BLACK-EARED NUTHATCH 53 



birds to gather around, and are usually accompanied by a number of 

 migrating warblers, vireos, etc. Many of them [in Arizona] remain 

 in small flocks up to the middle of May, though others may be seen at 

 work at their nests in some old stump early in April; so by the time 

 the last of them are paired off, those that first went to work are nearly 

 ready to appear with their broods, and there is consequently hardly 

 any time when Pygmy Nuthatches are not to be seen in flocks." 



These flocks of sociable little birds are full of incessant activity, as 

 they drift through the tree tops in loose formations, twittering con- 

 stantly to keep in touch with each other, reminding one of the flocks 

 of bushtits that travel in a similar disconnected way through the 

 shrubbery, yet definitely associated. In some ways, too, their behavior 

 reminds one of the titmice or kinglets, especially in their feeding habits. 



J. Eugene Law (1929) has published an interesting paper on the 

 climbing technique of this nuthatch, well illustrated with photographs 

 showing the specialized use of the feet. He says: "Down-tree prog- 

 ress for a nuthatch seems to be a series of sidling hops or drops. While 

 the bird is moving, its body rarely, perhaps never, parallels the axis 

 of the tree, and at each pause one foot is usually apparent, clinging 

 up -trunk, its grasp transverse to the axis of the tree. When the bird 

 stops, its body may turn so that the body and head point directly 

 downward, and even then there is always that foot up-trunk holding 

 on while the other foot holds the body out from the tree. * * * j^ 

 is obvious, if we think a minute, that in this position the function of 

 the up foot is to cling by the toes, while that of the down foot is to 

 support. * * * The sole of the lower foot is depressed against the 

 trunk wMle that of the upper foot is free." All these points are well 

 shown in his photographs, with the feet widely spread in all crosswise 

 or head-downward positions. 



Very little is known about where and how birds spend their nights. 

 Night roosting of passerine birds has been observed in only a few 

 instances for very few species. From what little has been seen, we 

 might infer that hole-nesting birds may prefer to roost in such cavities, 

 though other methods of roosting have been observed. Mrs. A. H. 

 Jones (1930) watched a family of black-eared nuthatches, in Colorado, 

 go to roost for several nights in a bird box made of slabs and attached 

 to the trunk of a large yellow pine. They came regularly each night 

 at about 6 : 45, entered the box, and apparently spent the night there. 

 But they were not allowed to enjoy this comfortable retreat very long 

 before a house wren appeared one morning and tried to take possession 

 of the box. For a few nights the nuthatches were able to drive out 

 the wren, but eventually the wren secured a mate and filled up the box 

 with twigs, which the nuthatches were unable to remove, and the nut- 

 hatches had to give it up. 



758066—48 5 



