SIEBBA CEEEPEE 563 



ture of excess energy really unnecessary? Whatever the answer, the fact 

 is that the creeper, like many other small insectivorous species, whenever 

 seen is always on the go. 



If the bird watcher in the field had to depend upon eyesight alone, the 

 Sierra Creeper w^ould be one of the 'rarest' birds in our forests. Fully 

 half of our own notebook records have resulted from locating the bird 

 first by hearing. The fine and 'wiry' note which it uses as both call and 

 alarm note, see, or zeetle, is given practically throughout the year. In 

 the spring season, there is added the song of the male, a series of notes 

 of the same general character as the call, and of the same high pitch, 

 see', see' , se-teetle-te, see\ The voice of the creeper, especially its call 

 note, is sometimes confused with that of the Golden-crowned Kinglet, and 

 indeed the two are much alike although to the experienced ear there are 

 points of difference. A beginning student should follow up individual 

 birds of the two species and listen to their notes until he learns to dis- 

 tinguish them. It is not unlikely that certain notes of the creeper are 

 so high as to be above the limit of hearing for some persons ; this is known 

 to be the case for the Golden-crowned Kinglet. 



The nesting activities of the Sierra Creeper are carried on in exactly 

 the same surroundings that afford the bird its food and shelter at all times 

 of the year. The space left where a slab of bark has split away from the 

 trunk a short distance, affording a deep but narrow opening, is the place 

 most often chosen to harbor the nest. Such sites are more common near 

 the bases of trees where the bark is thicker and older and the outer por- 

 tions often more furrow^ed and split. It is not surprising, therefore, that 

 creeper nests are often within a very few feet of the ground. Once the 

 site has been selected, both members of the pair busy themselves in bring- 

 ing the materials needed for the nest. The form of the structure varies 

 with the nature of the crevice which has been chosen, but in all cases the 

 general plan is the same. The lower part of the crevice is filled with 

 various kinds of coarse material such as sticks, old flakes of bark, moss, 

 and rotted wood, until firm enough to support the superstructure. On 

 top of this there is made a shallow cup, longer than wide, somewhat the 

 shape of a narrow gravy dish. This part is composed of soft substances, 

 most often weathered shreds of the inner bark of the willow. 



Creepers make direct approach when visiting their nests ; the birds 

 practice no subterfuges for keeping secret their location. Hence it is 

 not difficult to follow a bird directly to its home. This was well illustrated 

 by some observations of ours on a pair of creepers in Yosemite Valley on 

 May 22, 1919. The birds had chosen a location about 12 feet above the 

 ground in a large (30-inch) yellow pine. Entrance to the nest site was 

 gained in this instance through a hole about an inch in diameter in one 



