These habits are modified so as to suit cold and heat and the variations of the seasons.
Aristotle’s History of Animals, Book VIII, chapter 12, 350 BCE
1. We account for the absence of certain birds in winter
through a combination of observation and travelers’ reports.
I have seen cranes flying south in the fall,
their bodies the size of kites in the great distance above us
and their horn-like call a musical reminder of our diminishing season.
As wealthy men spend summer in cool places and winter in sunny ones,
cranes summer by the Black Sea and winter in Nile marshes
where they defend their eggs in battle with goat-riding Pygmies
whose spears match in length the cranes’ pointed beaks.
They drench the land in gore
with a ferocity Homer likened to a Trojan battle.
2. Our redstarts of summer disappear in winter
when robins are seen. Note the similarity
in size and coloring: the redstart’s orange belly and undertail,
the slate head and back as if he dons a hooded cloak;
the robin’s markings are muted like winter’s landscape.
We may assume the one transmutes into the other
to live more comfortably in each season.
From these birds we learn the rhythms of time and weather.
3. Storks, kites, and doves fall into winter torpor
like their animal counterparts.
Swallows are nowhere to be found
and, like the redstarts, are too small to journey
from one land to another. Rather,
they sleep the winter through, hidden
in hollow trees or submerged in marsh-mud,
as men seek shelter in houses in winter.
Although fishermen may dredge hibernating swallows
from the depths, the birds will soon die
if awakened before their time.
Left to natural desire
in spring their beaks forge up through the silt
which flows off the birds as they float to the surface
and leap joyfully into the sky where they dip and dart
in the exuberance of spirits that all animals
display when once again sun warms the blood
and the season of growth stirs all creatures
to their natural cycles. Only we who observe them
count the years to their inevitable end.