Re-introducing captive-bred juvenile northern aplomado falcons to south-central New Mexico, USA

Summary

The northern aplomado falcon (Falco femoralis septentrionalis), endangered under the US Endangered Species Act since 1986 after disappearing from south-central New Mexico around 1930, was targeted for reintroduction to the privately owned Armendaris Ranch, chosen in 2006 as the state's first release site, in a collaboration led by the Peregrine Fund, US Fish and Wildlife Service, and Turner Enterprises. From 2006 through 2011, 102 captive-born falcons were released using standard raptor hacking, held on elevated platforms before release at natural fledging age, with supplemental feeding of thawed quail extended well beyond the standard 40 days, and 20 artificial nest platforms installed in 2007 to compensate for a lack of abandoned stick nests the species depends on. Monitoring via surveys, trail cameras and VHF transmitters on ten falcons in 2011 found nesting pairs formed in 2007, 2009 and 2011, with successful fledging in 2007 and 2011 but a failed 2009 attempt; an unbanded female that attended feedings from 2007 to 2010 was believed to be one of the 2007 fledglings later involved in the failed nest. Despite these signs of local establishment, most released falcons' fates remain unknown, radio units mostly malfunctioned, and only three confirmed predator-caused mortalities were documented, leading researchers to conclude most released birds likely died before reproducing; no falcons have been released at Armendaris since 2012. The project rates itself a failure, attributing it to insufficient habitat quality, specifically inadequate prey and unfavorable predator distribution, that undermined survival regardless of release protocol.