How To Catch A Lion In The Sahara Desert

I think I'll go for the 'magneto-optical method.'

We plant a large, lense shaped field with cat mint such that its axis is parallel to the direction of the horizontal component of the earth's magnetic field. We put the cage in one of the field's foci. Throughout the desert we distribute large amounts of magnetized spinach which has, as everybody knows, a high iron content.

The spinach is eaten by vegetarian desert inhabitants which in turn are eaten by the lions. Afterwards the lions are oriented parallel to the earth's magnetic field and the resulting lion beam is focussed on the cage by the cat mint lense.