It's for the small birds as seen in other ops photos.
They do it where I live but in the early evening when it is still light.
They catch birds for song bird cages and eating.

 

The worst ones are the fine nets they set on bamboo poles around the birds sleeping areas then set of a cracker frightening whatever birds there are in to the net.    One year they caught hoopoes and a family of owls, one very old, plus many smaller birds, about 30 in all.    Most are just left to die as its almost impossible to remove the trapped legs and wings.    I took photos to the local govt office but ....    Eventually i pulled it down as well as a second one a hundred metres away, pulled down twice.     

 

Then there are the lizards they dig out from the ground

Those traps are called snares.  They were set on a trail, so were attempting to catch any animals that use the trail, probably for food.  Your wife can check around to learn what type of small game lives in your area.