Our microphones are, by default, omni-directional. As such, they do not need to be aimed. For weatherproofing purposes, they should be mounted pointing slightly down (or straight down in areas of heavy wind and weather). For those models that need windscreens, they should always be present and not pushed up against the end of the microphone, so that there is an air gap between the windscreen and the microphone. Ultrasonic microphones should be mounted away from any reflective surface (trees, foliage, ground, water, walls, etc.)
This is a very difficult question to answer. It can vary widely depending on the volume and direction of the source, the humidity, foliage, and other factors. You may be able to hear an owl from half a mile away, but not be able to hear a mouse from a distance of fifty feet. As a rule of thumb, if you can hear it with your ears, the microphone will also hear it.