SAGE THMASHEB 547 



Sage Thrashers visit the Mono region only in summer, spending the 

 winter months on the lower deserts to the south. The species was first 

 recorded in 1916 on May 6, one bird being taken near Williams Butte on 

 that date. In 1915 the birds were still in the region in considerable 

 numbers as late as September 20. Censuses during the third week of 

 September, 1915, yielded 2 to 6 of these thrashers per hour of travel within 

 the sage-covered areas, but this included many young-of-the-year. Counts 

 at nesting time would have revealed a smaller number. The birds perch 

 for singing, or for a survey of the vicinity, on the tips of bushes. They 

 are quick to take alarm, and drop to the ground, scudding away on foot 

 until they have so much of the brushland between themselves and their 

 pursuer that they are entirely lost to view. 



Western Mockingbird. Mimus polyglottos leucopterus (Vigors) 



Field characters. — Length about that of Eobin, but build much more slender; tail 

 longer than body and rounded at end. Upper surface plain dark gray, under surface 

 nearly white (spotted in young) ; wing with a large white patch, and tail margined 

 with white, these areas showing forth best in flight. (See pi. 53a.) Voice: Song 

 exceedingly varied; imitates calls of many other birds (whence the name); call note 

 a harsh chuclc. 



Occurrence. — Sparse resident in Lower Sonoran Zone; found at Snelling, and west 

 of Lagrange and Pleasant Valley; casual visitant (December 12, 1915) at Smith Creek 

 east of Coulterville. Lives usually among scattering small trees. Solitary or in pairs. 



Western Mockingbirds are to be found in the orchards at Snelling and 

 Lagrange, and in the scattered blue oaks which intervene between the floor 

 of the San Joaquin Valley and the foothill chaparral belt. The species 

 is by no means so numerous here as in the orange groves of southern Cali- 

 fornia, six individuals being the greatest number seen during any one 

 morning's observations. The open stands of oaks and other small trees 

 seem to offer congenial surroundings to a small resident population. 



More than perhaps any other bird is the mockingbird noted for both 

 variety and loquacity of expression. Its voice is to be heard during most 

 of the daylight hours and often from time to time during the night, as 

 also through a large part of the year. In May, October, and January, 

 visits to Snelling found the species in full song. Only during the season 

 of molt, in summer and early fall, is it quiet. At all other times of year 

 this accomplished mimic exercises its art of reproducing, with large meas- 

 ure of success, the calls distinctive of its various feathered associates. Its 

 repertoire includes excerpts or practically complete reproductions from 

 the vocabularies of a large percentage of the birds in the vicinity. One 

 individual listened to at Snelling on January 10, 1915, imitated, with 

 modifications, the California Linnet, the Western Meadowlark, and Shrike ; 



