Observations on the Cuckoo. 461 
in attempting to accommodate herself to eggs 
of different sizes. If comparatively large 
and small eggs are placed in the same nest, 
some of the smaller ones are generally thrown 
out, or rendered addle, by the hen bird, in 
endeavouring to arrange them so that she 
may distribute nearly an equal degree of 
warmth and pressure to all; but the larger 
ones, which chiefly sustain her weight, and, 
consequently, are less liable to be moved, 
usually remain unmolested. When the eggs 
of birds are exchanged for others of a uniform 
magnitude, whether larger or smaller than 
their own, provided the difference is not so 
great as to occasion them to be forsaken, no 
disturbance ensues, whatever their colour may 
be, the change either not being perceived, or 
totally disregarded ; and the young when ex- 
truded, are attended with the utmost care and 
solicitude. 
Cuckoos generally use the precaution of 
waiting for the absence of small birds from 
their nests before they venture to lay in them: 
sometimes, however, their approach is per- 
ceived, when the owners immediately make 
every effort to repel them, but do not always 
succeed, as the following instance evinces. 
On the evening of the 24th of June, 1814, I 
saw a hen cuckoo alight in a field of mowing 
