id say harris both birds will take game and the red tail is probably physically the strongest bird and if you want to take bigger quarry such as hare and even fox with a big female id say redtail. but seems as thought it sounds like birds and rabbits are your quarry id say a harris. bit quicker off the mark and i believe a bit more talented and seem to be easier to get into peak condition but if you have time to work a red tail and get it fit theres no reason they cant take rabbit and the occasional game bird but the harris will probably find pheasants and the like slighty easier due to their