Characteristics of Whooping Crane Home Ranges During the Nonbreeding Season in the Eastern Migratory Population

ABSTRACT In 2001, a reintroduced population of Whooping Cranes, known as the Eastern Migratory Population (EMP), was established in the eastern United States. The breeding range for the EMP was in central Wisconsin and the populated originally migrated to the Florida Gulf coast during the nonbreeding season. Beginning in approximately 2004-05, the wintering range for cranes shifted from the Florida Gulf coast to inland marshes in Florida. Between 2007-08 and 2017-18 the winter distribution of this population expanded north to include areas as distant as southern Indiana. To date, there has been no assessment of habitat use of the EMP across the current winter distribution. The objectives of this study were to identify factors influencing daily home range sizes of wintering Whooping Cranes in the EMP, describe habitat characteristics of areas used by cranes within their daily home range, identify the water depths and vegetation heights of used areas, and assess behavior associations with habitat. During two winters (2014-15 and 2015-16), we used radio-telemetry to track 20 and 23 groups of wintering Whooping Cranes, respectively, each for one full day. We recorded their location, behavior, and the habitat characteristics of their locations. Based on natural clustering of winter areas of Whooping Cranes, we grouped winter sites into three regions: North (Illinois, Indiana, Kentucky), Central (Tennessee, Alabama), and South (Georgia, Florida, Louisiana). We calculated home range sizes using a 95% kernel density estimate, and home ranges decreased in size from north (4.9 ± 2.8 km2) to central (3.1 ± 1.0 km2) to south (2.3 ± 0.5 km2). Home ranges in the south were also comprised of the greatest proportion of wetlands compared to other regions (south = 37%, central = 7%, north = 1%). To identify habitat characteristics of winter sites, we compared used locations to randomly generated locations within a crane’s home range separately by region. In the north region, cranes used agricultural areas more often than forests, and used areas with hydric soil that were potentially seasonally inundated during winter. In the central region, cranes selected for both agriculture and wetlands compared to forests. Cranes wintering in the south did not select habitat characteristics out of proportion to their availability within their home ranges. We also measured water depths and vegetation heights of used areas, respective to a crane. In all regions, cranes used areas with water or vegetation below the tibiotarsal joint more often than areas with deep water or tall vegetation. Lastly, we compared foraging and loafing behavior in three habitat types (agriculture, grasslands, and wetlands), both pooled and separately by region. Whooping Cranes in the north foraged more often in agriculture than in grasslands or wetlands. However, in the central region, cranes foraged equally in all three habitats, and cranes in the south foraged in either grasslands or wetlands. Loafing behavior was associated with wetlands compared to agriculture or grasslands in all three regions. The findings of this study are the first description of habitat characteristics of areas used by cranes wintering throughout the current and entire winter range of the EMP. Results from this study will inform land managers of wintering habitat use and can benefit conservation planning with respect to future reintroduction efforts of this endangered species

A PRELIMINARY STUDY OF THE INFLUENCE OF BREEDING AREA DENSITY ON SANDHILL CRANE HABITAT SELECTION IN SOUTH-CENTRAL WISCONSIN

We hypothesized that territorial sandhill cranes (Grus canadensis) in densely populated breeding areas occupy smaller home ranges that are richer in optimal habitat than those in less densely populated breeding areas. We analyzed satellite telemetry data collected from 2012 to 2016 for 3 and 2 sandhill cranes from dense and less dense breeding areas, respectively. Tracked sandhill cranes in a dense breeding area tended to have smaller home ranges (0.37-14.25 km2) with higher concentrations of wetlands (27%) and row crops (40%) than tracked sandhill cranes in the less dense breeding area (8.80-48.81 km2, 14% wetlands and 26% row crops). Studies on variation of breeding season habitat use will help to better understand the areas where breeding sandhill cranes are likely to congregate and can inform management and harvest decisions for sandhill cranes

EXAMINING WHOOPING CRANE BREEDING SEASON FORAGING BEHAVIOR IN THE EASTERN MIGRATORY POPULATION

Agricultural fields may provide an important supplementary foraging habitat for whooping cranes (Grus americana) in the reintroduced Eastern Migratory Population (EMP). We developed methods and gathered preliminary data regarding whooping crane foraging efficiency and habitat use to better understand the use of agricultural fields by breeding cranes. We generated a simple null hypothesis that cranes would spend more time in the habitat type (wetlands vs. agricultural fields) in which they were able to obtain a higher foraging efficiency to maximize food intake, along with several alternative hypotheses pertaining to reasons cranes may prefer wetlands or agricultural fields during periods of the breeding season regardless of foraging efficiency. We collected habitat use and measures of foraging efficiency (stepping rate, striking efficiency, and capture rate) from videos of 2 pairs of cranes recorded for a concurrent study. Cranes spent more time in the habitat with higher foraging efficiency during the pre-nesting period (wetlands) but more time in the habitat with lower foraging efficiency during the incubation period (also wetlands). There was no significant difference in foraging efficiency post nest-abandonment. Our data imply that cranes are willing to undergo lower foraging efficiencies in order to remain on territory during incubation. However, our data should be considered preliminary due to the small sample size of individuals studied

