414 THE ZOOLOGIST. 



near the nests, only chasing the females playfully when the 

 latter are on their short feeding-excursions. 



The hens sit very constantly, only leaving their nests for a 

 few minutes in search of food at various times of the day, but 

 apparently chiefly in early morning and again about sunset. 

 Incubation lasts twelve to thirteen days, the young spending 

 thirteen to fourteen in the nest. These are average periods ; 

 here again there are differences, sometimes puzzling, between 

 neighbouring nests — in one case, nearly fifteen days were required 

 for incubation. The shortest time spent in the nest by broods 

 is twelve days, but thirteen or fourteen is more common. If 

 disturbed, they are able to flutter out when only nine or ten days 

 old. When the young are still only a day or two old much time 

 is spent brooding them, the female feeding them once or twice, 

 and then covering them for a considerable interval before going 

 off for a fresh supply of food. These intervals of brooding 

 decrease in extent day by day, and cease finally when the young 

 are about eight days old. At this stage, too, the female no 

 longer broods them by night, and roosts elsewhere ; but this 

 may be merely a question of room — six or seven nearly fledged 

 Willow-Wrens in a nest are a lesson in tight packing ! With the 

 hatching of the young the male normally enters on his fourth 

 stage. He takes, as a rule, a fair share in the rearing of the 

 family, and less time is consequently passed in the " song-centre." 

 The song, however, continues practically unabated, being re- 

 peatedly uttered while the bird's bill is full of caterpillars. Some 

 males commence to assist their mates as soon as the young are 

 hatched ; others ignore the latter for some days. In one case 

 the male only tardily realized his duties when the young were 

 nine days old. The following notes, referring to nest No. 8, 

 when the young were three days old, may be taken as typical of 

 that stage ; here the male had not yet taken any notice of the 

 young birds, though he did so a little later on : — 



"June 16th, 11.50 to 12.50 p.m. :— 11.50, female on nest; 

 11.55, female left nest; fed young 11.58, 12.0, 12.10, and then 

 brooded until 12.20; fed young again 12.23, 12.26, 12.29, 12.32, 

 12.36, and then brooded until 12.45 ; had not returned by 12.50. 

 Thus in the hour she fed the young eight times, and brooded 

 them for intervals of ten and nine minutes." 



