472 Changes of Habit among Woodpeckers. [ August, 
blers, even, we have in Iowa the black and white creeper (Mnio- 
tilta varia), that excels most woodpeckers in ability to scramble 
over and thoroughly search the bark of a tree. The whole 
family of creepers, the Certhias, — represented with us by the 
little brown creeper, (Certhia familiaris), — is also able to com- 
pete successfully with woodpeckers on their own ground. But 
perhaps the most expert of all the perchers that have taken to 
clambering over trees are the nut-hatches. A very common one 
is the Sitta Carolinensis, which may be seen almost any day on 
trees in our streets and door-yards. Its nervous and rapid move- 
ments, its slaty-colored back, and black crown must be familiar 
to all. It moves upward and downward with equal facility and — 
always head foremost; the upper and under side of a limb are 
explored with equal ease; rarely resting, it frisks up and down, 
round and round, over and under, in and out, finishing a tree and 
ready for the next long before the average woodpecker would be 
able to collect himself and get fairly under way. 
_ The habit of climbing is certainly an ancient one among wood- 
peckers. All the genera have the feet, tongue, bill, tail feathers, 
etc., modified in substantially the same way, and this would point 
to an ancestor that practiced their characteristic habits before 
the modern genera began to diverge. On the other hand, we 
may fairly conclude that since climbing is rather exceptional 
among perchers, the few groups that practice it have acquired it 
at a comparatively recent date, and it is quite possible that com- 
petition with climbing perchers may constitute a large share of 
the disturbing cause which has compelled certain woodpeckers 
of late to abandon the habits of their ancestors. 
It is worthy of note, too, that the species which have suffered 
most in this competition are among the largest of our Northern 
woodpeckers. With the exception of the pileated woodpecker, 
they are in fact the largest, and furnish another illustration of 
the fact that nature looks with but small favor upon mere bulk. 
A little nerve often outweighs a large amount of muscle. 
The pileated woodpecker frequents deep forests, and I have 
never been able to observe its habits. Its retirement, howeve?, 
has withdrawn it from competition with the more agile forms we 
have noticed, and if food is only sufficiently abundant there is no 
immediate necessity for giving up its ancestral habits. The red- 
head and flicker, preferring open glades, are brought into Con- 
_ stant and active competition with more sprightly and energetl¢ 
climbers, and find themselves obliged to adopt other habits m 
great measure, or perish. 
