478 LIFE HISTOEIES OF NOETH AMEEICAN BIEDS. 



are usually located in bunches of the same material. But those of either form 

 of the Hooded Oriole, when built of yucca fibers, might be readily mistaken for 

 each other. Besides the trees already mentioned, Mr. Scott found it breeding in 

 sycamores, and in California; it nests in walnut, willow, cypress, gum, and fan 

 palms (Washingtonia filicera), the fibers of which, according to Mr. Theo. D. 

 Hurd, are almost exclusively used as nesting material in that locality. 



Mr. Hurd published the following interesting notes on the nesting habits of 

 this Oriole, as observed by hint in that vicinity: "For the rearing of the first 

 brood the nests are usually suspended in overhanging branches of the blue gum 

 (Eucalyptus globulus), but it is a noticeable fact that the second nests are more 

 commonly attached to the leaves of the palm tree. Why this is I do not know, 

 unless they want to begin laying as soon as possible, and therefore build where 

 material is most easily obtained. When in palms the nests are fastened directly 

 to the under side of a large leaf, leaving a small opening on one or more often 

 on either side, for the bird to enter." 1 



Mr. R. H. Lawrence took a nest of this Oriole containing four eggs near 

 Monrovia, California, on May 19, 1893; this nest, which he kindly sent to me, 

 was attached to the under side of a banana leaf, about 9£ feet from the ground. 

 Two other nests were subsequently met with in similar situations, one of these 

 probably belonging to the pair whose eggs had been previously taken. 



Two and possibly even three broods are sometimes raised in a season. I 

 found slightly incubated eggs in Arizona on August 25. From three to five eggs 

 are laid to a set; in Arizona usually only three or four; but Mr. Hurd reports 

 taking a set of seven on May 6, 1890. An egg is deposited daily until the set is 

 completed. The Arizona Hooded Oriole is imposed upon to a considerable extent 

 by the Dwarf Cowbird, and I found several nests containing one and two eggs of 

 this parasite with one or two only of the rightful owner. 



Incubation lasts from twelve to fourteen days. I do not know whether the 

 male assists in this duty, but have seen him carrying nesting materials. The nest 

 is well built, it is basket or cup shaped, with a very thick bottom and strong 

 sides. It averages about 4 inches in height externally. The inner cup is oval, 

 about 2£ inches deep and 3 by 2 inches wide, and it takes about four or five 

 days to complete it. 



The eggs resemble those of the Hooded Oriole in general shape and ground 

 color, but a few approach a decided elongate ovate; as a rule they are better 

 marked, and the darker shades predominate over the lighter ones; they also 

 show more of a tendency to run into zigzag markings, as do the majority of 

 Oriole's eggs. 



The average measurement of thirty specimens in the United States National 

 Museum collection is 21.59 by 15.37 millimetres, or about 0.85 by 0.61 inch. 

 The largest egg in the series measures 24.13 by 15.24 millimetres, or 0.95 by 

 0.60 inch; the smallest, 18.03 by 13.21 millimetres, or 0.71 by 0.52 inch. 



i Ornithologist and Oologist, Vol. XV, 1890, p. 13. 



