WHITE-FACED IBIS 119 
a much larger number. It is most interesting to 
watch them at such times, now soaring high in the 
air, displaying the deep chestnut hue of their breasts, 
then descending with a graceful curve towards the 
earth, as if to exhibit the dark metallic green and 
purple reflections of their upper plumage. The flock 
is meanwhile continually changing its form or dis- 
position, as if at the signal of a leader. One moment 
it spreads out in a long straight line; suddenly the 
birds scatter in disorder, or throw themselves together 
like a cloud of Starlings; as suddenly they re-form 
to continue their journey in the figure of a phalanx, 
half-moon, or triangle. The fanciful notion can 
scarcely fail to suggest itself to the spectator that 
the birds go through these unnecessary evolutions 
intelligently in order to attain a greater proficiency 
in them by practice, or, perhaps, merely to make a 
display of their aerial accomplishments. The Glossy 
Ibis has another remarkable habit when on the wing. 
At times the flock appears as if suddenly seized with 
frenzy or panic, every bird rushing wildly away from 
its fellows, and descending with a violent zig-zag 
flight ; in a few moments the mad fit leaves them, 
they rise again, reassemble in the air, and resume 
their journey. 