VIGILANCE OF NESTING WHOOPING CRANES IN JUNEAU COUNTY, WISCONSIN

Vigilance plays an important role in the detection of possible threats and reducing the risk of predation, including during the incubation period. We examined the visual vigilance of incubating whooping cranes (Grus americana) in Juneau County, Wisconsin, during the 2019 nesting season. We deployed 9 trail cameras and tagged crane presence and behavior in 32,801 photos which were used in our analysis. We assessed individual nest and environmental variables and their effects on vigilant behavior of incubating cranes using linear mixed-models. Vigilant behavior was defined by a posture in which the crane’s head was up, neck was erect, and bill was horizontal to the ground. Nesting whooping cranes were less vigilant during the night (x̄ = 14.3 ± 1.4% [SE]) than during the day (25.0 ± 0.7%), and cranes were less vigilant during precipitation events. Cranes nesting closer to closed forest were 11-12% less vigilant than those nesting at medium or far distances from forest. Lastly, cranes nesting in medium-sized wetlands were 4-5% more vigilant than cranes in small or large wetlands. Further research to determine if levels of vigilance affect nest success could help increase productivity for this population

WHOOPING CRANE NEST BUILDING IN SOUTHWEST INDIANA

The first documented case of whooping crane (Grus americana) nest building in Indiana is described. During spring 2015, a pair of whooping cranes did not leave their wintering grounds in Gibson County, Indiana, to return to their summering area in Wisconsin. Three nest platforms were discovered after the death of the female crane. To date, this is the only documented example of a whooping crane pair in the reintroduced Eastern Migratory Population (EMP) building nest platforms outside of Wisconsin. Although fidelity to the core nesting areas in Wisconsin is strong, and natal dispersal is usually \u3c30 km, this example from Indiana shows that whooping cranes in the EMP may have the potential to pioneer nesting areas far outside of core reintroduction areas

EFFECTS OF RELEASE TECHNIQUES ON PARENT-REARED WHOOPING CRANES IN THE EASTERN MIGRATORY POPULATION

Reintroduction of an Eastern Migratory Population (EMP) of whooping cranes (Grus americana) in the United States by release of captive-reared individuals began in 2001. As of 2020, the EMP has approximately 21 breeding pairs and has had limited recruitment of wild-hatched individuals, thus captive-reared juveniles continue to be released into breeding areas in Wisconsin to maintain the population. We investigated the effects of release techniques on survival, behavior, site fidelity, and conspecific associations of 42 captive-parent-reared whooping cranes released during 2013-2019 into the EMP. Individuals were monitored intensively post-release, then as a part of a long-term monitoring program, locational, behavioral, and habitat use data were collected and analyzed. Most cranes roosted in water post-release; however, we documented 4 parent-reared cranes roosting on dry land. Most cranes eventually associated with other whooping cranes; however, juveniles released near single adult cranes were less likely to associate with other whooping cranes during their first migration or winter than juveniles released near other types of whooping crane pairs or groups. Parent-reared and costume-reared whooping cranes had similar rates of survival 1 year post-release (69.0% and 64.4%, respectively). The highest risk of mortality was within the first 100 days post-release, and the leading known causes of death were predation and impact trauma due to powerline or vehicle collisions. Both costume- and parent-reared cranes had strong fidelity to release sites. We advise releasing parent-reared cranes near pairs or groups of whooping cranes and taking measures to reduce the risk of mortality during the immediate period after release (e.g., predator aversion training, marking powerlines)

