416 THE ZOOLOGIST. 



many of the young birds, recognizable by their yellow plumage 

 and immature call-note, leave the place of their birth altogether, 

 wandering leisurely southwards. 



Judging from the systematic observation of the last two 

 years in this wood, it would appear that the local proportion of 

 Willow-Wrens having second broods is about fifteen to twenty 

 per cent. In 1910 there were four second nests, from three of 

 which broods were reared, one having the eggs destroyed. (These 

 nests belonged to pairs Nos. 4, 18, 19, 22 ; they are indicated in 

 the map thus a .) The intervals between the fledging of the first 

 broods and the commencement of laying for the second clutch 

 were, in three of the cases, approximately ten, fifteen, and eight 

 days respectively ; the sites being seventeen, twenty, and fifty- 

 five yards distant from the first nests. As already stated, the 

 food of the second broods, both while in the nest and after 

 leaving it, consists chiefly of Diptera in the mature form — a 

 decided contrast to that of the first broods. Another point of 

 distinction is that the males frequently take no share whatever 

 in the feeding of these late families. This was the case in all 

 three second broods reared in 1910, although in each instance 

 the males had taken their share with the earlier families. The 

 explanation appeared to be that they had by that date (late July) 

 already departed from the locality, leaving their more dutiful 

 mates to their own resources. In the previous season, however, 

 when the broods were a week earlier, the males in some cases 

 assisted in their rearing, so that there is no invariable rule in 

 the matter. The rate of feeding is decidedly more rapid with 

 these second broods. Thus while first broods, when nearly 

 fledged, are fed (by both parents) from fifteen to thirty times in 

 the hour, second broods at the same stage of development — even 

 when tended by the female alone — are fed at the rate of thirty- 

 five to fifty times per hour. One bird was observed to feed her 

 young seventy times in that period — an astonishing performance, 

 the more so that it took place in an exposed locality during half 

 a gale of wind. This increased activity is no doubt chiefly due 

 to the greater abundance of food in late July, but the desire of 

 the birds to set out on their southward journey is probably a 

 contributory cause, making them restless and eager in their work. 



The vocabulary of Willow-Wrens is an unusually limited one. 



