222 



Owen, A Family of Nestlings. 



TAuk 

 Ljuly 



youngster strove to poise himself and lift his heavy head for the 

 expected morsel, only to collapse, ignominiously, into a panting 

 heap. 



We had provided the camp with a balance, sensitive to one- 

 tenth of a gram, and conveniences for weighing in the shape of 

 sundry pill-boxes for confining the birds. To this apparatus we 

 bore our infant of the teaspoon and found that he tipped the 

 scale-pan at two and nine-tenths grams, or a little more than a 

 a tenth of an ounce. A cautious dab of carmine on the back 

 would serve, we thought, by its bright hue, to distinguish our sub- 

 ject from his mates, and with this decoration we restored him to 

 the nest. The next day we made discoveries that led us to modify 

 our procedure. We found that, by chance, we had selected 

 and marked for experiment the smallest bird in the brood, the 

 runt, in brief, — the last bird, probably, to hatch. Moreover, the 

 carmine had not proved an unqualified success, since the friction 

 of the old birds' feathers and the scrubbing together of the young 

 birds in their cramped quarters had nearly erased the generous 

 daub originally bestowed. Apprehensive lest we might, some day, 

 be unable to recognize the chosen bird, and desirous, also, of get- 

 ting a better idea of development than the smallest bird might be 

 expected to show, we decided to weigh the whole brood, at 12.30 

 p. m., daily, and take the average as the basis of our calculations 

 and inferences. This system was put into practice at once and 

 continued for six clays, all the birds being weighed and a separate 

 record being kept of the marked bird which, as it proved, we 

 were always able to distinguish. The result may be tabulated as 

 follows : 



