Page:Condor16(5).djvu/19

Sept., 1914 BIRD NOTES FROM THE SIERRA MADRE 209 food as well as the female. The wrens were the only other members that left the open spaces around the tree, and usually it was only the female, who seemed to do all the feeding. The male spent most of his time on a stub above the nest singing, occasionally making short excursions after food. The other four species spent most of their time around the tree itself; the Chickadees in an untiring search for insects upon the trunk and on the fallen limbs and bark around the base; the Bluebirds and Martins using the higher limbs as stations from which to pursue butterflies, etc.; and the two Swifts taking the stump as a point to circle and dodge around in graceful flight. I noticed that the Swifts had a habit of suddenly darting straight down, as on the angle of a long , and, making a half turn at the lowest point, shoot- ing up again, in an ascent of inconceivable rapidity. As this brings me back again to this interesting bird, I will confess that I am all at sea, as regards this particular instance of unusual nesting. To all appearances the nest which I examined, and which I had seen the Swifts enter a number of times (nine in all, to be exact), was typical of the Tree Swallow (Iridoprocne bicolor) of which I had previously noted several pairs upon the fiats, but none around this particnlar stub. All of the time I was on the snag the Swifts would fly at me, keeping up an angry and protesting twittering; and after I had come down, first one and then the other wonld alight at the hole and either go inside, or wonld hang on the edge for awhile and then fly off again with more excited twitterings. When at rest the white wing patches were very noticeable and also the extra long narrow wings that were crossed scissor-fashion below the tail As there was absolutely no question of identification in this case, the query presents itself, first, what causes had operated to force these birds to choose this unusual nesting site ? And secondly, was this nest entirely of their own making? I say entirely, because I saw one of the birds carry a piece of grass into the hole after I had left the tree. Or had they pre-empted a swal- low's nest, remodeling it to suit their own taste ? Of one thing I am positive, there was no soft vegetable or gummy matter of any kind in the nest compo- sition (I lifted the nest up expressly to see), such as I have seen mentioned by all writers on the subject before. In answer to the first question, I can only note a few facts that may bear upon the subject. In an area of eight or ten miles around the fiats, there are very few cliffs that would fill the needs of these birds, those which are of any extent presenting few cracks or fissures that wonld serve as nesting sites. One exception of which I have knowledge is, or rather was, until the winter just passed (when a rock slide shaved it absolutely bare), a large broken mass of granite, high up on the slopes of Strawberry Peak (in the Big Tujunga Range) situated a short mile or so to the northwest of the extreme western edge of Barley Flats. Here in previous years I have observed numbers of the Swifts during the breeding season, but the nature of the intervening country has pre- vented a closer investigation. One other place where I have noted them in the breeding season is on the back slopes of San Gabriel Peak near the headwaters of the West Fork of the San Gabriel River. In preceding years the species has been fairly abundant along the rocky wails of the canyons here, but this year they have evidently been driven from their usual haunts by the heavy blasting which has been done, incidental to driving a new trail through the canyon. If our birds were some that were accustomed to nest in either of the places mentioned, or if an earlier nest in some more legitimate site had been by some cause destroyed, it might