PATTERNS OF COLORATION. 613 
[E.] ON THE RELATION BETWEEN LATITUDE AND THE 
PATTERN OF COLORATION IN OHIO BIRDS*. 
At the last meeting of the Society I expressed an opinion somewhat adverse to the 
universal application of the laws of latitudinal variation among birds, at least to their 
availability for the purpose of determining whether certain forms shonld be considered 
species or varieties tT. 
At the same meeting I expressed myself as doubtful of the correctness of the opinion 
there advanced that white wing-bars and white tips to tail feathers should be considered 
as simply ornamental. A few words will give my reason for dissenting from such a view. 
Without attempting to show that tail spots or wing-bars are not peculiar to that sex 
which is most highly ornamented among birds, let us first examine into the structural 
relation of the feathers bearing these marks to the marks themselves. In the case of 
white tail tips, 1am of the opinion that the presence or absence of these spots has 
largely to do with the form of the tail, of which there are two strongly marked types, 
forked and rounded. In the former the lateral feathers are the longest, in the latter the 
central. Among all our Ohio birds, Ifind none with forked tails and white tips to 
the tail feathers, all white tail tips being combined with mere or lessrounded tails. The 
King-bird has a white tipped tail all the tips being nearly equal, while the tail as a 
whole is nearly square. In other birds with a rounded tail and white tips the white in- 
creases in the same orin an increasing proportion to the shortening of the lateral 
feathers. I do not wishit to be understocd that all birds with rounded tails have white- 
tips for this is not the case, but that there is a definite correllation between these 
characters is evident. Inthe Hammingbird, the male has a forked tail of uniform color, 
while the female has a rounded tail with white tips. 
In tail feathers then we find white tips associated with the feathers of less develope- 
ment as to length, and I might add that in many birds the white of the tip extends 
towards the base of the outer feathers along the outer, that is to say the shorter, web of 
the feather. 
In the case of wing-bars the same relation may be seen, though perhaps there are 
more exceptions to the rule than in the case of tail-tips. Wing-bars, that is white tips 
to the greater or lesser row of wing-coverts are in their greatest perfection in Passeres, 
in which order, the coverts are not more than half as long as the secondary quills, while 
in all other orders, with few exceptions (6. g. Picids), the wing-coverts are more than 
half the secondaries. I find a single reason, and this a negative one, to suppose that 
wing-bars may be simply ornamental, as foilows; Most birds in the Order Passeres 
which have wing-bars nest in trees, while in many instances the lack of wing-bars is 
associated with the habit of ground nesting. The relations between this habit and 
the presence or absence of this color-mark are well seen in family Sylvicolide, where, 
with the exception of one or two species of Helminthophaga, all the ground nesting 
* Read before the Columbus Society of Natural History, Aug. 29, 1874. 
t The laws of latitudinal variation have been given on page 194-196 of this report and 
need not be again presented here. 
