This is because they usually die in the new area where they are relocated. Squirrels typically don't bother my gardening because I bring in the feeders in April and don't put them out again until after frost. This keeps the bears away from the feeders also. And I use Squirrel Buster bird feeders and hot pepper suet. These are more expensive, but they absolutely work. Squirrels are resigned to eating the spilled seed on the ground underneath the feeders. If you want to limit the population of something, then limit its food source.