Ibis最新文献

A robust understanding of the mechanisms driving demographic change in wild animal populations is fundamental to the delivery of effective conservation interventions. Demographic change can be driven by variation in adult survival, recruitment of juveniles into the breeding population or breeding productivity – the number of fledglings produced per breeding pair. Across Europe, low breeding productivity in wader populations has been a significant driver of population decline, increasing the importance of gathering accurate data on breeding productivity. Monitoring wader breeding productivity is challenging because finding nests can be time-consuming and requires experienced fieldworkers; wader chicks are nidifugous and difficult to count due to their cryptic behaviour; and waders often have high re-laying rates following nest failure, meaning that hatching or fledging can be highly asynchronous. This paper reviews approaches to estimating breeding productivity where fieldworkers either record the agitation or alarm-calling behaviour of adults with dependent young, make direct observations of broods on survey visits, or both. Using a systematic literature search (restricted to Europe where most of these studies have taken place) we identified 38 peer-reviewed papers which used this approach. The productivity metrics produced can be divided into the following categories: (i) ‘Hatching Success’ (HS), (ii) ‘Fledging Success’ (FS) and (iii) ‘Young Fledged Per Pair’ (YFP), from the coarsest to the most precise. The first two metrics are most often used when direct observations of broods are not possible due to the behaviour of broods or vegetation structure; YFP is preferred if brood counts are possible. Design of an appropriate metric depends on (i) whether accurate brood counts are possible; (ii) whether adults exhibit diagnostic agitation behaviour when young are present; (iii) whether individual breeding territories are separable; (iv) whether re-nesting rates are assumed to be high; and (v) the availability of experienced surveyors (particularly where behavioural observations are required). Globally there are many wader species for which the methods described here could provide valuable information and we hope this review encourages further development or adoption of these methods.

Territorial defence depends on highly interrelated factors such as food abundance and conspecific density. We used Dupont's Lark Chersophilus duponti as a model species to evaluate the response of a territorial bird to a foreign male playback, examining how conspecific density, habitat quality and male body condition impact responses. The study was conducted in central Spain with variable male density. Response (yes/no), latency time, distance to the playback speaker, and the number of songs and other vocalizations were monitored for 5 min. Habitat quality was estimated using BlueNDVI vegetation index extracted from high-resolution drone imagery, which is a proxy for arthropod prey biomass. Conspecific density (Kernel Density Estimator) and male body condition were calculated to assess their effect on response and intensity. We applied generalized linear mixed models (GLMMs) to determine which factors predicted the response and its intensity. There was a greater response probability in areas with a higher density of conspecifics and in areas of poorer habitat quality (i.e. lower BlueNDVI values). In contrast, latency time was longer in areas with lower conspecific density. Intrasexual communication (singing and calling rates) increased with habitat quality. Intraspecific communication (other vocalizations) increased in poorer quality habitats and at a higher density of conspecifics. Body condition was not related to any variables. Our results suggest that male density, sometimes used as an indicator of an area being well conserved for the species, may reflect areas of poorer habitat quality occupied by unpaired floater males, whereas paired territorial males would occupy and defend higher quality areas, leading to lower density.

Establishing methods that allow for more focused management of wildlife under predator pressure may increase the efficiency of managing problematic predators. Non-invasive dietary analysis and identification of conservation-sensitive prey in the diet of ‘culprit’ predator individuals could help to facilitate this and is worthy of exploration. Recently on Phillip Island, Australia, Little Ravens Corvus mellori have emerged as a prominent predator on the clutches of burrow-nesting Little Penguins Eudyptula minor. We tested the feasibility of using non-invasive PCR approaches targeting the penguin mitochondrial 16S rRNA marker gene to establish whether penguin DNA could be detected in raven faecal samples, potentially enabling the identification of culprit ravens missed by extensive field observation. Using a metabarcoding approach, we examined the feasibility of non-invasively establishing other dietary items via high-throughput amplicon sequencing. We documented components of raven diet using the universal mitochondrial 16S rRNA, insect-specific ‘Chiar’ 16S rRNA and plant ITS2. The assemblage of dietary items did not differ with raven culprit status (i.e. a raven previously observed preying upon penguin), sex or date. Penguin was detected in the diet of some individuals classified observationally as non-culprits. Although some cases may conceivably have been false detections, other explanations include missed depredation events, consumption via scavenging or through secondary consumption (e.g. eating invertebrates that have consumed penguin). While this study found metabarcoding unreliable for unambiguous assigning of raven culprit status, at least as we implemented it, it may hold promise complementing observations if consumption via scavenging can be distinguished from direct depredation.

