Asian hornbills have limited ex situ breeding success, yet these species are some of the most threatened of birds, in need of managed breeding programs. To optimize breeding and increase the sustainability of such populations, it is necessary to assess and improve their husbandry and welfare. Evidence to improve reproduction can be gathered through global husbandry surveys. A survey was sent out to all European Association of Zoos and Aquaria and Association of Zoos and Aquarium holders of the wreathed hornbill (Rhyticeros undulatus) and Papuan hornbill (R. plicatus) to determine predictors for ex situ breeding success. This research found that pairs that have spent more years together (p = .016) and that adding additional proteins to the diet (p = .006) are two significant predictors of breeding success for wreathed- and Papuan hornbill pairs. This paper found a general trend that successful hornbill pairs prefer nest boxes that are situated outside (p = .054). The behaviors of calling to each other and sitting in close proximity showed a general trend and were observed more frequently in successful pairs and, therefore, could be good indicators of bonded pairs. We recommend that ex situ institutions allow their hornbill pairs time to form strong bonds, and that pair compatibility is monitored regularly to ensure that such interactions are positive and not consistently negative. An increase in the percentage of dietary proteins, prior and during the breeding season appears to stimulate pairs to breed. If the management and husbandry alterations presented in this study are implemented, the sustainability of Rhyticeros hornbill populations may be enhanced.
Providing evidence-based care to animals is a common goal in zoos and aquariums. However, there are many understudied species with a lack of information available, which may result in suboptimal care for individuals of these species. Using preference tests to ask individual animals what they want can be an effective means to enhance their care, and subsequently, their welfare. Using 24-h remote monitoring, we assessed substrate, enclosure feature, and lighting preferences of five aquatic turtles (two wood turtles, one Blanding's turtle, and two spotted turtles) that share an indoor enclosure at Lincoln Park Zoo. In addition, we compared enclosure feature and lighting preferences between winter and summer to determine whether the turtles had changing seasonal preferences despite being housed indoors. We found that the wood turtles and Blanding's turtle had substrate preferences, whereas the spotted turtles did not. In addition, we found that the turtles' enclosure feature preferences were consistent between winter and summer, but the amount of time spent on land, logs, and in water varied by individual. Finally, we found that the turtles utilized areas with ambient lighting more than areas with a heat lamp or UV lamp; this was consistent between winter and summer. The turtle preferences observed in this study can contribute to the development of care strategies that support their welfare and, in turn, may inspire similar preference studies at other institutions as we collectively advance toward providing animals of all taxonomic groups with evidence-based care.
Conservation breeding programs for endangered species face challenges, notably in the development of husbandry techniques, complicated by the impracticality of conducting controlled experiments. To reduce uncertainty regarding what works in conservation breeding programs, it is essential to capture data. In avian breeding programs, the construction of quality nests and appropriate incubation and handling of eggs by the parents are essential prerequisites to the successful production of offspring. Here, we study factors influencing nest-building and parental incubation outcomes in 'alalā (Corvus hawaiiensis), which is extinct in the wild and numbers fewer than 130 individuals in human care. Using parent-incubated egg data from 2018 to 2021 (171 clutches, 55 pairs), we evaluated the role of husbandry factors in determining the quality of nests constructed by 'alalā and the likelihood of nest quality and other social and environmental factors to predict egg loss (breaking, cannibalization, or ejection of an egg from the nest). More than half of all eggs laid failed to reach the hatch date. Nest quality was the most influential predictor of egg loss, with eggs in higher quality nests more likely to reach the hatch date. Male age also influenced egg loss, with very young (3 years old) and older males (⪞12 years old) experiencing more egg loss. Furthermore, the two facilities and two aviary types also differed in the quality of nests 'alalā constructed, indicating that nest-building behavior can be influenced by husbandry practices. These findings reduce uncertainty and provide insights for recommended management interventions to facilitate successful reproduction in human care.
Ex situ breeding constitutes an important tool for species conservation; however, many reptile species are not managed sustainably under human care due to poor fecundity in ex situ settings. In this study, we tested whether the translocation of a seasonally reproducing species to a different environment results in decoupling of extrinsic signals and intrinsic conditions. The endocrinological patterns of plasma steroid sex hormones, follicular development, and mating behaviour of two female and two male sexually mature Aldabra tortoises (Aldabrachelys gigantea) in a zoological institution in the Northern hemisphere was aligned with enclosure climate data (mean monthly daylight duration, temperature, and precipitation) and compared with respective hormone patterns of wild individuals and climate conditions in the native habitat on the Aldabra Atoll in the Southern hemisphere. Whereas occurrence of mating behaviour was not considered a limiting factor, lack of ovulation and subsequent follicular atresia was the main reason for the lack of reproductive output. While it was impossible to elucidate the triggering factors of ovulation and the multifactorial complexity of reproduction was not fully addressed, this study indicates suboptimal temperature conditions and relative temporal shifts of interacting external triggers (temperature and photoperiod) in the zoo setting.
