A vulnerable species is one which has been categorised by the International Union for Conservation of Nature as likely to become endangered unless the circumstances threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as “vulnerable” may be common in captivity, an example being the military macaw. There are currently 4728 animals and 4914 plants classified as vulnerable, compared with 1998 levels of 2815 and 3222, respectively.