116 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



lOtli. For nesting sites the California live oaks are leading favorites, but tlK: 

 birds nest indifferently throughout the scrub * * * to the tops of the ranges. 

 Manzanita, Christmas berry, hoUyleaf cherry, ironwood, mountain mahogany, 

 scrub and VVislizenus oaks, and Monterey pines, all serve as hosts, therefore, with 

 little preference save for shade. Nests, although bulky, sometimes being as large 

 as a crow's, are placed at moderate heights, usually from eight to twelve feet; 

 and are, habitually, so well made that they may be lifted clean of their setting 

 without injury. The jays evidently have assigned beats, or ranges, of mutual 

 adjustment, and they are very loyal to a chosen locality at nesting time. Thus, 

 the nests of succeeding years are grouped in a single tree, or scattered narrowly 

 in a small section of the scrub. 



He says that the nest is 'a bulky niasb of interiaced twigs oi Uve oak 

 tree, into which is set neatly and deeply a cup of coiled rootlets with 

 some admixture of grasses and, rarely, horsehair." 



Eggs. — Three or four eggs, rarely five, constitute the full set for this 

 jay. They vary in shape from rounded-ovate nearly to elliptical-ovate 

 but are mostly ovate, with only a slight gloss. They do not show the 

 wide variation in colors exhibited in the eggs of the California jay. 



Mr. Dawson (1923) remarks on this subject: "It is in the uniform 

 coloring of the egg that the Santa Cruz Island Jay most surely reveals 

 its isolation, and its consequent inbreeding. The ground color of fresh 

 eggs is a beautiful light bluish-green (microcline green), and this is 

 lightly spotted with olive (Lincoln green to deep grape green). The 

 green element fades quickly, however, so that eggs advanced in incuba- 

 tion are of a pale Niagara green color. Among a dozen sets there are 

 no color variants worth mentioning; nor have I seen a single example 

 of the 'red' type, which is so pleasing a feature of the mainland form." 



Dawson's colored plate shows some variation in the size and shape of 

 the markings, in pale olives and light browns; some are finely sprinkled 

 with faint dots, others more clearly marked with small spots, and one 

 has pale olive-brown blotches of fair size. He gives the average 

 measurements of 140 eggs in the Museum of Comparative Zology at 

 29.0 by 21.3 millimeters; they range in length from 25.4 to 31.7, and in 

 breadth from 19.6 to 22.6 millimeters. 



The measurements that I have collected of 50 eggs average 29.2 by 

 21.6 milliineters ; the eggs showing the four extremes measure 32.0 by 

 21.5, 29.0 by 23.0, 26.2 by 20.6, and 28.5 by 20.5 millimeters. 



Phmvages. — The plumages and molts of the Santa Cruz jay probably 

 follow the same sequence as in the California jay, to which it is so closely 

 related. The juvenal plumage seems to be only slightly different; Ridg- 

 way (1904) describes it as follows: "Pileum, hindneck, auricular and 

 suborbital regions, and sides of chest dull slate color, slightly tinged 

 with dusky blue ; back, scapulars, rump, and smaller wing-coverts dark 



