The Woodhewer Family. 255 
ing in their bands scores of widely different species, 
and in size ranging from those no larger than a 
wren to others as big as a magpie. It is certainly 
very advantageous to them. As Belt remarks, they 
play into each other’s hands; for waile the larger 
creepers explore the trunks of big trees, others run 
over the branches and cling to the lesser twigs, so 
that every tree in their route, from its roots to the 
topmost foliage, is thoroughly examined, and every 
spider and caterpillar taken, while the winged 
insects, driven from their lurking-places, are seized 
where they settle, or caught flying by the tyrant 
birds. | 
I have observed the wandering bands only in 
Patagonia, where they are on a very small scale 
compared with those of the tropical forests. In the 
Patagonia thickets the small tit-like creeper, Laptas- 
thenura, is the prime mover; and after a consider- 
able number of these have gathered, creepers of 
other species and genera unite with them, and 
finally the band, as it moves through the thickets, 
draws to itself other kinds—flycatchers, finches, 
&c.—many of the birds running or hopping on the 
ground to search for insects in the loose soil or 
under dead leaves, while others explore the thorny 
bushes. My observations of these small bands lead 
me to believe that everywhere in South America 
the Dendrocolaptide are the first in combining to 
act in concert, and that the birds of other families 
follow their march and associate with them, know- 
ing from experience that a rich harvest may be 
thus reaped. In the same way birds of various 
kinds follow the movements of a column of hunting 
