Phenology of Territorial Sandhill Cranes on the Breeding Grounds in South-Central Wisconsin

2022 ◽  
Vol 187 (1) ◽  
Author(s):  
Matthew A. Hayes
Keyword(s):  
South Central ◽  
Breeding Grounds ◽  
Sandhill Cranes

scholarly journals Fall Age-Ratio Survey Design for Eastern Population Greater Sandhill Cranes

2019 ◽  
Vol 10 (2) ◽  
pp. 631-640
Author(s):  
David L. Fronczak ◽  
Elizabeth A. Rigby
Keyword(s):  
Migratory Birds ◽  
Survey Design ◽  
Adult Population ◽  
Recruitment Rate ◽  
River Valley ◽  
Spatial And Temporal Variation ◽  
Flock Size ◽  
Eastern Population ◽  
South Central ◽  
Sandhill Cranes

Abstract For migratory birds, wildlife managers can use the recruitment rate of young into an adult population to model population dynamics, manage harvest, or evaluate habitat. Few recruitment estimates exist for Eastern Population greater sandhill cranes Antigone canadensis tabida, and estimates are outdated and local in scale. Wildlife managers can use age ratios as an index to recruitment, and surveying at fall staging areas is efficient and cost effective. We created a systematic survey design for surveying eastern population crane age ratios in the Kankakee River valley (2013–2015) in northwestern Indiana and the south-central counties of Michigan (2014–2015). Using logistic regression, we investigated factors that may cause spatial and temporal variation in age ratios, including flock size, timing within season, state, year, random vs. incidental survey routes, and observer. We stratified our selection of survey routes using a core area of high crane abundance, but do not recommend stratifying due to the added complexity and low utility. Observers determined the age of 53,371 cranes and found that the proportion of juveniles in Eastern Population crane flocks (π = 0.113, 95% CI: 0.105 – 0.122) was similar to previous estimates for the population. Proportion of juveniles was greater for south-central Michigan than for the Kankakee River valley, decreased with flock size, increased with lateness in the season, and varied among observers. Our design accounted for both ecological sources of variation in age ratios as well as nuisance variation. We recommend that future surveys use our design as part of a monitoring plan for Eastern Population cranes to support harvest management of the population and ensure that future survey results are comparable across years.

Effects of territorial status and life history on Sandhill Crane (Antigone canadensis) population dynamics in south-central Wisconsin, USA

2019 ◽  
Vol 97 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Michael E. Wheeler ◽  
Jeb A. Barzen ◽  
Shawn M. Crimmins ◽  
Timothy R. Van Deelen
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Demographic Data ◽  
Bird Species ◽  
Adult Survival ◽  
Vital Rates ◽  
Management Actions ◽  
South Central ◽  
Sandhill Cranes

Population growth rate in long-lived bird species is often most sensitive to changes in adult survival. Sandhill Cranes (Antigone canadensis (Linnaeus, 1758)) have long life spans, small broods, and delayed first reproduction. Only territorial adult Sandhill Cranes participate in breeding, and territory acquisition reflects the interplay between the availability of suitable territories and the variation in mortality of adult birds occupying those territories. We estimated vital rates of a population at equilibrium using long-term resightings data (2000–2014; n = 451 marked individuals) in a multistate mark–resight model and used a stage-structured projection matrix to assess how strongly territorial adult survival affects population growth rate. Elasticity analysis indicated territorial birds surviving and retaining territories had a 2.58 times greater impact on population growth compared with the next most important transition rate (survival of nonterritorial adults remaining nonterritorial). Knowing how changes in vital rates of various stage classes will differentially impact population growth rate allows for targeted management actions including encouraging growth in recovering populations, assessing opportunity for recreational harvest, or maintaining populations at a desired level. This study also highlights the value of collecting demographic data for all population segments, from which one can derive reproductive output or growth rate.

scholarly journals Differential Survival of Yearling and Adult Female Mallards and its Relation to Breeding Habitat Conditions

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 297-308 ◽  
Author(s):  
Kevin W. Dufour ◽  
Robert G. Clark
Keyword(s):  
Age Differences ◽  
Anas Platyrhynchos ◽  
Breeding Habitat ◽  
Interactive Effects ◽  
Differential Survival ◽  
Female Age ◽  
South Central ◽  
Age Related ◽  
Breeding Grounds ◽  
Capture Recapture