The vocal activity and detectability of tropical birds are subject to high levels of temporal heterogeneity, but quantifying patterns of diel and day-to-day variation in complex systems is challenging with traditional point count methods. As a result, research concerning stochastic temporal effects on tropical bird assemblages is limited, typically offering only broad conclusions, such as that overall activity is highest in the first few hours of the morning and some species are active at different times of the day. Passive acoustic monitoring introduces several advantages for studying temporal variation, particularly by enabling simultaneous and continuous data collection across adjacent sites. Here, we employed autonomous recording units to quantify temporal variation in bird vocal activity and observed species richness at an Amazonian reserve in Madre de Dios, Peru, a region featuring some of Earth's richest, most complex bird assemblages. We manually annotated 18 dawn hour recordings, collected simultaneously from three separate days at the same six sites, which represent various microhabitats and bird community compositions. We documented significant and consistent temporal variation in avian vocal activity levels and observed species richness within the dawn hour and across days. We found that temporal effects were stronger for vocal activity than for observed species richness and that vocal activity patterns over the course of the dawn hour varied between species. Our results indicate that overlooked temporal variation in Amazonian soundscapes may obfuscate the results of surveys that do not sufficiently account for temporal variables with simultaneous monitoring. While manual analysis of large volumes of soundscape data remains challenging, such data should be collected to supplement traditional surveys whenever possible. Rapid advances in the automated processing of acoustic data could lead to more efficient methods for reducing temporal bias and improving the calibration and accuracy of tropical bird surveys.

As biodiversity declines, wildlife conservation focuses on in situ and ex situ management strategies. Zoo-based breeding programmes are often designed to contribute to the conservation of species that are threatened in the wild. Diet contributes to the reproductive success, disease status and longevity of all animals. It is near-impossible to replicate a species' diet in captivity using only the species they consume in the wild, but the nutritional composition of a wild diet, if known, can be closely matched using commercially available foods for which the nutritional composition has been calculated. Ecological research has identified food items of importance in the diet of many species. However, the nutritional composition of these food items is rarely evaluated, even though the composition of wild food items is important in understanding the dietary adaptations and requirements of wildlife. In contrast, the nutritional requirements of domestic species are well researched and can be used to predict a range of plausible nutrient requirements of some wild species, especially those with similar life histories. Access to wild populations provides further opportunities for nutritional science to determine the requirements of individual species. Small-scale dietary experimentation undertaken at conservation institutions may show positive effects on health and welfare but is rarely published in the scientific literature. This review describes current standards in nutritional management of birds and recommends pathways for filling knowledge gaps. Research on mammals has dominated the nutrition literature, so there is a relative lack of nutritional management information for birds. We combine concepts of domestic animal nutrition with recent findings on the nutritional requirements of birds to provide a foundation for further studies of avian nutrition. We call for the broader zoological community to share data and collaborate on nutritional research to support conservation institutions in nutritional management of wild birds.

Background: Refractory arthritis is a common problem in routine rheumatology practice, and can be a diagnostic challenge. In these cases, chronic Tropheryma whipplei (T. whipplei) infection is an important differential diagnosis that should be considered.

Objective: Based on five clinical cases, this case-based review describes the diagnostic and therapeutic principles in the management of chronic T. whipplei infection.

Results: Whipple's disease is a multisystemic infectious disease caused by the bacterium T. whipplei. The disease typically manifests with arthralgia, weight loss and diarrhoea. Joint involvement often develops years before gastrointestinal symptoms occur. In addition to systemic manifestations ("classic Whipple's disease"), T. whipplei can also lead to localized joint infections without gastrointestinal involvement. Articular manifestations of systemic and localized T. whipplei infections are commonly misdiagnosed as a sign of various forms of autoimmmune arthritis.

Discussion: Whipple's disease and localized T. whipplei joint infection should be considered in the diagnostic work-up of refractory arthritis. Synovial fluid analysis by means of specific polymerase chain reaction-based testing for T. whipplei is diagnostically ground-breaking.

