Spring Notes From Bay Counties
While on a ramble in the foothills south of Novato, Marin county, on March 31, 1902, two white-tailed kites (Elanus leucurus) attracted my attention by their tireless energy in driving away California crows, which are extremely numerous in this section, from a certain oak tree in a grain field. As I approached the spot I perceived in another oak nearby what I took to be the nest. As I ascended the tree the kites began flying in an injured manner to draw me away. The nest proved to be but a few twigs and as one of the birds flew above the tree with a twig in its beak I concluded they were building. On closely examining the other oak a nest about the size of a jay's, caught my eye, thirty-five feet up. Imagine my surprise when I found it to contain three richly marked eggs of this rare hawk, the first to be recorded from the country. The nest, a small, flat, frail structure of twigs and lined with grass, measured eight inches over all, the cavity being six and one-half inches across. It is a striking contrast to a nest found in June, 1899, near Geyserville, which was as large as a crow's nest (cf. Osprey, Volume 4, No, 4). The set was almost fresh and measure as follows, 1.74 by 1.28, 1.69 by 1.31, 1.69 by 1.31. While I was in the tree with the nest the kites retired to a dead tree some distance away, but on leaving they returned and proceeded to drive the ever-present crows away with renewed vigor. On a second visit on April 20 I searched another group of oaks in the field, the old nest being empty. While in one of the oaks the kites became very pugnacious, and starting from a point twenty yards or so away would sail rapidly in a bee-line towards me swerving upward when within a few yards. When I ascended another oak it was a noticeable fact that the kites retired to the dead tree as in the first instance. Although no nest could be seen from the ground I decided to climb the tree and near the top, forty feet up, I found the nest, similar in construction to the first and containing five eggs with incubation just begun. This set gives the following measurements, 1.73 by 1.25, 1.68 by 1.26, 1.62 by 1,25, 1.61 by 1.31, 1.61 by 1.27.
Last year in this region I was rather surprised to find a set of four white eggs, in an old crow's nest in an oak six feet up, on April 6. The nest was lined with feathers, evidently some owl's, and after waiting some hours for the parent I left, as the eggs were cold. This year, on April 6, Ifound a similar nest thirty-five feet up in an oak with five eggs and the parent proved to be the common Nyctalops wilsonianus. On April 20 I found two more eggs in this nest.
On April 13 I took a trip into the San Mateo county foot-hills. Here I came across a strange nest of the western red-tailed hawk (Buteo borealis calurus) in an oak forty feet above the ground. It was a long delapidated structure, scarcely wide enough to hold the single egg it contained and which was far advanced in incubation. Another nest about two miles distant in an oak only twenty-five feet up held two fresh eggs. This female was far more demonstrative than the average and with outstretched wings screamed at me from an adjacent oak .
MILTON S. RAY
San Francisco, California