1582 U.S. NATIONAL MUSEUM BULLETIN 237 paet 3 



Apparently eggs are laid early in the morning. In a nest DuBois 

 (1937a) visited "both morning and evening, they were laid before 

 6:00 or 7:00 a.m." Mickey (1943) writes: 



On July 8, 1939, at 7 a.m. I observed F18 flying about in small circles just 

 above the top of the grass in the vicinity of her nest. When I came into the 

 territory, she flew away. Then her mate flew around me as if he were trying 

 to drive me off; so I walked a short distance away and sat down. About five 

 minutes later the pair returned to the nest site; the female dropped into the grass, 

 the male perched on top of a nearby rabbitbrush. After a while he dropped 

 down and fed. I walked over and flushed the female from her nest, which con- 

 tained one warm egg. 



Incubation. — DuBois (1937a) states that "the eggs are deposited 

 at the rate of one each day" and "incubation begins when the last 

 egg is laid." There seems to be room for latitude here, for Mickey 

 (1943) sees it differently. "It seemed to me that the birds were 

 somewhat erratic in this respect; for I found that the eggs of a com- 

 plement were not always deposited on successive days, nor did the 

 female always wait for the completion of the clutch before starting to 

 incubate." 



Incubation seems to be the duty of the female. DuBois (1937a) 

 writes, "I have never seen a male on the nest before hatching time," 

 and Mickey (1943) concurs: "I did not at any time flush a male from 

 a nest containing eggs." 



Information on the length of the incubation period is confined to 

 the detailed observations of Mickey (1943) who states, "I have data 

 on two pairs that were successful in hatching more than one brood. 

 Nests 3 and 23 were thought to be those of the same pair * * *. The 

 length of the incubation period was twelve days. This was calculated 

 from the laying of the last egg until the time of its hatching, from 

 June 22 to July 4, at nest 3." While the female incubates, "she turns 

 around very often in the nest, and sometimes erects the feathers of 

 her crown," writes DuBois (1923). He adds, "the female sometimes 

 sings at her nest when the male is approaching." 



During this period, writes Mickey, 



the male longspur spent a great deal of time (a) guarding the nest from some 

 nearby rock or shrub, (b) engaging in flight-song, or (c) defending his territory, 

 particulary if nests were close together. 



Sometimes the male was seen guarding the nest during the female's absence; 

 at other times neither bird was near the nest. M4 was never in the vicinit}' of 

 of the nest when the female was absent. M6 was usually on guard from a pile 

 of stones close to the nest, not only while the female was off the nest, but also 

 while she incubated. He often sang from this stone pile. Whenever I came near 

 the nest * * * he either flew about over the nest or circled about in the grass 

 nearby, making some pretense of collecting food. 



* * * 



Male longspurs sang during the incubation period, but with less intensity than 

 prior to mating. 



