My first candidate would be roar sound. In any case 100 miles/ 160Km is an impressive distance.

Whales were reported communicating at a distance of 60 miles / 100Km at least and in theory sound could travel 100 miles easily in the water. Howling monkeys roars can be heard at 3 miles (4.8Km), and are seen as the loudest terrestrial mammals but low frequency sounds in Lion roars can be heard at 5 miles.

I would assume that either he was aware previously of the female territory (maybe both tigers were roaring near the frontiers of both territories while wandering); or that both tigers were attracted to the same place by an external factor (plenty of preys born in a place at a given time, or a water source).