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 66 THE CONDOR VoL XVIII They always slipped quietly through the brush back of the nest, coming into view almost directly under it and on the ground, and then mounting to it from t;vig to twig. When visited at 7:30 A. rL March 25, the nest was completed and neither bird was in evidence. It was a rather deep cup-shaped nest, compactly but lightly built, and laced, for its principal support, 21 inches from the ground, to the side of a perpendicular stalk of teasel coming up through the clump of bac- charis, a few smaller twigs serving to steady it. The materials used in its con- struction were weed and bark fibers and dried grass, with a thin inner lining of dried grass and horse hair. The following measurements were made after the young had left and when the nest was slightly distorted and otherwise rather the worse for wear: Outside, depth 2.75 inches, diameter 3 inches; inside, depth 2 inches, diameter 2.90 inches. Fig. 28. WREN-TIT ON ITS NEST From March 25 until March 30 there was no change in conditions, and neither bird was seen near the nest. The weather turned cold and rainy during this interval and it is possible that further opera- tions were delayed on that ac- count. March 31 at 4 r. rL one egg was in the nest. Coin- ci,dent with this the weather had become warm and dry. On April 1, the nest contained two eggs. One bird, assumed to be the female, was flushed from the nest; the other was singing nearby. April 2, at 4 r. rL, there were three eggs in the nest; female (?) flushed, other bird not seen. April 3, 5 r. M., no change. Parent bird flushed from nest. April 4 no change. A note was made at this time which perhaps suggests why so few wren-tits' nests are found. The bird remains on the nest, which is well concealed in the leafy portion of the bush, and is only flushed when the twigs within three or four inches are disturbed. Then, instead of a demonstration against the intruder or an attempt to lure him away, she slips quietly over the side of the nest and is gone, taking full advantage of any cover that can be found. April 5, 5 P.M., parent bird sitting close on nest From this date until April 20 incubation was carried on, one or the other of the pair being upon the nest practically all the time. The photographs accompanying this article were taken April 9, when the bird proved to be a fearless subject. April 20, when observed at 7:30 A.M., all the eggs had hatched and the nest contained three young. Thus the length of the period of incubation (from the laying of the third egg) was eighteen days, or figuring the time from April 5, from which date one or the