68 BULLETIN OF THE NUTTALL 



1.25 to 1.60 inches. So small, indeed, was this entrance in propor- 

 tion to the size of the bird, that in many cases they were obliged 

 to struggle violently for several seconds in either going out or in. 

 The nests in most instances were very easily discovered, as the bird 

 was almost always in the immediate vicinity, and if the tree was 

 approached would fly to the hole and utter a few low calls, which 

 would bring out its sitting mate, when both would pass to and from 

 the spot, emitting notes of anxiety and alarm. The bird not em- 

 ployed in incubation has also a peculiar habit of clinging to the 

 trunk just below the hole, in a perfectly motionless and strikingly 

 pensive attitude, apparently looking in, though from the conforma- 

 tion of the interior it would be impossible for it to see its mate or 

 eggs. In this position it will remain without moving for many 

 minutes at a time. The amount of solicitude evinced varies con- 

 siderably with different individuals, some pairs showing the most 

 active concern, and keeping up their cries continually, while others 

 take matters more coolly, removing to the nearest tree and watch- 

 ing in total silence the demolition of their home. In nearly every 

 instance, however, when the sitting bird is first disturbed, it utters 

 a cry which almost immediately brings up its mate. Watching 

 once a nest for an hour or two, I remarked that the birds relieved 

 each other in the laboi's of incubation at intervals averaging about 

 half an hour each. The one that had been absent would alight just 

 below the hole, and, uttering a low yeiv-ick, yeiv-ick, its mate w T ould 

 appear from within, when, after the interchange of a few notes of 

 endearment, the sitting bird would fly off and the other instantly 

 enter the hole. 



One very singular fact which I have noticed is that in nearly 

 every tree are several newly finished cavities. In one case four 

 were cut open which had evidently been freshly made, all of which 

 were as neatly and completely excavated as the one that contained 

 the eggs. In addition to these there are often numerous others, 

 which by the dark color of the wood within are shown to have 

 been made in previous years. In one tree no less than fifteen 

 holes were counted, all of which were dug down to the usual 

 depth. Yet in no case have I found more than one inhabited, or 

 noticed in the vicinity any birds other than the pair to which the 

 eggs belonged. These holes for the most part enter the tree on 

 the same side, one above the other, but in some cases the whole 

 trunk is perforated on all sides and at irregular intervals. Possibly 



