826 On the Acceptance or Rejection of Insects by Birds. 
fore took it out and threw it into the Blue-Robin aviary ; the 
cock bird immediately flew down, seized it, and was so much 
pleased w 7 ith its flavour that, although the hen begged for it, 
he would not give it up, but devoured it himself. The 
young birds w r ere hatched during the first week of July, but 
only one w^as eventually reared; this nestling was almost 
entirely fed upon flies, spiders, large and small (including 
numerous full-grown females of Tegenaria atrica , one of the 
most repulsive-looking of our British species) , white butterflies, 
numerous examples of Pterostichus madidus , moths (including 
Agrotis saucia and Zeuzera cesculi ), mealworms and small 
earthworms : the only moth I was doubtful about w 7 as the 
wood-leopard ( Zeuzera cesculi) ; the old birds ate several 
specimens, but I did not see them disgorge them for the 
benefit of the young. 
On the 16th August I obtained a full-grown caterpillar of 
Cerura vinula , a specimen of which, it will be remembered, 
was greedily eaten some years ago by my Nightingales. I 
turned it into the Blue-Robin aviary, and the hen flew 7 down, 
seized it in the middle, and carried it to the ground, then 
started back suddenly as if stung (possibly the larva had 
ejected acid into her mouth or eyes) ; she then examined it 
curiously, pecked at it cautiously, springing back after each 
peck, and finally flew aw T ay. The cock and young bird now 
flew 7 down and examined it, the former pecking it and jumping 
back several times, evidently half afraid of it ; then both flew 
away, and I took it out. It was quite uninjured, so I turned 
it into the next aviary, w 7 hen the Weavers and Nonpareils 
flew down and formed a circle round it ; they walked round 
and round with outstretched necks for two or three minutes, 
the hen Nonpareil alone venturing to peck it once ; then all 
flew aw 7 ay simultaneously. The caterpillar never once put 
itself into what is supposed to be a u terrifying attitude,” but 
crawled like a great gaudily-coloured slug along the ground. 
I now turned it in with the Leiothrix , and they jumped 
round and pecked at it, but found it too tough a morsel; I 
do not think they were a bit afraid of it. I next offered it to 
one of my Blackbirds, but he sidled aw~ay along his perch 
and looked in a contrary direction. Lastly I put the cater- 
pillar into the cage containing a Great Tit, and he flew dowrn 
at once, seized and tore it to pieces, eating it with relish. 
At first sight it w^ould appear that, judging by these 
experiments, the caterpillar of Cerura vinula enjoyed almost 
perfect immunity from destruction ; but when we consider 
that the birds which rejected it were, w r ith the exception of 
the Blackbird, only those which would never come in contact 
