Insect-feeding birds can help to reduce pest populations. Especially in inundated rice fields, these birds have no place to sit and rest. By providing perches, the farmer can invite more of these birds into the field.
Another way of providing perches is to grow a few Sesbania plants in the rice field. Besides serving as perches, these plants also improve soil fertility.
Dragonflies are beneficial insects that predate on other insects (including pests). They are strong flyers and are often seen hovering above the crops. They are known to also use the perches for resting.