From: A growing captive population erodes the wild Red-crowned Cranes (Grus japonensis) in China
Year | Size of estimated captive population (N i )a | Increase in the number of RCs per year (N i+1–N i )b | Number of new-born RCs per year (N b)c | Number of dead RCs per year (N d)d | Number supplementary RCs per year (N s)e | Number of cumulative supplementary RCs (N cs)f |
---|---|---|---|---|---|---|
1999 | 555 | 41 | 51 | 20 | 10 | 10 |
2000 | 596 | 44 | 55 | 21 | 11 | 21 |
2001 | 641 | 48 | 59 | 23 | 12 | 33 |
2002 | 689 | 51 | 63 | 25 | 13 | 46 |
2003 | 740 | 55 | 68 | 27 | 14 | 60 |
2004 | 795 | 59 | 73 | 29 | 15 | 75 |
2005 | 855 | 64 | 78 | 31 | 16 | 92 |
2006 | 918 | 69 | 84 | 33 | 17 | 109 |
2007 | 987 | 74 | 90 | 36 | 19 | 128 |
2008 | 1061 | 79 | 97 | 38 | 20 | 148 |
2009 | 1140 | 85 | 105 | 41 | 22 | 169 |
2010 | 1225 | 91 | 112 | 44 | 23 | 192 |
2011 | 1316 | 98 | 121 | 47 | 25 | 217 |
2012 | 1414 | 105 | 130 | 51 | 27 | 244 |
2013 | 1520 | ‒ | ‒ | ‒ | ‒ | ‒ |
Total | ‒ | 965 | 1186 | 466 | 244 | ‒ |