Brant (Branta bernicla)

Life‐history attributes of Arctic‐breeding birds drive uneven responses to environmental variability across different phases of the reproductive cycle

“…Snow geese employ their robust bill and specialized foraging techniques to access nutritious subsurface roots and shoots (Iacobelli & Jefferies, 1991 ), while longspurs can subsist on seeds (Custer & Pitelka, 1978 ) prior to the emergence of arthropods. Brant are relatively dependent on food resources that emerge only as temperatures warm and melting snow exposes appropriate foraging substrates (Lewis et al, 2020 ), but unlike semipalmated sandpipers, brant also carry significant endogenous reserves that can serve as buffers when food resources are inaccessible (Hupp et al, 2018 ).…”

“…In contrast, semipalmated sandpipers and Lapland longspurs (hereafter longspurs) are small‐bodied birds that rely on exogenously derived nutrients (insects and seeds) for egg production (Hobson & Jehl, 2010 ; Klaassen et al, 2001 ; Meijer & Drent, 1999 ). Brant (2–6 eggs; Lewis et al, 2020 ), snow geese (2–6 eggs; Hamann et al, 1986 ), and longspurs (2–8 eggs; Custer & Pitelka, 1977 ) also regulate their reproductive investment by producing variable numbers of eggs, but the clutch size of semipalmated sandpipers is essentially invariant (4 eggs; MacLean, 1972 ; Sandercock, 1997 ). Finally, brant (Lewis et al, 2020 ), snow geese (Mowbray et al, 2020 ), and semipalmated sandpipers (Holmes & Pitelka, 1968 ) produce precocial chicks that exit the nest shortly after hatch and are self‐feeding, but longspur nestlings are altricial and derive all their food resources from the provisioning efforts of adult longspurs (Custer & Pitelka, 1977 ).…”

Where east meets west: Phylogeography of the high Arctic North American brant goose

“…The pattern of admixture contrasts with Pacific black stocks (Lewis et al, 2020). The largest of these molting concentrations occur on the North Slope of Alaska and comprises individuals from several breeding colonies originating in Alaska and Canada (Bollinger & Derksen, 1996) As most pair bonds are likely formed at various stages during the annual cycle outside of breeding areas (Lewis et al, 2020;Lindberg et al, 1998), the higher proportion of admixture observed within Pacific brant is likely maintained by sympatry between Pacific and WHA brant during certain periods of the annual cycle. In comparison, banding and telemetry data for greater white-fronted geese did not detect dispersal events between Alaska and Asia (Wilson et al, 2018); however, genomic data showed that dispersal does occur albeit very infrequently (Wilson et al, 2022).…”

“…Because this species is characterized as having low reproductive rates and thus recruitment (Lewis et al, 2020), the continual recording of temporal changes in genetic diversity is still needed. This is important because changes in genetic structure in terms of allele richness and heterozygosity levels can yield changes in individual fitness components (i.e., genetic Allee effect) over a different timescale making its effect not as obvious as an ecological factor (Luque et al, 2016).…”

“…During the 1970s and 1980s, population numbers of brant nesting and wintering in Pacific locales in North America declined markedly, largely due to reductions in the nesting populations on the YKD during the 1970s and 1980s (Sedinger et al, 1994). Although numbers have relatively stabilized on both coasts (Lewis et al, 2020), brant populations have not significantly increased in size as have other Arctic geese species starting in the late 1980s (Olson, 2021).…”