An interim update of the State of the World's Migratory Species Report has warned that nearly half of migratory species populations are falling worldwide. The report is prepared under the Convention on the Conservation of Migratory Species of Wild Animals (CMS) of the United Nations Environment Programme (UNEP). It reviews the status of 1,189 migratory species listed under the CMS treaty. About 49% of their populations are declining and around 24% of the species face extinction risk. Key threats are habitat loss, overexploitation, infrastructure development and diseases such as Highly Pathogenic Avian Influenza (H5N1).