1616 U.S. NATIONAL MUSEUM BULLETIN 237 pakt 3 



Eggs. — The Lapland longspur usually lays five eggs although in 

 my experience the mean number is somewhat less. In 44 nests I 

 studied at Cape Thompson in 1960 the average clutch size was 4.7. 

 Although slightly more than 50 percent were 5-egg clutches the number 

 of eggs laid ranged from 1 to 6. The clutch of one egg, and another 

 of only two, were dutifully incubated and apparently were not the 

 result of eggs having been lost. In 1961 the average clutch size 

 was 4.9 eggs in 64 nests, and the range was from 2 to 6; slightly 

 more than 60 percent were 5-egg clutches. Herbert Brandt (1943) 

 studied 28 nests at Hooper Bay and found an average clutch size 

 of 5.5 with 16 nests containing 6 eggs and 12 containing 5 eggs. 



It seems likely that had Brandt observed a larger number of nests 

 this mean number would not have been so much higher (nearly one 

 egg) than the average per clutch at Cape Thompson. Clutches of 

 three or fewer eggs generally represent renesting attempts and per- 

 haps should not be included in these computations. They do not 

 necessarily represent late nestings, and no evidence was obtained 

 to indicate that clutch size declined as the season advanced. True 

 second nestings are apparently nonexistent, renesting is uncommon, 

 and such variation as exists in number of eggs relates only to the single 

 clutch laid by each female at very nearly the same time during 

 the nesting period. 



The shape, color, and size of the eggs are extremely variable as 

 the following descriptions will indicate. The shape is ovate tending 

 to elongate, to ovate and the surface is slightly glossy. The ground 

 color is pale greenish-white, but on most eggs it appears to be "bufTy 

 brown" owing to the confluence of spots, blotches, and cloudings of 

 "Hay's brown," "Saccardo's umber," "bister," or "mummy brown." 

 This is not to imply a blotchy appearance, as generally the back- 

 ground color tends toward uniformity. Most eggs have scattered 

 spots or scrawls of black. Undermarkings when visible are "light 

 mouse gray," and occasionally this is the predominant color of the 

 egg, with only a few spots or scrawls of dark brown or black. The 

 markings are fairly evenly distributed over the entire surface. 



Gabrielson and Lincoln (1959) describe the eggs as "light greenish- 

 gray, heavily marked with shades of brown." 



Joseph Grinnell (1900) describes a clutch of eggs as nearly oblong- 

 ovate in shape with a ground color, disclosed only at the ends of 

 the eggs, as very pale blue. He states further that "Otherwise the 

 eggs are so completely covered with pigment as to be almost uniform 

 isabella-color. Overlying this are scattered scrawls and dots of 

 bistre." 



Nelson (1887) described the ground color of the eggs as light clay 

 with a pale greenish tinge. He found eggs covered with a coarse 