Migratory birds must fit three costly life-history events within the annual cycle, reproduction, moult and migration, to minimize their overlap and maximize survival and breeding success. However, some seabirds, such as Cory's Shearwater Calonectris borealis, overlap body moult and breeding, with flight feather renewal occurring in late chick-rearing. In contrast, the moult patterns of non-breeding adult (sabbatical) and immature Cory's Shearwaters, which also attend the colony during the breeding season, remain poorly understood. Furthermore, the potential implications of life-stage and breeding status trade-offs on moult status and colony attendance in non-breeders has rarely been investigated. Surveying different areas within one colony between June and September 2013 and 2014, we studied the age and breeding status composition of birds attending the breeding colony and scored moult of their body (breast and upper-neck), wing and tail feathers. We found that in addition to breeders (n = 165), 57.6% of the birds (n = 389) attending the colony were 4- to 10-year-old immatures (n = 132) and adult sabbatical shearwaters (n = 92). Sabbaticals and 8- to 10-year-old immatures (n = 28) were present at the colony during incubation, whereas only three sabbatical birds and no 8- to 10-year-old immatures were captured in late chick-rearing. Conversely, 4- to 7-year-old immatures arrived later in the season but were still present in late chick-rearing. Sabbatical and 8- to 10-year-old immatures were moulting body feathers at the same time as adult breeders, whereas, among 4- to 7-year-old immatures, older birds moulted earlier than younger birds. A larger proportion of sabbatical birds were replacing tail feathers compared with adult breeders. However, there was no evidence that sabbaticals or 8- to 10-year-old immatures differed in wing moult from adult breeders until August. Overall, our study shows that colony attendance by non-breeding adults and immatures is widespread in this population. The synchronous moult schedule of flight and body feathers across age groups at different life-history stages may suggest that this aspect of moult is controlled by environmental conditions.

Biodiversity, ecosystem services and human health are becoming increasingly integrated in the ‘One Health’ concept, including recognition of the impacts of biodiversity loss on human health. Birds have considerable potential to benefit human health through their contributions to ecosystem functioning, recreation, and provision of pest control and pollination services, commonly referred to as ecosystem services. To synthesize the pathways through which birds facilitate human health, a scoping review methodology was employed to search the primary literature for relevant information. Of the 125 articles containing empirical evidence that were categorized, reported benefits included tangible materials (e.g. food, income) and resiliency (e.g. supportive ecosystem services; 80%), aesthetic, cultural, recreational, socio-economic and spiritual benefits (65%), psychological benefits (25%), regulation of transmission and prevalence of infectious diseases (11%), and physiological benefits (10%). Direct and indirect health benefits provided by birds are discussed in this review, facilitating the proposal of a new pathway categorization. The health contributions of any taxon must be given greater attention with the aim of supporting conservation and to support the sustainable use of wild species.

Variation in relative interspecific brain size has been correlated with cognitive capacities in different animal groups. Bird nest construction is one of the most remarkable animal abilities, and has reached the highest diversification in the Passeriformes. Yet, its relationship with brain size is not fully understood. Here, we used a dataset of 455 species to address potential correlations between nest types (open and enclosed) and five categories of nest attachment mode, as well as a set of covariables, with relative brain mass (Rbmass) of passerine birds. Bayesian regression modelling with phylogenetic control revealed that nest attachment mode, rather than nest type, was associated with Rbmass variation, despite the strong effects of habitat, migration and phylogeny. A phylogenetic confirmatory path analysis suggested that Rbmass and nest attachment can interact via a direct evolutionary link and also through an indirect link mediated through habitat (vegetation density). Phylogenetic ridge regression indicated that Top suspended nests were associated with species close to a maximum relative brain size, and that Rim suspended nests were associated with brain size radiations and probably with the exploration of new ecological niches. Our study provides evidence that the construction of nests with different attachment modes requires different levels of cognitive abilities, and we provide insights into the relationships between passerine brain size and nest attachment diversification.

Vertebrate populations are often monitored as part of broader assessments of ecosystem status, where they are expected to provide information on the ability of the ecosystem to support higher-level predators. However, because many vertebrates are long-lived and often only subsets of their populations can be monitored, abundance may not be sufficiently responsive to ecosystem status to provide early warnings of impending changes. Marine birds are often used as indicators of ecosystem status but, due to their long lifespan and delayed recruitment to the breeding population, changes in abundance are generally slow and often difficult to interpret. Their breeding productivity is, however, also widely monitored and much more responsive to ecosystem status, but the relevance of variation in productivity may be difficult to assess. We propose a model-based indicator that integrates monitoring of abundance and breeding productivity through demographic matrix models. The metric of the proposed indicator is the expected population growth rate, given the observed level of breeding productivity. This expected growth rate is then compared with a threshold derived from the criteria employed for red-listing of threatened species by the International Union for the Conservation of Nature. We demonstrate the suggested approach using data from Black-legged Kittiwakes Rissa tridactyla in the Greater North Sea region, Northwest Europe. The proposed indicator shows that the current level of breeding productivity is expected to lead to a population decline of 3–4% per year, which is equivalent to a red-list status as Endangered for the species in this region. Our indicator approach is used in OSPAR's Quality Status Report 2023 and is expected to be used by European Union member states for reporting under the Marine Strategy Framework Directive in 2024. Our approach represents a major step forward in assessing the status of marine bird populations; the ideal next step would be to develop a coherent Integrated Population Modelling (IPM) framework that would allow inclusion of all data on population abundance and demography collected across the large and diverse marine ecosystems involved.