86 Geinnell, Sequestration Notes. [j" n 



in numbers up to a dozen or more in one tree, such as a blossoming 

 eucalyptus, or in a clump of fruiting Rhus laurina. But the indi- 

 viduals in all such gatherings show themselves to be thoroughly 

 independent of one another; each goes his own way; and there is, 

 indeed, frequent evidence of friction or conflict of individual inter- 

 ests. There is no indication of coordination of movement, as with 

 truly flocking birds: no individual advantage is gained by the 

 gathering. 



Observation of any one Ruby-crowned Kinglet under the usual 

 winter-day conditions in southern or west-central California, shows 

 it to be almost continually intent upon its search for insects. Its 

 mode of search, and the category of insects which its equipment 

 fits it to make use of, direct its forage course as a rule through thick 

 leafy terminal foliage of evergreen trees and shrubs, less generally, 

 perhaps, among the stems of willows and alders, where, however, 

 there are usually left-over, curled-up leaves, and plenty of crannies 

 behind buds and in clefts of forking twigs, to harbor small insects. 

 But insects are relatively scarce in winter, increasingly so as the 

 season advances; and the Kinglet's scrutiny must be rapid. Each 

 individual Kinglet must cover much territory in limited time in order 

 to gather the food in sufficient quantity. 



As it thus forages, each Kinglet every now and then utters its 

 note, or series of notes. Another individual, or others, may be 

 heard from time to time in the distance, but I have failed altogether 

 to receive the impression that two or more birds "answer one 

 another." My experience is that they most certainly do not come 

 towards one another as the result of such calls. And here the idea 

 presents itself, logically, that these notes serve to keep the foraging 

 birds apart: they are scqxiestration notes. 



The nature of the conditions which call forth this category of 

 notes, which makes them of use in the struggle for existence on the 

 part of the species, would seem to me to be as follows. The King- 

 let is a foliage forager and is most of the time within or in close reach 

 of adequate cover; hence for the most part it is safe from both aerial 

 and terrestrial predators. It relies for food upon small insects, 

 mainly stationary, which in the winter season are not abundant, 

 sometimes exceedingly scarce, as shown by occasional periods 

 when some of the birds starve; the Kinglet cannot dig after its 



