McCOWN'S LONGSPUR 1581 



inch as measured by Brown (Roberts, 1932) of 11 sets in Minnesota. 

 The 72 eggs Mickey (1943) recorded in Wyoming averaged .8089 by 

 .6086 inch. Harris gives the average measurements of 100 eggs as 

 20.4 by 15.0 millimeters, with eggs showing the four extremes measur- 

 ing 22.9 by 15.9, 18.8 by 14.6 and 19.8 by 13.7 millimeters. 



Egg size and weight within a clutch may vary somewhat, according 

 to Mickey (1943). At one nest she found that "one large egg was 

 deposited the first day, followed on the second and third days by 

 lighter, smaller eggs." Concerning the egg weight Mickey (1943) 

 writes: "Fresh eggs varied in weight from 2.3 to 2.5 grams; the 

 average of six was 2.4. Eggs weighed the day before hatching varied 

 from 1.7 to 2.15 grams; the average of seven was 1.914 grams. * * * 

 The average total weight of a three-egg set was 7.21 grams as compared 

 to 9.5 for a four-egg set and to 11.4 for the one five-egg set weighed." 



There seems to be some geographical variation in the ground 

 color of the eggs. Raine (1892) found that in the eggs near Rush 

 Lake in Sasketchewan "the ground colour varies from white to greyish 

 white, pinky white, clay and greyish olive, usually boldly spotted 

 with umber and blackish brown; many of the eggs are clouded over 

 with dark purple grey which almost conceals the ground colour, and 

 many of the eggs have scratches and hair-like streaks of brown." 

 The ground color of the eggs in the Brown (Roberts, 1932) collection 

 from Minnesota is a "pale greenish-white of varying intensity, more 

 or less obscured in three of the eleven sets by a buffy tinge." In 

 Wyoming Mickey (1943) discovered that "The ground color * * * 

 varied from white to pale olive. The markings consisted of various 

 combinations of lines, scrawls, spots, and speckles of lilac, rusty- 

 brown, mahogany, and in one case black." In general, Harris writes 

 that "the ground may be grayish white or a very pale green such as 

 'tea green.' There is considerable variation in coloring and pattern." 

 Raine (1892) found one set near Rush Lake in Saskatchewan which 

 "is remarkable in having all the markings at the larger end of the egg 

 where they form a zone." 



The earliest date for full clutches of eggs is May 9 in a listing by 

 DuBois (1935) for Montana, the latest being July 28. In the same 

 state near Lewistown, Silloway (1903) reports a nest of three fresh 

 eggs on May 29. In Wyoming, McCreary (1937) quotes Neilson as 

 finding "full sets of 4 eggs near Wheatland by May 20." Near 

 Laramie, Mickey (1943) came upon a nest with one egg on May 20 

 and a full complement of four on May 25. She reports the latest date 

 for a full clutch as August 6. In Saskatchewan, Raine (1892) "flushed 

 a McCown's longspur from its nest and five eggs" on June 10, 1891. 

 Brown (Roberts, 1932) collected "five sets of eggs, all nearly fresh" 

 in early June 1891 in Minnesota. 