Melengestrol acetate (MGA) implants are a progestin-based reversible contraceptive used to manage fertility in animals. MGA implants are recommended for replacement every 2 years; however, reproduction may be suppressed longer if implants are not removed. In this study, we investigated whether the probability of reproducing (pR) differed among nonimplanted females, females with MGA implants removed, and females whose implants were not removed. In addition, since implant loss in hamadryas baboons is a concern, we explored whether female age, institution, implant placement year, implant location, or implant placement type (intramuscular vs. subcutaneous) differed for females whose implants were lost compared to those that were not. The pR differed significantly across all three treatment conditions with the nonimplanted group having the highest pR. The pR plateaued at 63% after 40 months for the implant-removed group compared to 96% after 84 months in the nonimplanted group. There was no reproduction after contraception if implants were not removed (7.83-45.53 months). In the nonimplanted group, pR was significantly higher for older and parous females. In terms of implant loss, we found that implant placement type was significantly associated with implant loss, such that there were fewer losses when implants were placed intramuscularly (IM) as compared to subcutaneously. Our results suggest that placing MGA implants IM is likely to reduce loss. When loss is prevented, MGA implants are an effective form of contraception and are reliably reversibly in most individuals when removed. However, if not removed, they can prevent reproduction longer than 2 years.
Habitat use monitoring is necessary for a comprehensive understanding of the biological and psychological requirements of animals under human care, facilitating improved exhibit designs and promoting animal welfare. Current studies focused on the space use of the exhibit while limited studies examined the pathway use of the zoo-housed animals. This study aimed to investigate the habitat use of An An, the world-oldest male giant panda (Ailuropoda melanoleuca) at Ocean Park Hong Kong using a pathway utilization monitoring method. The result showed uneven utilization of pathways favoring the upper area near his den over the lower area which required longer walking in the hilly exhibit. Moreover, the comparisons of walking directions showed a preference for gentle slopes during uphill movement and a favor for steep slopes during downhill movement. Our study also compared the walking distance between uphill and downhill movements and the results showed that An An walked longer distances heading upward than moving downward due to his choice of pathways. Our results are in line with the findings in the wild population, showing a preference for gentle slopes, especially in uphill movement. Our study demonstrated the value of the pathway monitoring technique. Due to its easy and time-effective use, this technique can be incorporated into the care teams' operation, providing valuable information on daily activity (e.g. accessing the walking ability of the aged animals by investigating the pathway use and walking distance) and habitat use. Consequently, the pathway monitoring technique can help improve exhibit designs promoting welfare.
Boreal chorus frogs (Pseudacris maculata Agassiz 1850) are a widespread amphibian in North America, but several populations are in decline. Specifically, we are developing captive breeding and reintroduction methods for the Great Lakes/St. Lawrence-Canadian Shield population. Here we present the effects of tadpole density, food variety, and addition of supplemental minerals to rearing water on the growth, development, and survival during the larval and metamorph/juvenile stages. We conducted two experiments using a factorial design. We found that low tadpole density (1 vs. 2 tadpoles/L) and high food variety (five food items vs. three food items) significantly increased tadpole body length and Gosner stage after 2 weeks (p < .001), increased survival to metamorphosis (p < .001), decreased time to metamorphosis (p < .001), and increased weight after metamorphosis (p < .001). On average, tadpoles in the high density/low food treatment, compared to the low density/high food, were 25% smaller after 2 weeks, had 3.9× lower survival to metamorphosis, took 1.25× longer to reach metamorphosis, and weighed 1.5× less after metamorphosis. In contrast, neither density (0.5 vs. 1 tadpole/L) nor mineral supplemented water affected growth and development, but tadpole survival was higher at 1 tadpole/L. Our findings demonstrate the feasibility of rearing boreal chorus frogs in captivity and provide guidelines for rearing this and similar species in a laboratory environment.
Zoos are often limited by exhibit design in the opportunities they can provide animals to express natural behaviors; however, the opportunity to perform certain natural behaviors is key to supporting good animal welfare. Traditionally, in zoos, naked mole rats (Heterocephalus glaber) are housed in gunite-lined acrylic chambers that replicate the look of their tunnel systems in the wild but don't offer the opportunity for natural digging and tunnel construction behaviors. In this study, naked mole rat behavior was evaluated when providing two different presentations of movable substrate added on to the original exhibit-a tank with loose substrate and a dig pit with hard-packed clay. We recorded 299 5-min focal observations with 30-s intervals and 30 group scans to understand behavioral changes across treatments (10 days of observation per treatment). Results were analyzed using Bayesian mixed models. Digging behavior emerged in both presentations of moveable substrate. A potential indicator of negative welfare, barrier-directed behavior, decreased when the mole rats had access to the tank of loose substrate. A potential indicator of positive welfare, exploratory behavior, increased with access to the dig pit when the mole rats had the opportunity to build tunnels. Additionally, affiliative social interactions increased, and aggressive interactions decreased with access to either presentation of movable substrate. The observed changes in colony behavior demonstrate that captive naked mole rats readily exhibited the natural behaviors of digging and tunnel building when the opportunity was presented, and the habitat modification likely improved naked mole rat welfare.
Endemic to only three known provinces in South Central Vietnam, Cuora picturata have faced extensive collection pressures for the food, medicinal, and pet trades. Further exacerbating their decline is the lack of protected areas where wild populations exist, with only one known population occurring within a protected area. With threats to wild populations persisting, the development of an assurance colony has been prioritized for C. picturata. The Asian Turtle Program of Indo-Myanmar Conservation has been operating the Turtle Conservation Center (TCC) in Cuc Phuong National Park since 1998. From 2020 to 2022, 24 C. picturata were acquired by the TCC from the illegal trade. With no ideal repatriation plan, these animals provided an opportunity for developing a captive assurance colony at the TCC to safeguard the species from extinction. As semi-aquatic species, box turtles in the genus Cuora are a unique group that shows variations in habitat use and behavior between species. Herein, we documented some specific courtship behaviors not yet described for C. picturata, providing insight into the unique reproductive behaviors of this species.