Bird lore - Project Puffin

The Audubon Societies 193
to build a nesl in April, as an illustration of the sequence of plumages and
molts. The adult Robins are in perfect nuptial plumage. They are about to
build a nest, and to rear a brood of nestlings whose juvoml plumage, after the
natal down is shed, will look very different from that of their parents. A second
and sometimes a third brood may be hatched and reared, so that during the
summer, by watching this single family, in two or three divisions, as the case may
be, you can see Robins in all stages oijuvenal and nuptial plumage. Before the
regular migration south, there is a time when many birds are molting. It is a
silent time, for birds sing little if any when changing their plumage. Fortu-
nately for them. Nature has provided that they shed their feathers a few at
a time and not too many at a time on any one part of the body or irregularly
on the two sides, so that usually flight is not interfered with. Ducks are an
exception, but the history of their changes of plumage is a story by itself.
Postnuptial means after the bridal or mating season, as you see, and since our
family of Robins is made up of both old and young, we shall be able to observe
the postjuvenal molt of the young and the postnuptial molt of the parents dur-
ing the early fall. Since the long migration journeys must expose a bird to unusual
wear and tear of plumage, it is evidently advantageous to have new
clothes before starting on these perilous trips. As a rule, birds molt before
migrating, but again some exceptions occur. Through the winter, we have so
few Robins venturing to brave the northern latitudes, that we may scarcely
expect to see any before March. Our Robins in spring are wearing after the pre-
nuptial and postjuvenal molt of the preceding fall, a ^'Jirst winter'' and nuptial
garb, according to their age. It is very instructive to compare the nuptial
plumage of the adult Robins with the "first winter" plumage of the young ones.
All pair and nest, and by the next fall, having molted, no further difiference in
plumage is noticed, except in the nestlings of the season, which of course re-
semble the nestlings with which we started the preceding season.
We have already taken up briefly the most strikingly marked and colored
kinds of feathers, but we have not considered the differences in color and mark-
ings of old and young birds, or of male and female birds. The reasons for the
great variation in color and markings, not only of birds but of many other
animals as well as plants, are far too complicated for our present study. We will
simply learn that these variations occur and that we must, therefore, study the
plumage of young and old birds as well as of male and female birds separately.
In many cases, the two sexes seem to be nearly or quite alike, as for example,
the Blue Jay, Crow, Robin, and Crackle, although the young of some of these
species may differ markedly from the adults. In other cases, one would hardly
recognize a male and female as belonging to the same species if only the color
of the plumage was considered. The Red-winged Blackbird, American Cold-
finch, Towhee, Scarlet Tanager, and Baltimore Oriole are familiar examples.
By observing the size, shape, bill, manner of flight, and habits, one can see the
relation of the two sexes, but it takes careful study on the part of a beginner.