Page:Condor21(2).djvu/19

 Mar,, 1919 BIRD NOTES OF A STORMY MAY IN COLORADO SPRINGS 65 Aside from the migrations, the most interesting observations, I think, were on the Say Phoebes, which stayed about feeding on insects over the sur- face of the water, and then disappeared as soon as the weather became fairly good. The little flock of Scaups staying so long on the pond was also some- what remarkable. As I have remarked above, the number of Myrtle Warblers was extremely unusual. Colorado Springs, Colorado, January '6, 1919. LOSSES SUFFERED BY BREEDING BIRDS IN SOUTHERN CALIFOl{NIA By H. ARDEN EDWARDS NY EFFORTS at estimating the probable increase or decrease of our na- tive birds must take into consideration the very considerable loss sus- tained by them during their breeding season.. A record of such known losses shows a surprising percentage of eggs and young birds destroyed during any one year, and the careful observer will at once notice a certain number of contributing causes which are fairly constant. Taking these different factors in the order of their importance, we find that predatory mammals and birds hold first place. Preeminent among mam- mals is the common house cat; but the weasels, skunks, and coyotes also figure importantly. When I write predatory bird, my mind does not picture at once some noble falcon or swift flying raptor, but rather that skulking robber of the woodlands, the California Jay. Next as causes of loss come 'the rare storms of wind and rain, which, while of short duration, bring widespread damage, espec- ially to nests and eggs. Thirdly, there is the ignorance and carelessness of man, which adds no small amount of destruction to the general total. And lastly, we may include the partial sterility of the birds themselves. I say par- tial, as I have never come across an instance where an entire clutch of eggs was lost from this cause. To return to the first factor, we will naturally expect to see the preponder- ance of effect exerted here. Nature is always destructive in a constructive sense. Everything is sooner or later destroyed that something else may live. Death is written large upon every bird. The blossom only fulfills its purpose when it has faded and made way for the perpetuating seeds. So it is in bird life also; a bird may fulfill a purpose when it furnishes a meal for .a wild ani- mal; but when it falls prey to a tame cat, I fear Nature has been cheated. Nature surely intends that no one species shall prey to excess upon some other species; therefore, the specialization which is evolved in the way of pro- tective coloration, and defensive organs and habits. Take,' as a specific in- stance, the orioles. The South American branches of this family have devel- oped some remarkable methods of defense, such as that of the Caciques--which suspend their nests only in trees containing the nests of a very pugnacious spe- cies of wasp. Gadow tells us that in Mexico'certain orioles have learned to tie their nests to the telegraph wires, where it is almost impossible for anything without wings to reach them. Our own North American species of oriole have learned to construct nests which insure a degree of safety, even from the ,narauding owl.