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

Abstract

Subspecies relationships within the peregrine falcon (Falco peregrinus) have been long debated because of the polytypic nature of melanin-based plumage characteristics used in subspecies designations and potential differentiation of local subpopulations due to philopatry. In North America, understanding the evolutionary relationships among subspecies may have been further complicated by the introduction of captive bred peregrines originating from non-native stock, as part of recovery efforts associated with mid 20th century population declines resulting from organochloride pollution. Alaska hosts all three nominal subspecies of North American peregrine falcons–F. p. tundrius, anatum, and pealei–for which distributions in Alaska are broadly associated with nesting locales within Arctic, boreal, and south coastal maritime habitats, respectively. Unlike elsewhere, populations of peregrine falcon in Alaska were not augmented by captive-bred birds during the late 20th century recovery efforts. Population genetic differentiation analyses of peregrine populations in Alaska, based on sequence data from the mitochondrial DNA control region and fragment data from microsatellite loci, failed to uncover genetic distinction between populations of peregrines occupying Arctic and boreal Alaskan locales. However, the maritime subspecies, pealei, was genetically differentiated from Arctic and boreal populations, and substructured into eastern and western populations. Levels of interpopulational gene flow between anatum and tundrius were generally higher than between pealei and either anatum or tundrius. Estimates based on both marker types revealed gene flow between augmented Canadian populations and unaugmented Alaskan populations. While we make no attempt at formal taxonomic revision, our data suggest that peregrine falcons occupying habitats in Alaska and the North Pacific coast of North America belong to two distinct regional groupings–a coastal grouping (pealei) and a boreal/Arctic grouping (currently anatum and tundrius)–each comprised of discrete populations that are variously intra-regionally connected.

Status and trends of circumpolar peregrine falcon and gyrfalcon populations

“…However, postrecovery samples indicated that tundrius and anatum could be differentiated due to increased genetic diversity within southern anatum populations, likely due to use of exotic subspecies for captive breeding during the recovery phase (Brown 2007). Similarly, using Alaskan samples, Talbot et al (2017) indicated that although pealei could be genetically differentiated from tundrius and anatum, the latter two subspecies could not be distinguished genetically. Using samples collected during migration (1985 to 2007) at Padre Island, Texas, Johnson et al (2010) found little difference between tundrius and anatum, and suggested that delineation between the two subspecies breeding at northern latitudes was not justified.…”

The DDT‐induced decline influenced genetic diversity in naturally recovered Peregrine falcons (Falco peregrinus) nesting within the Alaska Arctic and eastern interior

“…Secondly, increases in the biases of genetic diversity metrics, influx of new alleles/haplotypes, population growth inferred in Bottleneck (Arctic), and variance of Ne across Pcrit values in post-decline periods suggest the recovery was also augmented by natural immigration. Prior research found that gene flow estimates among regions (post-decline) are asymmetric between Arctic Canada and Arctic Alaska (microsatellite data) and between Interior Alaska and Arctic Alaska (mtDNA data), with no genetic structure detected between Interior and Arctic Alaska (Talbot et al 2017). Thus Peregrine Falcons were probably dispersing across the landscape as populations recovered.…”

“…Prior research found that gene flow estimates among regions (post‐decline) are asymmetric between Arctic Canada and Arctic Alaska (microsatellite data) and between Interior Alaska and Arctic Alaska (mtDNA data), with no genetic structure detected between Interior and Arctic Alaska (Talbot et al . 2017). Thus Peregrine Falcons were probably dispersing across the landscape as populations recovered.…”

Peregrine Falcon Falco Peregrinus in Brazil: Natural History Through the Lens of Citizen Science

“…Even thought we classified the overwintering individuals into subspecies, it is important to men?on the debate around this subject: many authors argue about the validity of the dis-?nc?on between F. p. anatum and F. p. tundrius based on morphological characters, due the process used for the reintroduc?on of the species in North America (Brown et al 2007, Talbot et al 2017. Analysis of the evolu?onary rela?onship between the three North American subspecies suggests that there is no gene?c differen?a?on from individuals iden?fied as F. p. tundrius and F. p. anatum from higher la?tudes; besides, there is gene flow between popula?ons of these subspecies and a high percentage of shared haplotypes (Talbot et al 2017). Nevertheless, the subspecies does not seem to affect migra?on ?ming and distribu?on in the wintering grounds (Table 1).…”