NOTE
The following are the experiments referred to on page 181:—
On the 14th May 1915, a nest of Blackbirds approximately four days old was removed at 6.45 a.m. The temperature was considerably below the normal, and snow lay on all the high ground in the neighbourhood. In a short time the birds collapsed, and at 9.15 a.m. were dead. On the 29th May, at 6 a.m., a second nest was removed, containing young of approximately the same age, and although the conditions were more normal, the temperature being 50° F., the birds collapsed at 8 a.m., and an hour later one of the brood showed little signs of life. The wind, however, then changed to the west, and the temperature rose one degree, with the result that they were still living at 11 a.m. A further experiment was made with Song-Thrushes on the 5th June. The wind was in the south and the temperature 63° F. The young, approximately four days old, were removed at 7.25 a.m., but as they showed no signs of collapse at 1 p.m. I replaced the nest in the original site.
On the 30th May, a nest of Whitethroats three days old was removed at 7.15 a.m. The wind was northerly and the weather fine, but the temperature low—50° F. At 8.15 a.m. the birds showed no sign of life. A second experiment with this species was made on the 10th June under more favourable circumstances, for although the sky was overcast and the wind northerly, the temperature was 59° F. In this case the young survived from 6.55 a.m. to 7 p.m.
On the 27th May 1915, a nest of Hedge-Sparrows hatched the previous day was removed at 7 a.m. The temperature was below the normal, being 49° F. At
