BLACK-HEADED GROSBEAK 59 



Henry G. Weston, Jr. (1947), writes of its haunts in California: 



Grosbeaks may ordinarily be found in the woodland or in riparian groves and 

 thickets: in these two major types of plant cover, the trees and marginal or 

 understory bushes are used for almost all routine activities. In general grosbeaks 

 are most often found in the open woods. The extensive peripheral foliage 

 characteristic of open woods is advantageous in foraging for food; for singing 

 perches, grosbeaks appear to require fair visibility, and this feature is again 

 best afforded by open woods. Nesting occurs most commonly in streamside 

 bushes and trees and in the live oaks of open woods. Along edges or transitions 

 between grassland and woodland or chaparral, grosbeaks are also common; but 

 they enter chaparral and grassland only infrequently and then only in search of 

 food. 



Mrs. Irene G. Wheelock (1912) adds: "Among the alders that 

 border small streams in the valley, in the cherry orchards at cherry 

 time, in the potato field when bugs are rife, in the oaks and evergreens 

 of the lower Sierra Nevada, one may hear the metallic 'eek, eek,^ of 

 the Black-headed Grosbeak." 



Spring. — According to Weston's (1947) records, the occurrence of 

 this grosbeak in the San Francisco Bay region "is limited normally 

 to the months between April and September, inclusive. * * * The 

 earliest recorded date is April 4, the latest, April 21." The males 

 arrive about six days before the females. They "arrive singly 

 rather than in flocks and are solitary for the few days preceding 

 arrival of females. They begin singing upon arrival, and their 

 activities before the females appear consist largely of foraging in 

 the live oaks and wiUows and uttering frequent songs from exposed 

 perches. Males appear to be spaced, but I saw no conflicts between 

 them until after the arrival of fema,les." 



In the vicmity of Seattle, according to Rathbun (MS,), "one may 

 look for the arrival of this species some time during the earlier part of 

 May. A single bird only may be seen or perhaps several m company 

 loosely associated. By the latter part of May they are mated and 

 the pairs well established in the localities selected for a summer home. 

 And each pair seems to have a defined territory, for we have never 

 found a pair nestmg anywhere near another; and should the locality 

 not be subject to much change, the birds form an attachment for it, 

 continuing to frequent it from year to year." 



Weston (1947) noticed a number of conflicts between mated pairs 

 in defense of their respective territories, in which the females were 

 more aggressive than the males; the females "repeatedly postured 

 and flew at each other, and at each attack, loud songs, calls and 

 sounds of bodily contact could be heard." 



Courtship. — The same observer writes: "The only type of display 

 seen was a nuptial flight. Loud songs were uttered from some exposed 

 perch near a female and then the male would suddenly fly up and out. 



