Rinse ostrich and pat dry.
In a 10- to 12-inch frying pan over high heat, melt butter. When hot, add ostrich in a single layer. Brown on each side, cooking until rare or medium-rare (red in center, cut to test), 4 to 5 minutes total, or to taste (well-done ostrich is dry).
Remove pan from heat, quickly transfer the meat to a platter, and keep it warm.
Add port, cream, and cheese to pan; stir over high heat until reduced to about 1/3 cup. Pour sauce over the meat. Season to taste with pepper and salt.