The pidgeon may fly south with the sun or the house martin or the plover may seek warmer climes in winter, yet these are not strangers to our land?
Are you suggesting Drugs migrate? Not at all. They could be carried. What? A pidgeon carrying drugs? It could grip it by the bag! It's not a question of where he grips it! It's a simple question of weight ratios! A five ounce bird could not carry a one pound . Listen. In order to maintain air-speed velocity, a swallow needs to beat its wings forty-three times every second, right?