Avian ecological functions can provide ecosystem service benefits to humans. Although the values of avian provisioning and cultural services are well understood, the values of supporting and regulating services are not. Through predation, transportation, and excretion, birds play various roles in terms of seed dispersal/pollination, controlling prey species populations, scavenging, and nutrient cycling. These behaviours provide benefits contributing to increased agricultural productivity, pest control, and habitat creation/maintenance for humans. Though attempts have been made recently to evaluate the economic significance of avian ecosystem services, such attempts remain scarce. In Japan, where people have traditionally enjoyed avian ecosystem services mainly in terms of their support of agricultural ecosystems, an understanding and evaluation of the value of avian ecosystem services is essential.