Recovery of American peregrine falcons along the upper Yukon River, Alaska

Abstract

American peregrine falcons (Falco peregrinus anatum) throughout North America declined following the introduction of dichlorodiphenyltrichloroethane (DDT) in 1947. In the 1960s, intensive studies were initiated in many areas of North America, including interior Alaska, to determine the cause of the decline and assess population status. From 1977 to 2015, we studied peregrine falcons along a 265‐km section of the upper Yukon River in east‐central Alaska. We counted occupied territories, documented breeding success and productivity, and collected unhatched eggs for contaminant analysis. We observed 1,602 occupied territories and 2,349 nestlings. Annual breeding success averaged 64%, and annual productivity averaged 1.54 nestlings/territory and 2.38 nestlings/successful territory. Annual rates of increase in the number of occupied territories were greatest in the late 1970s and 1980s (8.6%), moderate in the 1990s (2.8%), and least in the 2000s (1.5%). Reproductive metrics were highest in the late 1970s and 1980s, declining in recent years. As the number of occupied territories increased (14–60) and average nearest neighbor distance decreased (from 9.8 km to 2.6 km), breeding success declined (from 71% in the 1980s to 57% in the 2000s). Productivity, as measured by nestlings per occupied territory, declined (from 1.84 in the 1980s to 1.29 in the 2000s). Nestlings per successful territory also declined from 2.56 in the 1980s to 2.25 in the 2000s. Survey data for 1966–2015 reveal a declining population in the 1960s and early 1970s, increasing in the late 1970s through the early 2000s, and apparently stabilizing in recent years. The recovery of this local population took roughly 40 years, from a low of 12 occupied territories in early 1970s to 60 in 2012–2014. Importantly, the recovery of American peregrine falcons in Alaska occurred without captive breeding, releases, or nest site manipulations. Long‐term studies are essential in fully understanding the biology of any species, and this study provides insight into the unaided, natural recovery of American peregrine falcons in Alaska. © 2016 The Wildlife Society.

Intraspecific evolutionary relationships among peregrine falcons in western North American high latitudes

“…anatum ) peregrines in Alaska. This is consistent with data emerging from long-term field surveys that have documented an increase in the number of occupied territories along the upper Yukon River from 1970 to 2012 [ 27 ]. Although average generation times for western high latitude peregrine falcons are not known, given an average generation time estimate of 6.8 years for this species [ 78 ], the increase on the Yukon River would have occurred across approximately 6 generations.…”

“…Samples included in this study were obtained from: A) specimens in museum collections (the Monte L. Bean Museum, Provo, Utah (n = 16) and the Museum of the Zoological Institute in St. Petersburg, Russia (n = 7); B) a single blood sample from the Bird Treatment and Learning Center, collected by veterinarians or other clinical staff with permission of State and Federal wildlife authorities; and C) blood, eggs, epithelial swabs, or feather samples collected as part of past and ongoing field research [ 27 , 32 , 36 – 40 ], all collected with appropriate Federal and State or Provincial permits. The latter include appropriate permits from the U. S. Fish and Wildlife Service (all collections in the United States) and the Canadian Wildlife Service (all collections in Canada), site-specific permits for collections on lands administered by the National Park Service-and the U. S. Fish and Wildlife Service’s National Wildlife Refuge-system, the Washington State Department of Fish and Game (the San Juan Island samples), and the Alaska Department of Fish and Game (for scientific collection in Alaska).…”

“…This well-documented and unprecedented collapse extirpated peregrine falcons in many regions of North America [ 25 ], including major former strongholds such as the Appalachian region [ 26 ]. In some locales (e.g., the Yukon and Tanana rivers, Alaska [ 27 ]), localized human activity, such as road construction and take for falconry [ 26 , 27 , 28 ], may have exacerbated declines attributed to the pesticide 1,1,1-trichloro-2,2-bis ( p -chlorophenyl) ethane (DDT). Insular, non-migratory populations, including F .…”

“…In Alaska, which like Canada hosts all three nominal North American subspecies, recovery of peregrines occupying boreal and Arctic habitats commenced in the late 1970s, following the prohibition of DDT for agricultural purposes in 1972 [ 27 , 32 ]. Unlike elsewhere in North America, however, reintroductions were not conducted in Alaska; populations there were allowed to recover through natural recruitment and recolonization [ 19 , 20 , 33 , 34 ].…”

Population genomic analyses reveal a highly differentiated and endangered genetic cluster of northern goshawks (Accipiter gentilis laingi) in Haida Gwaii

“…An effective tool has been the listing of individual species or subspecies as Endangered or Threatened under the protection of laws such as the Species at Risk Act (in Canada) or the Endangered Species Act (in the United States). This protection has led to the recovery of species such as the peregrine falcon (Falco peregrinus; Ambrose, Florian, Ritchie, Payer, & O'brien, 2016;Watts et al, 2015), the Kirtland's warbler (Setophaga kirtlandii; Bocetti, Goble, & Scott, 2012), and pink sand-verbena (Ambronia umbellata; Parks Canada Agency, 2017).…”