Birder's Guide

OCT 2014

Birder's Guide is the American Birding Association's newest publication. Each issue focuses on a key subject, providing tips from experienced birders on a wide variety of topics like Travel, Listing & Taxonomy, Gear, and Conservation & Community.

Issue link: http://bg.aba.org/i/392347

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37 October 2014 | Birder's Guide to Listing & Taxonomy The Peregrine Fund created the overall restoration effort in 1996 and the Rocky Mountain Bird Observatory (RMBO) cur- rently maintains a project monitoring nest productivity of a small population of Aplomado Falcons in Chihuahua, Mexico; their numbers have plummeted because of drought and conversion of grasslands to agriculture. According to the Fund's latest report, published in September 2013 , the number of occupied territories decreased from 25 per year from 1997–2004 to eight in 2010. More recently, of only three observed nesting attempts, just a single fedgling was produced. The Fund's report concludes, "If the current trends in grassland conversion and reproductive success continue, the last known desert-dwelling Aplomado Falcon population in Chihuahua will be- come extinct during this decade". RMBO wants to forestall such a fate. Its program includes an effort to engage land- owners in maintaining their acreage in ways that are both proftable and environ- mentally friendly to Chihuahua's grass- land birds. RMBO's goal is to support fve successful breeding pairs of Aplomado Falcons and enroll 500,000 acres by 2020 . RMBO's hope is a poignant epilogue to a June 1980 article in Birding (pp. 92–102) by Dean P. Hector, an authority on the species. The article is titled "Our Rare Falcon of the Desert Grassland", and it taught many ABA members for the frst time about the Aplomado Falcon's biology, identifcation, and troubled population. Hector noted that the species had virtu- ally disappeared north of the border, and it had declined in other parts of Mexico. "Perhaps, someday, this colorful falcon will once again nest regularly in the grass- lands of the southwestern United States", Hector wrote optimistically. Looking back 34 years later, now as an assistant professor at Huston–Tillotson University in Austin, Texas, he comments to Birder's Guide, "Reintroduction work has obviously made it easier for our bird- ing public to see this dashing falcon north of Mexico. It has also created the perfect fagship species for grassland restora- tion projects in northern Mexico, and it has accelerated an anticipated northward range extension. Maybe one of these days I will actually be able to watch them chas- ing White-winged Doves near my home in central Texas, just like I used to do in northern Veracruz". Acknowledgments I thank Grainger Hunt, Dean P. Hector, Sartor Williams III, Michael L. P. Retter, and Ted Floyd for their comments and improve- ments on previous drafts. Glossary DDE: Dichlorodiphenyldichloroethylene is an organic chemical that enters the envi- ronment as a residual, or "breakdown", product of DDT. This compound, not the DDT itself, is the contaminant that accumulates up the food chain, is ingest- ed via prey, and persists in a bird's body for many years as an agent of reproduc- tive failure. DDT: Dichlorodiphenyltrichloroethane is a synthetic chemical compound developed This Aplomado Falcon, photographed in 2010 near Laguna Atascosa National Wildlife Refuge, is sporting an aluminum band on its leg and is clearly one of the birds released as part of the repatriation program. Photo © Alfred Bruno in the 1940s to combat insect-borne hu- man disease when used as a pesticide. It has been used widely to control insects in environments ranging from huge crop felds to residential gardens. Because it is a hazard to humans' and other animals' health (emphasized in Rachel Carson's Silent Spring), its use as an agricultural insecticide has been banned in the U.S., Canada, and Mexico, but it is still permit- ted for controlling mosquitoes and other disease vectors. Hacking: The controlled release of young birds from an artifcial box or platform to introduce captive-bred fedglings into their natural habitat. The technique pre- pares the young for independent hunt- ing in the wild. Fledglings are housed, fed, and trained to fy and hunt on their own. The method has succeeded widely in restoring endangered raptors to their former ranges. Organochloride: An organic (carbon- based) chemical compound with at least one covalently bonded chlorine atom. Among the better-known organochlo- rides are DDT (a pesticide), "carbon tet" (a dry-cleaning agent), polyvinyl chloride (PVC plastics), and chloroform. These pollutants can be toxic to plants, birds, and other animals (including humans). Organochlorides of many forms can en- ter the environment via waste disposal, agricultural runoff, and incinerator effu- ent. The compounds persist in the envi- ronment long after their use has ended.

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