Avian paramyxoviruses (APMVs) constitute some of the most globally prevalent avian viruses and are frequently isolated from wild migratory bird species. Using 1,907 fresh fecal samples collected during the 2012 avian influenza surveillance program, we identified two serotypes of APMV: APMV-4 (n=10) and APMV-8 (n=1). Sequences for these isolates phylogenetically clustered with Asian APMV-4 and APMV-8 recently isolated from wild birds in Korea, Japan, China, and Kazakhstan. Analysis by DNA barcoding indicated that the Mongolian APMV-4 and APMV-8 strains were isolated from Anseriformes species including Mallards (Anas platyrhynchos) and Whooper Swans (Cygnus cygnus). The close genetic relatedness to Asian isolates, and to similar host species, suggested that wild bird species in the Anatidae family might play an important role as a natural reservoir in the spread of APMV-4 and APMV-8. However, we did not find conclusive evidence to support this hypothesis owing to the limited number of strains that could be isolated. Enhanced surveillance of poultry and wild bird populations in Asia is therefore crucial for the understanding of global AMPV transmission, ecology, evolution, and epidemiology.