TWENTY-YEAR STATUS OF THE EASTERN MIGRATORY WHOOPING CRANE REINTRODUCTION

Since the 10-year status update in 2011, the first parent-reared whooping cranes (Grus americana) were released in the Eastern Migratory Population, the ultralight program (UL) ended, and cranes were released at new sites in eastern Wisconsin. During 2011-2020, 117 captive-reared whooping cranes were released; 75 costume-reared (35 in UL and 40 in the Direct Autumn Release program) and 42 parent-reared. There were no significant differences in 1- or 3-year survival rates based on rearing technique or release site. The population size remained at about 100 cranes during 2010-2018 but then decreased during 2018-2020 due to a reduced number of releases of captive-reared cranes and low recruitment. Predation remained the leading cause of death (54.1% of confirmed cases) for cases in which the cause of death could be determined, followed by impact trauma (18.8%), gunshot (10.5%), and disease (9.0%). The winter distribution shifted northward into more agricultural landscapes, with the majority of the population wintering in southern Indiana or northern Alabama. The summer distribution remained concentrated in Wisconsin, and breeding areas expanded into eastern Wisconsin. As a management response to nest abandonments caused by avian-feeding black flies (Simulium spp.), the first clutch of eggs was removed from nests at Necedah National Wildlife Refuge (i.e., forced renesting), which increased renesting rates from 42% to 79%. In total, 152 cranes were confirmed to have hatched in the wild, 27 of which survived to fledging. Two male whooping cranes nested with female sandhill cranes (Grus canadensis) and produced hybrid chicks. Three cranes were removed from the population due to using an active air strip on an Air National Guard base. As of April 2021, the estimated population size was 76 individuals (38 females, 36 males, and 2 of unknown sex), 16 of which were wild-hatched

Directional Charge Separation in Isolated Organic Semiconductor Crystalline Nanowires

One of the fundamental design paradigms in organic photovoltaic device engineering is based on the idea that charge separation is an extrinsically driven process requiring an interface for exciton fission. This idea has driven an enormous materials science engineering effort focused on construction of domain sizes commensurate with a nominal exciton diffusion length of order 10 nm. Here, we show that polarized optical excitation of isolated pristine crystalline nanowires of a small molecule n-type organic semiconductor, 7,8,15,16-tetraazaterrylene, generates a significant population of charge-separated polaron pairs along the π-stacking direction. Charge separation was signalled by pronounced power-law photoluminescence decay polarized along the same axis. In the transverse direction, we observed exponential decay associated with excitons localized on individual monomers. We propose that this effect derives from an intrinsic directional charge-transfer interaction that can ultimately be programmed by molecular packing geometry

Biological Case Against Downlisting the Whooping Crane and for Improving Implementation under the Endangered Species Act

The Whooping Crane (Grus americana; WHCR) is a large, long-lived bird endemic to North America. The remnant population migrates between Aransas National Wildlife Refuge, USA, and Wood Buffalo National Park, Canada (AWBP), and has recovered from a nadir of 15-16 birds in 1941 to ~540 birds in 2022. Two ongoing reintroduction efforts in Louisiana and the Eastern Flyway together total ~150 birds. Evidence indicates the U.S. Fish and Wildlife Service (USFWS) is strongly considering downlisting the species from an endangered to a threatened status under the Endangered Species Act (ESA). We examined the current status of the WHCR through the lens of ESA threat factors, the USFWS’s Species Status Assessment (SSA) framework, and other avian downlisting actions to determine if the action is biologically warranted. Our research indicates that WHCRs are facing an intensification of most threat drivers across populations and important ranges. The AWBP is still relatively small compared to other crane species and most birds of conservation concern. To date, only one avian species has been downlisted from an endangered status with an estimated population of \u3c3,000 individuals. Representation in terms of WHCRs historic genetic, geographic, and life history variation remains limited. Also, the lack of spatial connectivity among populations, reliance of the reintroduced populations on supplementation, and continued habitat loss suggest that WHCR populations may not be resilient to large stochastic disturbances. Given that reintroduced populations are not self-sustaining, neither supplies true redundancy for the AWBP. Proposed downlisting before recovery plan population criteria have been met is objectively unwarranted 3 and reflects USFWS inconsistency across ESA actions. Only by incorporating basic quantitative criteria and added oversight into ESA listing decisions can we avoid an action as misguided as downlisting the Whooping Crane without consideration of its recovery plan criteria or ostensibly its population ecology

Serum Glutamate Levels Correlate with Gleason Score and Glutamate Blockade Decreases Proliferation, Migration, and Invasion and Induces Apoptosis in Prostate Cancer Cells

During glutaminolysis, glutamine is catabolized to glutamate and incorporated into citric acid cycle and lipogenesis. Serum glutamate levels were measured in patients with primary prostate cancer (PCa) or metastatic castrate-resistant PCa (mCRPCa) to establish clinical relevance. The effect of glutamate-deprivation or blockade by metabotropic glutamate receptor 1 (GRM1)-antagonists was investigated on PCa cells’ growth, migration, and invasion to establish biological relevance