48 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



Food. — Mr. Vaiden says in his notes: "We have several chinaberry 

 trees within the town limits, yet I do not find the robins that migrate 

 through the Delta as fond of the berry of the chinaberry tree as I 

 observed years ago in the hill section. I have seen the robin gorge 

 himself with berries until he would fall to the ground; and we were 

 told at that time that they were drunk from eating the berries of the 

 chinaberry tree. 



"I find great concentrations, such as 200 to 300 robins, feeding on 

 the levee after it has been burned over late in the winter; probably 

 the levee has a certain type of soft soil where they find plenty of 

 worms to feed upon. Robins are not great seed-eaters, but I have 

 found many weed and grass seeds in the stomachs of the birds dis- 

 sected. I have found the seeds of Johnson grass, coco-grass, Ber- 

 muda grass, giant ragweed, and dwarf ragweed on many occasions." 



Enemies. — Dr. Friedmann (1934) records two instances in which 

 the southern robin had served as a host for the eastern cowbird. 



TURDUS MIGRATORIUS CAURINUS (Grinnell) 

 NORTHWESTERN ROBIN 



HABITS 



In describing this subspecies, Dr. Grinnell (1909) says that the 

 "full-plumaged male resembles Planesticus migratorius migratorius of 

 corresponding plumage in the matter of size and darkness of colora- 

 tion, the latter being excessive, but lacks the extended white patch 

 on inner web of outer tail feathers; resembles Planesticus migratorius 

 propinguus in the extremely narrow white tippings of the outer tail 

 feathers, but coloration much darker and size smaller. In other 

 words, this new form shares some characters of both, but presents in 

 addition an extreme darkness of coloration seldom or never found in 

 even migratorius. Young very much darker than in either migra- 

 torius or propinguus." 



Dr. Grinnell's specimens all came from southern Alaska, but the 

 race is now known to extend its range southward in the humid coast 

 region through British Columbia and Washington. According to 

 some extensive notes on western robins received from Samuel F. 

 Rathbun, the paler race, propinguus, would seem to be the common 

 breeding form in western Washington, at least in the older and more 

 settled regions of the interior, the darker race, caurinus, occurring 

 there mainly in fall, winter, and spring. "But no line of demarcation 

 can be drawn between these two forms of robins as to their distribu- 

 tion; they intermingle wherever found, although in some localities 

 one or the other may predominate in numbers." 



Based on his 20 years of observation, Mr. Rathbun sums up the 



