16? THE CONDOR Vol. XXI an open pasture.. Although the tree was fairly thick, the nest was deserted be- fore an egg was laid. Whether due to my having discovered it, or the result of its position, ! have no way of telling. ! discovered the nest at a distance of about twenty feet from the tree and did not approach any closer until ! re- turned for the set, when ! found the nest deserted. The nest is placed from seven to twenty-five feet up, and well out at the end of a branch, usually very well concealed. As a matter of fact unless dis- covered building the nest is almost impossible to locate. On one occasion I dis- covered a nest by the fact that its occupant, presumably the male, was singing while on the nest. I judge this to be a rather uncommon occurrence. The nest blends so well with its surroundings that sometimes, even though 1 have for- merly located the nest, I have had difficulty in locating it again. It might be well here to describe one or two negting sites, to give a fair idea of their normal location. ! found one nest, March 13, 1918, by following the building birds. It was located in a small live oak tree about seven feet from the ground. I.t would have been impossible to have seen it from any angle except directly above, unless led to it by the birds. Fronds of Spanish moss hung all about it, part-of one frond being woven into one side of the nest. The nest was on the west side of the gee. Another nest, more usual in location, I found on March 8, 1918, It was about sixteen feet from the ground and about the same distance out from the trunk, near the end of a large branch in a clus- ter of foliage and moss. An unusual nest was one located in a manzanita bush under a live oak. This nest gave .my companion and me a bad hour or two be- fore we located it; we must have passed by it at least three times before it was discovered. This is the only instance that has come under my observation, of the bird building in other than a live oak. The usual complement of eggs is four, sometimes three, very seldom five. ! believe Mr./-L W. Carriger has one set of five taken by Mr. Gurnie Wells in Sonoma County. This is the only set of five ! have heard of. The ground color of the egg is pearly white, dotted with reddish l?rown spots and specks at the larger end. The ground color never varies, but the number and distribution of the spots is seldom alike in any two eggs. In one set of three in my collection, one egg is pure white with very few minute specks on it; the other two have only a few slight markings. In most of the other sets ! have, the markings are typical. The eggs vary somewhat in shape and size, some sets being slightly round without being distinctly larger at one end than the other, while others are elongated and larger. ?bout two weeks after incubation is started the nestlings are hatched and by the time the month is out they are ready to take their first trials of flight. The nestlings are fed by both parents during ther stay in the nest. ! watched four fledglings being fed for a period of about an hour; they were visited every ?ive minutes on an average during this period. The nestlings were partially covered with feathers at the time and were keeping the parents very busy fill- ing their hungry mouths. I have given some study to bird population in this territory and cstimate ?hat in associationally good country a hundred breeding pairs to the square m?le is a. fair average. The area of Sonoma County is fifteen hundred square miles, and of that area about two hundred and fifty are well sprinkled with live Oaks. This would give about twenty-five thousand breeding pairs of Hut- ton Vireos in Sonoma County. I consider this really to be a low estima?.e. Here
