76 LIFB HISTORIES OF NORTH AMERICAN BIRDS. 



s})ruce, and tamarack trees, and varied from 4 to 15 feet above the water. A 

 fortnight hiter (June 15) 1 found a nest of Picoides ardicus, containing- young 

 (apparently about a week old), at West Pond, near Big Moose Lake. It was in 

 a tamarack tree and about 10 feet above the ground. A last year's nest in an 

 adjacent tamarack was occupied by a family of living squirrels."* 



I first met with the Arctic Three-toed Wood])ecker on the sunnnit of the 

 Blue Mountains, near Soda Springs, Grant County, Oregon, in August, 1876, at 

 an altitude of about 5,500 feet, where it was rare, and again near Fort Klamath, 

 during the year 1 882-83. There they were faii'ly common in winter, frequenting 

 the more open pine forests in the mountain valleys, but were rarely seen by me 

 in summer, and I believe they mostly retired to an extensive burnt tract, some 

 30 miles to the northeast of the post, near the head waters of the Deschutes 

 River, to breed. Like the Hairy Woodpecker, they are persistent drummers, 

 rattling away for minutes at a time on some dead limb, and are especially active 

 during tlie mating season, in April. I have located more than one specimen bv 

 traveling in the direction of the sound when it was fully half a mile away. On 

 May 10, 1883, while en route from Fort Klamath to Linkville, Oregon, and 

 only a feAV miles from the latter place, just where the pine timber ended and 

 the sagebrush commenced, I found a male busily at work on a pine stum]), 

 only about 2^ feet high and about 18 inches in diameter, standing within a few 

 feet of the road, and close to a charcoal burner's camp, in quite an open and 

 exposed situation, nearly all the timlier in the vicinity having been cut down. 

 The stump was solid, full of pitch, and showed no signs of decay; the entrance 

 hole was about li inches in diameter and 8 inches from the top. The cavity, 

 wlien first examined, was only about 2 inches deep, and on my return, two days 

 later, it had reached a depth of 4 inches; the female was then at work. To 

 make sure of a full set of eggs, I waited luitil the 25th. The cavity tlien was 

 found to be 18 inches deep, and was gradually enlarged toward the bottom. The 

 four eggs it contained had been incubated about four days. The female was on 

 the nest, and uttered a hissing sound as she left it, and might easily have been 

 caught, as she remained in the hole until the stump was struck with a hatchet. 

 The sides of the cavity were quite smooth, and the eggs were partly embedded 

 in a slight layer of pine chips. The locality where this nest was found was near 

 the top of a low divide, not over 4,100 feet in altitude. The majority of nesting 

 sites seem to be located in dead trees or stumps, and rarely at any great height 

 varying usually from 2 J to 8 feet from the ground. 



Both sexes assist in nidification, which is usuallv at its heig-ht between Mav 

 20 and June 10, as well as in incubation, which lasts about two weeks. Only one 

 brood is raised in a season. The eggs are generally four in number. These are 

 mostly ovate in shape. The shell is fine-grained and only moderately glossy, 

 and, like the eggs of all Woodpeckers, pure white in color. 



The average measurement of thirteen eggs in the United States National 

 Museum collection is 24.38 by 18.29 millimetres, or 0.96 by 0.72 inch. The 

 largest egg measures 25.40 by 19.56 millimetres, or 1.00 by 0.77 inch; the 

 smallest, 22.35 by 17.53 nnllimetres, or 0.88 by 0.69 inch. 



