Demography and population trends of Whooping Cranes

Abstract

Previous studies of Whooping Crane demography used estimates of fecundity rates based on females in captivity, and breeding success was estimated based on either the number of unbanded pairs nesting or the number arriving in wintering areas with chicks. We analyzed demographic data from 12 cohorts of banded Whooping Cranes (Grus americana) from the Aransas National Wildlife Refuge/Wood Buffalo National Park (ANWR/WBNP) population that had not been compiled previously into a single data base and had not been included in previous population analyses. We estimated age‐specific survival and natality, parameterized an age‐structured density‐dependent model, and projected population sizes assuming two different estimates of wintering ground carrying capacity. Sixty‐seven of 132 birds banded between 1977 and 1988 formed nesting pairs, females first produced hatchlings when 3 to 7 yrs old, and the annual proportion of mature females that reproduced successfully ranged from 0.566 to 0.606. Population projections indicate that the down‐listing criterion of reaching a population size of 1000 individuals might be attained considerably later than the target year (2035) indicated in the Whooping Crane recovery plan. Even assuming that all suitable habitat within a ∼100‐km radius of their current winter range could be occupied, projections suggest that population size may be ∼700 in 2035, and might not reach 1000 individuals until the mid‐2060s. Based on their territorial behavior on the wintering grounds, long generation time and faithfulness to their migratory route, we suspect that the population growth rate may decrease markedly in the near future and the ANWR/WBNP population may remain below the target down‐listing size of 1000 individuals.

Haemosporida prevalence and diversity are similar in endangered wild whooping cranes (Grus americana) and sympatric sandhill cranes (Grus canadensis)

“…1.Ranges of the Mid-continent and Rocky Mountain populations of sandhill cranes in North America and AWBP whooping cranes. Ranges shown include breeding, winter and migration routes (Gil-Weir et al 2012; Krapu et al 2011). Locations where sandhill cranes included in this study were harvested are indicated.…”

“…Ranges shown include breeding, winter and migration routes (Gil-Weir et al 2012; Krapu et al 2011). Locations where sandhill cranes included in this study were harvested are indicated.…”

“…During winter 2015–2016, this population was estimated at 329 individuals (95% CI = 293–371; CV = 0·073) (Butler & Harrell, 2016), a substantial increase from a population low of 15 individuals. Population projections, however, indicate that whooping cranes may not achieve the down-listing criterion of a population size of 1000 individuals (Canadian Wildlife Service & US Fish and Wildlife Service, 2005) until the mid-2060s (Gil-Weir et al 2012). Although parasitic infection may be one factor limiting population growth, species management efforts cannot specifically account for infections because very few studies have investigated parasites in the birds (but see Forrester et al 1978; Bertram et al 2015), likely reflecting the challenges of conducting infectious disease surveillance in an endangered species.…”

100th anniversary of the passenger pigeon extinction: Lessons for a complex and uncertain future

“…Given the tools and technology of modern wildlife management, we would like to believe we could detect population declines as steep as the passenger pigeon experienced and intervene before it is too late. Given some caveats, we have repeatedly demonstrated that capability on smaller scales in time and space with several threatened and endangered species (e.g., California condors [ Gymnogyps californianus ; Meretsky et al , Walters et al , Finkelstein et al ], bald eagles [ Haliaeetus leucocephalus ; Bowerman et al , Watts et al , Mougeot et al ], whooping cranes [ Grus americana ; Cannon , Gil‐Weir et al , Butler et al ], and gray wolves [ Canis lupus ; Mech , Ripple et al , Treves et al ]).…”

Pre-migratory congregations of Red-crowned (Grus japonensis), White-naped (G. vipio) and Hooded (G. monacha) cranes in the Muraviovka Park for Sustainable Land Use in 1992

“…Ключевые слова: осенние предотлетные скопления; число птиц в стаях; сроки гнездования; поведение птиц Введение Все три вида журавлей находятся под охраной как на международном, так и государственном уровнях в России и большинстве стран, входящих в ареалы этих птиц (Higuchi et al, 2004;Marsh and Trenhan, 2008;Yuxiang et al, 2012;Gilber et al, 2016;Heim and Suanjak, 2016;Butler, 2017). Численность всех из них низка, имеет тенденцию к снижению, а наиболее многочисленный черный журавль относится к наименее изученным видам Палеарктики (Gil-Weir et al, 2012;Liying and Hongfei, 2012;Butler, 2013;Wang et al, 2014;Sun et al, 2015;Gilber et al, 2016;Zhou et al, 2016).…”