This creates a food chain with four levels:
Use the slider: The plants produce energy and support animal consumers. After each step, only 10% of the energy is left.
Source: Khan Academy
To support enough prey for an eagle, the ecosystem needs half a million calories.
That means every pair of golden eagles needs a huge territory.
So that's the reason I've never seen one: there simply isn't enough food in the ecosystem to support a lot of eagles.
Now let's do a thought experiment.
Imagine you can only eat eagle meat. 80 km2 would only provide 50 calories!
You would have to travel all over the world to get enough calories.
Clearly, eating eagles is not a good survival strategy.
The rock partridge is one of the few birds who stays in the mountains during winter.
In the harsh conditions with little food, it has adjusted to survive with little protein.
Us clever humans used a different trick to deal with food shortages.