With few trees on the horizon, Kazakhstan's steppe rolls out for thousands of square kilometres, scorched to 40°C in summer and frozen to -40°C in winter, the silence broken only by wind moving through the grass. Underground, colonies of ground squirrels and marmots dig and forage, hidden from what's circling above them. 

With a wingspan approaching 2.6 metres, the Steppe Eagle rules this open sky. With very few trees to nest in, it builds directly on the ground, or on a rocky outcrop, laying its eggs in full view of a horizon that stretches in every direction. When ground squirrels are scarce, this hunter becomes a scavenger, tearing into the carcass of a Saiga Antelope left out on the open plain. 

As autumn arrives, the eagle that ruled this landscape all summer simply leaves it behind. It flies over 10,000km, crossing deserts and mountain ranges, to land somewhere entirely different – an African savannah alive with swarming termites, or a rubbish dump on the edge of a Middle Eastern or Indian city. Here, the fierce hunter of the steppe becomes something else; a slow, opportunistic scavenger, waiting out the winter before the long flight home. 

Not so long ago the Steppe Eagle was the most abundant large eagle on the planet, a familiar shape circling over grassland from Eastern Europe to East Asia.  

Now, that same silhouette is disappearing, its numbers have more than halved in recent decades, and danger waits at every stage of its 10,000km migration.