824 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



a fecal sac, and I found several discarded ones on the feeding grounds. 



Nice's (1943) observation that devotion of parent passerines to 

 their young typically increases as they grow was exemplified by several 

 incidents. A banded female who lost her mate early in incubation 

 successfully hatched her three eggs, but deserted the young on their 

 second day. A male whose mate disappeared when their four young 

 were 6 days old continued to care for them until they fledged. The 

 death of one of these nestlings on the eighth day and the fouling of 

 the nest with excreta by the ninth day suggest he had difl&culties 

 carrying on the parental duties alone. 



At another nest I visited daily from the time of hatching until the 

 young fledged, the parents never performed the distraction display 

 until the last day. As I Ufted the 9-day-old young from the nest 

 to weigh them they gave the distress call. This brought the parents 

 from the feeding grounds 60 yards away. They ran around on the 

 ground within 10 feet of me uttering the tsip notes and fluttering 

 their wings. Several times they flew within a few feet of me buzzing 

 their wings audibly. Although well aware of its purpose, I still 

 found their display distracting. 



The LavaUette nestUngs were weighed and measured daily. 

 During their first 7 days of nest life they increased in weight from 2.1 

 to 13.7 grams, or 1.6 grams per day. The remaining 3 days showed 

 an average gain of only 1.5 grams to 15.2 grams. The rectrices and 

 remiges began growing rapidly on the third day and averaged 4.5 and 

 17.5 millimeters respectively on the ninth. The tarsi, which measured 

 7.0 miUimeters at hatching, were over 22 millimeters, or essentially 

 adult length, when the young left the nest. As running is their only 

 means of locomotion for several more days, it is not surprising that 

 their tarsi mature so quickly. 



Comparable weights and measurements were made on 14 adult 

 males and 3 females taken at Chadwick between May 6 and June 27, 

 1955, as follows: Weight, males 24.2 grams (21.9-27.4), females 

 22.3 grams (19.8-24.4); wing (chord), males 64.2 millimeters (60-66), 

 females 58.3 millimeters (58-59); tail, males 55.3 millimeters (54-59), 

 females 51.0 millimeters (49-53); tarsus, males 23.0 millimeters 

 (22-25), females 22.2 milUmeters (21-23). 



Plumages. — The color of the plumages of the seaside sparrows 

 matches their natural surroundings. The olive-gray upperparts of 

 the adults resemble the color of the mud on which they forage. The 

 browner streaked plumage of the juveniles, which shows a striking 

 resemblance to that of the sharp-tailed sparrow, doubtless hides 

 them more effectively in the dense grass where they spend most of 

 their time. 



