Cool video ain't it a riot when you see your house cat do that kinda shit when they think they see something and they're stalking it.
Kept tripping it's sense too but not enough to spook it into flight.
@Olderfart would know way better I always heard, (with deer) you trip 1 sense they're on alert trip 2 senses they're gone. I've heard they'll do a head drop like they're reassured and about to eat then pop right back up to catch movement