Restoring Aplomado Falcons to the United States
2013
Hunt, W Grainger | Brown, Jessi L. | Cade, Tom J. | Coffman, John | Curti, Marta | Gott, Erin | Heinrich, William | Jenny, J Peter | Juergens, Paul | Macías-Duarte, Alberto | Montoya, Angel B. | Mutch, Brian | Sandfort, Cal
Captive-bred fledgling Aplomado Falcons (Falco femoralis) were released along the coastal plain of southern Texas (839 birds from 21 sites during 1993–2004) and in the Chihuahuan Desert of western Texas (637 birds from 11 sites in 2002–2011) and southern New Mexico (337 from 10 sites during 2006–2012). The Texas coastal releases yielded two nesting populations: 15–18 pairs near Brownsville and 15 pairs on two islands near Rockport. Habitat in these areas is extensive open savanna, the ancestral condition over most of the region. Today, it is almost entirely dominated by farmland and brushland, the latter harboring the Great Horned Owl (Bubo virginianus), a major predator of the falcons. Conversely, releases in the Chihuahuan Desert have been unsuccessful in establishing a wild population in either area. Although 8–10 pairs were present in West Texas in 2009, by 2011 only one pair remained, and none were found in 2012, the apparent consequence of severe drought. A single pair documented in New Mexico in 2011 was associated with artificial feeding of prey birds. We concluded that the conservation and expansion of Aplomado Falcon populations on the Texas coastal plain will require the protection and management of existing breeding territories, and the creation and management of more brush-free savanna. Persistent drought, the reduction of prey populations, and high rates of mortality from raptor predation appear to preclude the reestablishment of Aplomado Falcons in western Texas or New Mexico.
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