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Mar., 1918 THI? SALT MARSH ,?LOWTHROATS O1' SAN I*RANCISCO 63 densed form of two syllables; but the power of it rises rapidly as the year ad- vances until by the end of March its nuptial gladness pours forth in full-throated volume. Sometimes as evenin.g approaches, one of the little blaek-faeedbirds ?vill leap into the air with fluttering wings and expanded tail and as it slowly tumbles down into the grass again, will execute an exquisite series of melodious runs and trills not unlike the voekl accomplishments of the Chat. The nesting period ranges from middle April until June, fresh eggs having been taken on April 2 and June 18. The yellowthroats, habitually suspiei0us, be- come doubly vigilant during the breeding season and I think that only twice in all the years I have studied them have I surprised the female in the act of earry? ing nesting material. It has been my experience that if an unfinished structure not containing eggs is located, ?he birds promptly abandon it. The nest, a cup- shaped, fairly compact receptacle is usually eomposed of lengths of dried grass well interwoven with the s'upporting stems. It is commonly hidden in bunches of wire grass or weeds among willows and placed from six to twenty-four inches above the ground. The bowl-like interior is often lined in rather a loose manner with dried grass or thin fiber. The usual complement is four though a set of three, particularly when laid late in the season, is not rare. The eggs are taper- ingly oval in shape, 'white, with a decided pink tinge when fresh, and eireularly splotched about the larger end with dots and dashes of black, brown, and deep lavender, varying in size from minute markings on some specimens to a pro- nouneed ring of eelor on others. Ineubation, which is performed by the female, us'ually occupies'about fourteen days. There has occurred of recent years a serious factor which may possibly, ?f long continued, result in permanent changes in the nest-building of these birds. It has become a custom of the Italian truek gardeners who cultivate the upper hills of Merced to make frequent exeursions down to the lakes to cut the tough wire grass in which sinuosa nests, in order to use it for binding vegetables, thus economizing in cord. For this purpose the grass is eelleered in enormous quan- tities, great swathes being opened through the thickest growths and in other places entire meadows being utterly denuded. As this destruction takes place during the time when eggs and young are in the nests, it is reasonable to .conclude that numbers of these are annually destroyed. It has lately appeared to Mr. It. W. Carriger (and my observations would tend to confirm his conjecture), that as a result of this persecution the yellowthroats are nesting less abundantly in the grassy flats and adapting themselves more to life in the inaeeessible rules of the open lake, or else building their homes higher up toward the banks amid thickets of blackberry and willow. Certainly the number of sets found in these localities is far greater now than in former years, and in time such safety zones may be 'used exclusively. While incubating, the females often show remarkable shyness in slipping off the nest and keeping well ahead of the observer, with short undulating flight. Oeeasionally as evening approaehes they are apt to flush from directly beneafi? one's feet, particularly should he beat quietly up toward them against the wind. When startled from her nest the female disappears and maintains silence for some moments but if the intruder remains in the vicinity, or removes the nest or eggs, her sharp chack of alarm will rapidly summon the male and the pair will flit nervously about in the underbrush, often fearlessly approaching within a few yards of the observer.