Friday, February 18, 2011

Of Eagles, Rabbits and Partidges

It is quite remarkable how we often observe the world around us without fully appreciating the depth of time that we are observing. Three species are currently staging a "cat-and-mouse" saga that goes back to the Pleistocene. The game is at least 100 thousand years old!

The "cat" in our game is the majestic Spanish Imperial Eagle, an endangered species which is endemic to the Iberian Peninsula. I watched these birds hunting in the plains of La Janda this week.

There are two "mice" in this story. One is a bird - the Red-legged Partridge (above). The other is a mammal - the Rabbit (below). Both are Iberian endemics too. Hard to believe it may be but the Rabbit evolved within the Iberian Peninsula and has been introduced everywhere else by humans!

The eagle is one among a suite of species (including the endemic Iberian Lynx) that have relied to a large degree on these two prey species. Both reproduce quickly and in large numbers and have been an almost inexhaustible supply of food for these predators.

Rabbits are doing particularly well in La Janda, having recovered from epidemics that have reduced their numbers in recent decades. It is wonderful to see families of them sunning themselves close to their burrows under the cover of wild olives (above). Indeed a millennial sight! Rabbits must have been so numerous that they gave Spain its name. The Roman Hispania was derived from the Carthaginian Ispania which is thought to come from the word Sphan which meant Rabbit. Literally Spain means "Land of Rabbits"!

With the big eagles lurking Rabbits rely on camouflage and keeping still (above) to go by unnoticed. Partridges too are cryptic when seen from above or behind (below).

But Nature generates uncontrollable impulses which can expose prey. Partridges calling out to stake out territories may suddenly become visible (below).

...and the eagles are ready to pounce!

their strategy is to dive from great heights (above) or to approach low with stealth (below)

either way it is a long, tried and tested, method with great rewards...

Above: Spanish Imperial Eagle with Rabbit

It's hard to fathom, watching in awe as these animals play out this game of life an death, that the same sight was seen millennia ago by our Neanderthal cousins. They died out and we have put the eagle's future very much on the balance. How much longer will we allow this millennial game to continue to be played in our skies?

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