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 days, 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 : 
Marked Bird. 
Average of the Brood. 
Date. 
Weight. 
Date. 
Weight. 
' — 1 
- c 
Cn'-vi 
2.9 gms. 
4-5 “ 
July 16. 
“ i7- 
5.80 gms. 
8.62 “ 
“ 17 - 
7 . 2 “ 
“ 18. 
10.91 “ 
“ 18. 
9.0 “ 
“ i9- 
13.68 “ 
“ ! 9 - 
12.6 “ 
“ 20. 
1544 “ 
“ 20. 
14.1 “ 
“ 21. 
16.58 u 
“ 21. 
16.0 “ 
