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Message: <blockquote data-quote="mjh73" data-source="post: 1935080" data-attributes="member: 82187">For starters nowhere near that number are being released from the captive bred birds. In the 12 years that releases have been made since the 1991/1992 breeding season upto the 2005/2006 breeding season (the latest I can find data for) 315 birds have been released - an average of 26 per year. The program was suspended in 2009 because of problems with genetic diversity and suspected inbreeding depression.Approximately only half the females breed each year. And OBPs are relatively short lived. I don't think a (higher than expected) morbidity is believed to be the issue. As I understand it the low rate of reproduction means they are not breeding fast enough to offset the natural attrition suffered by a small migratory bird with a short lifespan.</blockquote>