OLIVACEOUS FLYCATCHER 137 



I have seen no nests or eggs of this flycatcher and can find nothing 

 in print to indicate that it differs materially in any of its habits from 

 the well-known northern race of the species. 



The measurements of 12 eggs average 22.99 by 17.12 millimeters; 

 the eggs showing the four extremes measure 24.3 by 17.0, 22.8 by 17.6, 

 21.3 by 17.2, and 22.6 by 16.7 millimeters. 



MYIARCHUS TUBERCULIFER OLIVASCENS Ridgrway 

 OLIVACEOUS FLYCATCHER 



HABITS 



This is a small, pale race of Lawrence's flycatcher and is the small- 

 est member of the genus found within our borders, not much larger 

 than our common eastern phoebe. Its range extends from southern 

 Arizona southward through western Mexico to Oaxaca. Several other 

 races are found in other parts of Mexico and Central America. When 

 first found by Frank Stephens in the Santa Rita Mountains of Ari- 

 zona, it was supposed to be Lawrence's flycatcher, the type race of 

 the species, but it proved to be a decidedly smaller form, with grayer 

 upper parts, the rectrices only slightly, if at all, edged with pale cinna- 

 mon, and generally paler. 



The olivaceous flycatcher is now known to be a fairly common sum- 

 mer resident of the Upper Sonoran Zone among the various mountain 

 ranges of southern Arizona and New Mexico, especially on the oak- 

 covered hillsides. As to its haunts in the Huachuca Mountains, 

 Harry S. Swarth (1904) writes: 



Though during the summer months the Olivaceous Flycatcher is found in 

 considerable numbers through the lower parts of the mountains; still from its 

 retiring habits, its mournful, long drawn, note is heard far more often than the 

 bird Itself is seen. Seldom venturing into open ground, it loves the dense, 

 impenetrable scrub oak thickets of the hillsides better than any other place, 

 though also found along the canyon streams wherever the trees grow thick 

 enough to prevent the sun from penetrating. It seldom ascends the mountains 

 to any great height, 7500 feet being about the upward limit of the species, and 

 it is most abundant below GOOO feet. They breed down quite to the mouths 

 of the canyons, and on one occasion during the migration I secured one in a 

 wash over a mile from the mountains. This, however, is quite exceptional. 

 These flycatchers begin to arrive early in April, the first noted being on April 

 6, but it is a week or ten days later before they are at all abundant. 



Nesting. — Mr. Swarth (1904) says that "they seem to disappear 

 during the breeding season, and though really very abundant, their 

 plaintive note, heard occasionally from some dense thicket is almost 

 the only evidence that the birds are still around. Consequently not 

 a great deal is known of their breeding habits. All the nests I have 

 seen, some six or eight, all told, were built at a considerable distance 



