GRAY-HEADED JUNCO HH 



and duration of her absences from the nest and of her periods of attentiveness to 

 incubation depend on time of day and weather conditions. During morning 

 hours when the sun's illumination is at its peak due to slope and nest exposure, 

 she tends to keep the eggs or young covered to prevent overheating. She tends 

 to incubate longer and more continuously during raw, wet weather. 



The eggs in a clutch seldom hatch simultaneously. Most hatch in the morning, 

 but often one or two hatch in the morning and the remainder in the afternoon, or 

 even the next day. After the first eggs hatch the female seems to move the 

 others so that they receive optimal warmth. The actual emergence of the young 

 from the egg is very rapid, often helped by the female pulling the shell with her 

 beak. As soon as the fledgling is free, the female eats the egg shell. 



Both male and female feed the hatchlings a diet that appears to be entirely of 

 insects. When the female is brooding, the male sometimes deposits food at the 

 edge of the nest where the female can take it for herself, or give it to the young. 

 The female is very attentive to nest sanitation. At each feeding visit she scours 

 tlie nest and removes the fecal sacs, usually depositing them on the limb of a 

 nearby spruce or lodgepole. The young are apparently not fed in sequence; the 

 same bird may be fed several times in succession if it proves the most aggressive. 

 The nestlings' bright red mouth linings combined with their wide yellow bills 

 give the feeding adult a large, easily visible target. 



The young spend approximately 10 to 11 days in the nest after hatching, 

 though one brood remained 13 days. The nestlings' eyes become slit-like on the 

 fourth day, and open fully by the sixth day. As they become older (7 to 10 days) 

 they venture out of the nest to receive food from their parents, sometimes as far 

 as two feet, always returning immediately to the nest. They also leave the nest 

 temporarily to try out their wings. 



It was thought the nestlings would make their final move out of the nest in 

 response to the parents' enticing them with food, but they sometimes desert it of 

 their own accord when the parents are not present. Not all leave the nest at 

 once; one or two may remain several hours after their more venturesome siblings 

 have gone. Once out of the nest they become very diflTicult to follow. They 

 spend at least three or four days hopping around on the ground before they can 

 fly with any degree of coordination. During this time their parents watch them 

 solicitously from nearby trees and bushes, flying down to feed them occasionally. 



The following history of the young in a nest of dorsalis at Flagstaff, 

 Ariz., is from unpubHshed notes by A. R. PhilHps at the Museum of 

 Northern Arizona. The nest containing four eggs was discovered 

 May 25, 1936 under a tussock of grass, opening toward the west, 

 which was shaded in the morning. The next day at 2 p.m. it contained 

 four young "mostly naked with some gray down on head and rear 

 end." May 29, at 3 days, the four young weighed 27.5 grams. May 

 30— "still nearly naked, eyes not open"; weight 35.5 grams. May 

 31— eyes still closed; weight 44.5 grams. June 1— eyes opening; 

 weight 48 grams. June 2 (8:24 a.m.)— eyes open; feathers of belly 

 tracts becoming prominent; weight 60.5 grams. June 3 (8:15 a.m.) — 

 "One young squealed (first sign of fear instinct) and both parents came 

 to the nest"; weight 62 grams. June 4 (11:40 a.m.)— weight 64 

 grams. June 5 (11:12 a.m.) — v/eight 70 grams; (1:25 p.m.)— only 



