Male red deer are starting their rut.
The air is heavy with the scent of females.
The rules are simple, winner takes all.
Across the northern hemisphere , the deciduous forests are changing.
Leaves that have provided food and shelter since the spring, are now shed.
In the broadleaf forests of Russia, winter is particularly severe.
But there will always be some who benefit from hardship.
Black vultures scavenge from the carcass of a seka deer
that has died of cold or starvation.
These endangered birds are visitors,
they've come down from the north to escape the even colder conditions in Siberia.
An Amur leopard, the rarest cat on Earth.
Winter is a difficult time for this hunter.
There are no leaves for cover and no young prey animals.
This female has the added pressure of having to provide for her one-year-old cub.
It will be another 12 months before he'll be able to fend for himself.
The bickering vultures have abandoned the carcass.
It's a valuable discovery for the leopards.
But the cub doesn't share its mother's sense of urgency.
The vultures have left behind plenty of good meat, but it's stiff with frost.
The mother works to open the hide and make feeding a little easier for her cub.
There are only 40 Amur leopards left in the wild
and that number is still falling.
The harshness of the winter here, hinders their increase in numbers.
It takes one of these females longer to raise her young to independence
than it does a leopard in Africa.
If the mother can sustain her cub for a few more weeks,
spring will bring an increase in prey and her task will lighten.
For all the inhabitants of this seasonal forest,
the long, cold wait is nearly over.
Spring in a deciduous woodland is special.
With no leaves overhead, the rays of the sun strike the forest floor directly
and their warmth rouses plants from their winter sleep.