IS NEST-BUILDING AN INSTINCT IN BIRDS ? 275 
the conclusion, from their very quarrelsome habits, that they 
were of the same sex ; in consequence of this opinion, which I 
afterwards found to be erroneous, I asked the lady who gave me 
the first pair to give me another young dove. She gave me 
one brought up in the same manner. I kept these three doves 
in a wire cage until this spring. The exact size of the cage 
was three feet by two, and two feet high. They turned out to 
be a cock and two hens. At the end of February each hen laid 
two eggs on a bundle of hay placed in one corner of the cage ; 
but there was not the slightest attempt at nest-building, al- 
though they played with the hay, carrying about a piece in 
their bills by the hour together. The females sat by turns 
with the male, and in due time three of the eggs hatched. Al- 
though some interesting facts were brought to light in the 
rearing of these young birds, it suffices to observe in the present 
connection, that only one of the young birds became fully fledged, 
the others died from heartless neglect on the part of the parents, 
apparently because they were feeble and two days younger than 
the chick that was reared. 
In the middle of April I turned the three birds out into an 
aviary in the open air, in which there was a large branch of a 
tree with numerous twigs and buds to serve as a perch. The 
highest branchlets' of this were about nine feet from the ground. 
I provided the birds with a double breeding-box, similar to 
the one in which they were themselves hatched, in one side of 
this I placed a handful of hay, together with their newly fledged 
offspring. I left the other side empty, in the expectation that 
they might possibly build a nest of hay or straw, and I supplied 
them with both materials. The young dove learned to fly in a 
few days, and slept in its box at night, its parents and foster- 
mother fed it continually in the nest-box ; but there was no 
attempt to make another nest in the box. 
About a week after I placed the birds in the new aviary they 
took possession of the highest twigs of the tree branch, each with 
a small piece of stick in its bill; as I judged they intended to 
build in this portion of the tree, I at once supplied them with a 
number of twigs; these were nearly all straight twigs of varying 
length and thickness, without any lateral branches; but amongst 
them were a few pieces, each with a short lateral branch, which 
faere at once collected by the doves, and carried to the place 
they had selected for their nest ; but they evidently had not the 
slightest idea of the use of the sticks they had selected. They 
tried in vain to fix them to the wall of the aviary or to its roof, 
almost always to the latter, and waved them about above their 
heads until they dropped them. I thought that they might be in 
the habit, in nature, of laying the foundations of their nest in 
twigs above their heads, so I fixed some perches below the cleft 
