The insect sound is at exactly the same level all the way through the audio. This would not happen if a person was walking closer or further away from the source of the sound. In other words the background noise should change as he was walking.
There is also a lot of reverberation on the calls. If they were that close a similar reverberation would be heard from both however, the call on the right has way more reverberation than the first call or the call on the left.It sounds like the calls were made in a cave...When I hear the calls my bullometer cranks off the scale.
Others have pointed out some inconsistencies with the walking and I think they are correct. I would add that the walking seems to be at the same level all the way through just like the background (insect) noise. Each step would fall slightly differently making a difference in volume depending upon the debris and makeup of the walkway. The walking sound is way to consistent and when there are obviously two walkers the sound is still consistently at the same level.