80 Zoology of Colorado 



ing characters of the Ash-throated Flycatcher (Myiarchus cin- 

 erascens), but it is quite a rare bird. The other flycatchers have 

 no very striking peculiarities, but the feet are small in Nuttallornis 

 and Myiochanes, birds formerly referred to Contopus. Sayornis 

 and Empidonax have larger feet; in the former genus the wing is 

 more, in the latter less, than three and one-fourth inches. The 

 tail in Nuttallornis is unusually short. The common species are 

 the Olive-sided Flycatcher (Nuttallornis borealis), the Western 

 Wood-Pewee (Myiochanes richardsoni), Say's Phoebe (Sayornis 

 sayus), the Western Flycatcher (Empidomax difficilis), Brewster's 

 Flycatcher (E. traillii brewsteri) and Wright's Flycatcher (E. 

 wrighti). The Least Flycatcher (E. minimus) and Hammond's 

 Flycatcher (E. hammondi) occur regularly, but are uncommon. 

 The type locality of Say's Phoebe is on the Arkansas River, 

 twenty miles east of the mountains. 



Suborder OSCINES 



Called the "song birds", though they do not all sing. We 

 may first separate the larks (Alaudidae), with rounded tarsus. 

 The Desert Horned Lark (Eremophila alpestris leucolsema of 

 Coues)* is a common bird, known by the two little points or 

 "horns" (really feathers) on the back of the head, and the black 

 band across the upper part of the chest. Although our horned 

 larks are in general of one sort, two others races (E. a. enthymia 

 and E. a. praticola) occasionally occur. 



The remaining complex of families forms an evolutionary 

 series showing a decrease in the first primary feather of the wing, 

 but this orthogenetic process has evidently proceeded along 

 parallel lines, as grades of it may be found within the limits of 

 undoubtedly natural families. In a general way, the birds in 

 which the first primary is reduced to a mere rudiment, leaving 

 only nine to be counted, are those which tend to have thick and 

 short bills, culminating in such forms as the grosbeak. Perhaps 

 v/e should regard the finches in one direction, and the swallows in 

 another, as the apex of avian development. This puts the dom- 

 inant and aggressive English Sparrow in much the same position 

 among birds as man occupies among the mammals, each un- 



*Eremophila is prior to Otocoris, and is not invalidated by the earlier Eremophilus of 

 Humboldt. 



