SUMMARY OF MORTALITY AMONG CAPTIVE CRANES AT THE INTERNATIONAL CRANE FOUNDATION: 2000-2020

We reviewed mortalities of captive cranes at the International Crane Foundation (ICF) between 2000 and 2020 to provide broad insights into contemporary factors affecting the collection’s health and survival. Sixty-three deaths were documented in 13 of 15 crane species held in the ICF collection. The mean annual mortality during the study was 2.6% and the mean age (±SD) at death was 28.4 (±12.7) years. The overall total number of deaths of males and females was similar, but there was an association between sex and death of adult versus geriatric (\u3e25 years) cranes (P \u3c 0.01); males were more likely to die at geriatric age than females. Deaths were commonly associated with chronic health and management problems (n = 44, 79%) versus problems with an acute onset (n = 12, 21%). Common causes of death in captive cranes were due to musculoskeletal problems (44%), trauma (9%), and neoplastic disease (8%). Infectious pathogens were associated with respiratory (6%), reproductive (4%), and gastrointestinal (2%) deaths. Our findings add to previous reviews of mortality among captive cranes by detailing problems associated with progressive aging of individuals in the ICF collection

SERUM CHEMISTRY, BLOOD GAS, AND PHYSIOLOGICAL MEASURES OF SANDHILL CRANES SEDATED WITH ALPHA-CHLORALOSE

Capture techniques that lessen handling stress may also lessen pathologic influences on physiologic measures, improving the validity of these measures for use in individual health assessment of freeranging wildlife. Since 1990, the International Crane Foundation (ICF) has successfully used chemical immobilization with alpha-chloralose (AC; C6H11Cl3O6), a chloral derivative of glucose, to facilitate captures of sandhill cranes (Grus canadensis tabida) for ecological studies (Hayes et al. 2003). Although this chemical has been used orally for the immobilization of many species, the physiologic effects of AC are not well understood in cranes. The primary purpose of this study was to measure serum chemistry, venous blood gas, and physiological values in free-ranging sandhill cranes successfully immobilized using this technique

USE OF FRESHWATER PONDS BY WHOOPING CRANES DURING A DROUGHT PERIOD

Whooping cranes (Grus americana) spend nearly half their annual cycle in coastal habitats within and around the Aransas National Wildlife Refuge Complex (ANWRC) located in the central portion of the Texas Coast. When drought conditions prevail in their winter range and salinities in the local bays exceed 23 parts per thousand (ppt), whooping cranes must seek alternate sources of dietary drinking water (Stehn 2008, Chavez- Ramirez and Wehtje 2012). They begin frequent (often daily) trips to freshwater sources in upland areas. These trips may result in extra energy expenditures that can impact their overall health and ability to store energy for spring migration (Canadian Wildlife Service and U.S. Fish and Wildlife Service 2007). We opportunistically used game camera images obtained from a physiological research project (B. Hartup, unpublished data) to gain additional information on how whooping cranes used refuge-managed freshwater resources in relation to prevailing environmental conditions

THE IMPACT OF MARKING ON CRANES: AN ISSUE PAPER

As crane researchers and conservationists, our overarching objective is to learn and gather information about our study subjects while doing as little harm as possible. New technologies may be emerging too rapidly for researchers to assess the effectiveness or potential adverse effects of the devices, despite the ease and increasing accuracy of the information they provide. Researchers need to be able to gather information to answer various questions in a way that balances ethics and expense. With marking of cranes as a focal point, we discuss issues surrounding crane research based on various techniques, some health issues that are a direct result of marking cranes, and consultation with telemetry companies to improve design of devices to be deployed on cranes. We submit a Call to Action: create a global crane research working group under the oversight of the International Union for Conservation of Nature (IUCN) Crane Specialist Group (CSG), a group dedicated to promoting the study and conservation of the world’s 15 crane species

OSTEOARTHRITIS IN THE PELVIC LIMB OF CAPTIVE CRANES

We conducted an epidemiological study of osteoarthritis (OA) among the 15 captive crane species managed at the International Crane Foundation from 1973 to 2016. A retrospective review of 714 medical records found 37 cases of OA in 13 species of cranes and a corresponding period prevalence of OA of 5%. An analysis of the living captive crane flock as of 1 October 2016 (n = 115) found 12 active cases of OA (a point prevalence of 10%), and there was a statistical association between geriatric age classification (i.e., advanced age) and the presence of OA (P \u3c 0.01). The mean age of cranes with OA was 14 years greater than cranes without the disease (P \u3c 0.001). The prevalence estimates of OA from this review were somewhat lower than that from study of museum specimens, but this study similarly identified the tarsal joint as the predominant location of OA lesions in cranes

ENDOPARASITISM OF REHABILITATING GREY CROWNED CRANES IN RWANDA

Diseases such as parasitism can limit the effectiveness of conservation translocations depending on host-parasite dynamics at the site of release. The Rwanda Wildlife Conservation Association and the Rwandan government are rehabilitating and repatriating grey crowned cranes (Balearica regulorum) from illegal captivity to the wild at Akagera National Park in large numbers. Monitoring of cranes at the fenced soft-release site during 4 time points in 2017 showed 50-67% of fecal samples tested were positive for 1 or more parasites, most commonly nematodes (roundworms) of the Order Ascaridida. The prevalences and species diversity observed in the fecal samples were not dissimilar from preliminary surveys of 2 other populations elsewhere in Rwanda, suggesting no new management considerations are needed to accommodate the number of cranes at the release site or during the preceding quarantine period to prevent disease

ENDOPARASITISM OF REHABILITATING GREY CROWNED CRANES IN RWANDA

Diseases such as parasitism can limit the effectiveness of conservation translocations depending on host-parasite dynamics at the site of release. The Rwanda Wildlife Conservation Association and the Rwandan government are rehabilitating and repatriating grey crowned cranes (Balearica regulorum) from illegal captivity to the wild at Akagera National Park in large numbers. Monitoring of cranes at the fenced soft-release site during 4 time points in 2017 showed 50-67% of fecal samples tested were positive for 1 or more parasites, most commonly nematodes (roundworms) of the Order Ascaridida. The prevalences and species diversity observed in the fecal samples were not dissimilar from preliminary surveys of 2 other populations elsewhere in Rwanda, suggesting no new management considerations are needed to accommodate the number of cranes at the release site or during the preceding quarantine period to prevent disease

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP