large part of the day. In many territories, nevertheless, 

 subsidiary headquarters exist. If one wishes to locate a shrike in a 

 known territory, a search in two or three favorable localities usually 

 reveals the bird's presence. Evidently, therefore, all parts of the 

 territory are not used equally, yet territories are defended in their 

 entirety. 



The requisite for roosting places seems to be some support above 

 the ground within a screen of overhanging limbs. Eoosts are marked 

 by conspicuous fecal deposits. In one instance the nest was built 

 within 6 feet of a roost that had been used for a considerable period 

 previously by the female. The male roosted about 15 feet away in a 

 similar location among dense limbs, the site not being well marked 

 probably owing to his recent arrival on the territory. Arrival at the 

 roost is commonly 35 to 40 minutes after sundown and departure in 

 the morning about half an hour before sunrise. 



Courtshif. — Two aspects of courtship should be recognized. The 

 first type of activity apparently serves to reinforce the pair's bond. 

 It does not immediately lead to copulation and it normally occurs 

 early in the season. Typical is the following : On January 24, mem- 

 bers of a recently mated pair were seen sitting one foot apart on 

 a telephone w^ire. The birds flew from the wire, one closely following 

 the other. Upon alighting on a fence one of them gave a series of 

 screeches of the usual rhythm but of a peculiar metallic quality, a 

 note found to be associated always with nuptial activities. The two 

 birds then hopped and flitted back and forth from fence wires to 

 fence post in what might be called a mock pursuit. After perching 

 quietly for several minutes on the fence, one bird attempted to alight 

 on the post occupied by the other shrike, whereupon the two again 

 engaged in mock pursuit. Still later one of the birds crouched near 

 the other, fanned its tail, and at the same time tipped its tail upward. 

 This action was followed by more of the metallic screeching, the per- 



