178 ('iiifcrsitji itf Califdniia riiblicatidiis in Zdoldc/ij |Voi.. 12 



river, although the Hues of ciitelaw or palo verde would seem to offer 

 congeuial cover. The Ahert towhee seems to be closel_y bound to the 

 viciiiitv (iT water, in sjiite of its evident ailai)lation in eolor and 

 strueturc to a region oL' desert conditions. 



Although we were camped almost continually witiiin tiic ri|)arian 

 strip, we saw no evidences of the nesting of this species until April 

 27, on wliieh (late near I'otholes a half-grown Juvenal was fdund. 

 This, liowever, appeared to be exceptional, as many adults in pairs 

 were to be seen. A juveual was taken near Pilot Knob, May 14, 

 where, again, there were no further evidences of nesting. In 1908, 

 ]\ruseum collectors found the Abert towhee around the northwest end 

 of Sallon Sea, wliere nests were found [)leutifiilly in .\|)ril; and in 

 the same k)cality in ]!)11, \'au l\os.seni (llMl, p. liiti) found eggs 

 March 20 and 21. It would appear tliat the Aliert towhee, as in 

 the case of the song sparrow, has along the Colorado River deferred 

 its regular time of nesting luitil relatively late in the season, so as to 

 avoid the period of rising Hoods. 



A series of forty-six specimens (nos. 13;U0-13385) obtained by 

 the present expedition shows striking luiiformity in external char- 

 acters: that is. individual variation both in res[>eet to color and size 

 lies within very nariMW Iniits. TakinLi- a single feature: twenty-two 

 adult males show a wing iengtii of 8!).!) to !J5.1 millimeters. The 

 average is 92.3, Die mid-imint of th(> range is 92.5. and the variation 

 (S-U'h side of the mid-point is but 2.8 per cent. Tn twenty-one adult 

 fenudes ihe average wing length is 8().8 niiiiimeters: tlie extremes are 

 83.0 and 89.4, the mid-point of the range is 8t),2, and the variation 

 on either side of the mid-point is 3.7 per cent. 



Three specimens are in the Museum (nos. 4115—4117) taken by 

 J. G. Cooper at Fort Mohave, February 19 and April 4 and 24, 1861. 



Oreospiza chlorura (Audnbon) 



tireen-tailed Towhee 



First seen ]\lareh 14, on the Arizona side above Bill Williams Hiver, 

 one or two individuals: next April 7, on the same side ten miles 

 below Cibola, two seen; tlum April 15. on the California side twenty 

 miles north of I'ieaelio, se\-er;d : two were si'en Api'il 2t) on the 

 Arizona side, five miles north of Laguna ; and one, on the California 

 side, Ma.v 4, five miles northeast of Yuma, and May 8 and 10, one 