AbstractInformation on age-specific survivorship is vital to understanding the dynamics of avian populations, but for many avian taxa, little is known about age-related variation in survival beyond the first year of life. We used capture-recapture data from a 16-year field study of female Mallards (Anas platyrhynchos) breeding in south-central Saskatchewan to evaluate survival-rate differences between females marked in their second year (yearlings) and those marked as adults (≥2 years old). Because the breeding season is a period of high mortality for female ducks, we further sought to determine whether age differences in annual survival might vary with wetland conditions on the breeding grounds. Capture-recapture analysis based on extensions of the Cormack-Jolly-Seber model suggested that survival was best modeled to include effects of female age, with yearling females surviving at a higher annual rate (0.58 ± 0.05 SE) than adult females (0.47 ± 0.03 SE). However, additional evidence suggested that age differences in survival were most pronounced in years of low wetland abundance. Recapture rate (indicative perhaps of breeding propensity) was best modeled to include interactive effects of female age and wetland abundance, such that yearling females were recaptured at lower rates than adults in years of low wetland numbers. Collectively, our findings support the hypothesis that reduced breeding by younger females results in elevated probabilities of survival. Whether this pattern reflects reproductive constraint or trade-off decisions on the part of young birds remains to be determined.Supervivencia Diferencial en Hembras Añales y Adultas de Anas platyrhynchos y su Relación con las Condiciones del Hábitat ReproductivoResumen. Para entender la dinámica de las poblaciones de aves es vital contar con información sobre la supervivencia específica por edad, pero para muchos taxa de aves se conoce poco sobre la variación en supervivencia en relación a la edad luego del primer año de vida. Utilizamos datos de 16 años de trabajo de campo sobre captura-recaptura de hembras de Anas platyrhynchos que se reprodujeron en el centro-sur de Saskatchewan. Con estos datos evaluamos las diferencias en la tasa de supervivencia entre hembras marcadas en su segundo año (hembras añales) y aquellas marcadas como adultos (≥2 años de edad). Debido a que la estación reproductiva es un período de alta mortalidad para las hembras, queríamos además determinar si las diferencias de edad en la supervivencia anual variaban en relación a las condiciones de las áreas reproductivas de los humedales. Los análisis de captura-recaptura basados en extensiones del modelo de Cormack-Jolly-Seber sugirieron que la supervivencia era modelada mejor al incluir los efectos de la edad de la hembra, con una tasa anual de supervivencia más alta para hembras añales (0.58 ± 0.05 EE) que para hembras adultas (0.47 ± 0.03 EE). Sin embargo, evidencia adicional sugirió que las diferencias en la supervivencia por edad fueron más pronunciadas en los años con menor número de humedales. La tasa de recaptura (tal vez indicativa de la predisposición a reproducirse) fue modelada mejor al incluir los efectos de la interacción entre edad de la hembra y abundancia de los humedales. De este modo, las hembras añales fueron recapturadas a una tasa menor que las hembras adultas en años con escaso número de humedales. Colectivamente, nuestros resultados apoyan la hipótesis de que una reducción en la reproducción por parte de las hembras más jóvenes da como resultado un aumento en su probabilidad de supervivencia. Aún queda por determinar en las aves jóvenes si este patrón refleja limitantes reproductivas o decisiones de compromiso.

Rapid growth of the Bar-headed Goose Anser indicus wintering population in Tibet, China: 1991–2017

2021 ◽  
pp. 1-16
Author(s):  
MARY ANNE BISHOP ◽  
DONGPING LIU ◽  
GUOGANG ZHANG ◽  
DROLMA TSAMCHU ◽  
LE YANG ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Winter Wheat ◽  
Population Growth ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Annual Growth Rate ◽  
South Central ◽  
Tibet Autonomous Region ◽  
Breeding Grounds ◽  
Wintering Population

Summary Four of China’s six wintering populations of “grey” geese Anser spp. declined during the last decade. In contrast, the Bar-headed Goose A. indicus wintering population in China’s Tibet Autonomous Region more than doubled. During six surveys in Tibet over a 27-year period (1991/92 to 2017/18 winters) we documented an annual growth rate of 6.8% in the Bar-headed Goose population – an increase from approximately 10,100 to 68,100 birds. We propose that in addition to the cessation of hunting, the population growth of Bar-headed Goose is being driven by changes in agricultural land use patterns in Tibet, the establishment of protected areas on the wintering and breeding grounds, and the impacts of climate change across the Tibetan Plateau. Consistent with this hypothesis, the sown area of winter wheat in Tibet has increased and geese have shifted from primarily feeding in crop stubble to planted winter wheat fields. We also found that the most rapid population growth coincided with a 1998 climate regime shift across the Tibetan Plateau resulting in warmer temperatures, an increase in net precipitation, the appearance of new lakes and changes in the water levels and surface area of historical lakes. We suggest that warmer temperatures and high-quality forage on the south-central Tibet wintering grounds may be enhancing over-winter survival, while on the breeding grounds the expansion of lakes and wet meadows is augmenting breeding and brood-rearing habitat.

Pairing chronology and mate selection in the American wigeon (Anas americana)

1983 ◽  
Vol 61 (8) ◽  
pp. 1733-1743 ◽  
Author(s):  
Richard A. Wishart
Keyword(s):  
Mate Choice ◽  
Small Groups ◽  
Mate Selection ◽  
Mate Preferences ◽  
Adult Males ◽  
South Central ◽  
Pair Bonds ◽  
Breeding Grounds ◽  
Lower Protein ◽  
Males And Females

The American wigeon (Anas americana) was studied during winter in southwestern British Columbia and on its breeding grounds in south-central Saskatchewan. Sex ratios ranged from 52.4 to 59.6% males. Wigeons courted in small groups but not all birds did so concurrently. However, by April all females were paired. Some winter pair bonds were temporary and observations of wild birds as well as a group of captives indicated that males and females exhibited mate preferences. Persistent aggression, dominance, mate attentiveness, and the performance of functional displays and aerial chases by males were important in acquiring a mate. Adult males in full alternate plumage tended to pair earliest. Those unable to obtain a mate were generally smaller and had lower protein and lipid reserves. These characteristics with which mate choice was correlated were also those which were important during nesting later on.

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