1. Department of Wildlife, Faculty of Forest Resource and Environment Management Vietnam National University of Forestry Xuan Mai, Chuong My Hanoi Vietnam
2. Bac Giang Agro‐Forestry University Bich Dong, Viet Yen Bac Giang Vietnam
3. Department of Fish, Wildlife, and Conservation Biology, Warner College of Natural Resources, Colorado State University, Departmental Delivery 1474 Colorado State University Fort Collins CO 80523‐1474 USA
4. Institute for Tropical Biodiversity and Forestry Xuan Mai, Chuong My Hanoi Vietnam
5. K. Lisa Yang Center for Conservation Biocoustics, Cornell Laboratory of Ornithology Cornell University 159 Sapsucker Woods Road Ithaca NY 14850 USA