SAN BENITO ROCK WREN 295 



when standing, they are seldom quiet, a nervous twitch of the tail or toss of the 

 head bearing witness to the incessant activity so characteristic of these little 

 creatures. 



Voice. — Of the voice Mr. Bryant (1887) writes : "Seldom silent, they 

 have, in addition to their ringing call, a considerable variety of song. 

 I became accustomed to the variations of four or five different birds, 

 and noticed that each had a song peculiar to himself but differing from 

 the songs of his fellows. One little wren near camp was in the habit of 

 beginning his song each morning at about half -past six, never varying 

 five minutes from his self-appointed time. They are usually seen 

 on the ground or upon a rock or stump. One remarkably foggy morn- 

 ing, I noticed one sitting on the top of a sage-bush, while on fine days, 

 I have seen them mounted to the height of 20 feet on a dry cypress 

 twig, singing their cheerful song." 



SALPINCTES OBSOLETUS TENUIROSTRIS van Rossem 

 SAN BENITO ROCK WREN 



Adriaan J. van Rossem (1943) discovered that the rock wren of 

 the San Benito Islands, off the coast of Baja California, Mexico, has 

 a longer bill than the familiar northern type race and gave the above 

 name to the island bird. He says that it is "not distinguishable in 

 color or pattern of tail markings from Salpinctes obsoletus obsoletus. 

 Bill very much longer than that of obsoletus, but at the same time 

 distinctly more slender in both vertical and lateral profiles." 



The "very much longer" bill is a matter of about 3 millimeters on 

 the averaffe; he gives the measurements for 24 obsoletus as ranging 

 from 16.5 to 20.0 and averaging 17.7 millimeters; and for 10 tenuiros- 

 tris as ranging from 19.7 to 22.1 and averaging 20.9 millimeters ; the 

 measurements seem to overlap slightly. 



Family MIMIDAE: Mockingbirds and Thrashers 



MIMUS POLYGLOTTOS POLYGLOTTOS (Linnaeus) 



EASTERN MOCKINGBIRD 



Plates 56-58 



CONTBIBUTED BY AlEXANDEB SpBUNT, Jb. 

 HABITS 



If Mark Catesby had accomplished nothing else in his pioneer work 

 of ornithological discovery in Carolina over 200 years ago but intro- 

 duce the mockingbird to science it would have been a fitting memorial. 

 Had Linnaeus been capable of slang, he might have expressed the 

 opinion, when receiving Catesby's notes on the species, that the collec- 

 tor "had something there !" Truly, that field worker of other days did 



