Pelvis morphology suggests that early Mesozoic birds were too heavy to contact incubate their eggs

Numerous new fossils have driven an interest in reproduction of early birds, but direct evidence remains elusive. No Mesozoic avian eggs can be unambiguously assigned to a species, which hampers our understanding of the evolution of contact incubation, which is a defining feature of extant birds. Compared to living species, eggs of Mesozoic birds are relatively small, but whether the eggs of Mesozoic birds could actually have borne the weight of a breeding adult has not yet been investigated. We estimated maximal egg breadth for a range of Mesozoic avian taxa from the width of the pelvic canal defined by the pubic symphysis. Known elongation ratios of Mesozoic bird eggs allowed us to predict egg mass and hence the load mass an egg could endure before cracking. These values were compared to the predicted body masses of the adult birds based on skeletal remains. Based on 21 fossil species, we show that for nonornithothoracine birds body mass was 187% of the load mass of the eggs. For Enantiornithes, body mass was 127% greater than the egg load mass, but some early Cretaceous ornithuromorphs were 179% heavier than their eggs could support. Our indirect approach provides the best evidence yet that early birds could not have sat on their eggs without running the risk of causing damage. We suggest that contact incubation evolved comparatively late in birds.     

Social learning in birds and its role in shaping a foraging niche

We briefly review the literature on social learning in birds, concluding that strong evidence exists mainly for predator recognition, song, mate choice and foraging. The mechanism of local enhancement may be more important than imitation for birds learning to forage, but the former mechanism may be sufficient for faithful transmission depending on the ecological circumstances. To date, most insights have been gained from birds in captivity. We present a study of social learning of foraging in two passerine birds in the wild, where we cross-fostered eggs between nests of blue tits, Cyanistes caeruleus and great tits, Parus major. Early learning causes a shift in the foraging sites used by the tits in the direction of the foster species. The shift in foraging niches was consistent across seasons, as showed by an analysis of prey items, and the effect lasted for life. The fact that young birds learn from their foster parents, and use this experience later when subsequently feeding their own offspring, suggests that foraging behaviour can be culturally transmitted over generations in the wild. It may therefore have both ecological and evolutionary consequences, some of which are discussed.     

Dietary breadth of frugivorous birds in relation to their feeding strategies in the lowland forests of central Honshu,Japan

Variation in the dietary breadth of frugivorous birds, i.e. variation in the degree of dietary specialization, is a key factor for understanding the construction of the architecture of diffused fruit–bird interactions. However, little information is available on the dietary breadth of frugivorous birds in a community and the avian attributes influencing it. In this study, we evaluated and compared the dietary breadth of 23 frugivorous birds (including both seed dispersers and seed predators) in relation to their feeding strategies (depending on which the birds were categorized into four types as gulpers, grinders, crushers and peckers) and other avian attributes. In particular, we hypothesized that feeding types with long fruit‐handling time (i.e. crushers and peckers) have a narrow dietary breadth. Our analysis was based on the data obtained through long‐term volunteer monitoring in the lowland forests of Kanagawa prefecture, Japan. We evaluated the dietary breadth of the birds while controlling for differences in sampling efforts and seasonal variation in the available fruit assemblages among the birds. Our analysis revealed that there was a large variation in dietary breadth among the birds, even after controlling for differences in sampling efforts and seasonal variation in the available fruit assemblages. Feeding strategies of the birds defined their dietary breadth to some degree, but we found little support for the hypothesis that fruit handling determines dietary breadth. We also observed a large variation in dietary breadth among the gulpers, which act mainly as seed dispersers for plants, and this variation could not be explained fully by other avian attributes. Our results showed that variation in the dietary breadth of frugivorous birds is partly determined by their feeding strategies and suggested that other unknown factors may play a role in determining dietary breadth variation and in structuring fruit–bird interaction networks.     

鸟类惊飞距离及其影响因素

惊飞距离(FID)是指捕食者(包括人类)接近目标个体并导致其逃避时,捕食者与目标个体之间的距离。惊飞距离能很好地衡量动物个体在特定环境下的恐惧反应和风险权衡,是研究动物逃避行为的常用指标,并为物种保护提供科学依据。鸟类是研究逃避行为的理想对象,本文综述了影响鸟类惊飞距离的各种因素,可分为3类:栖息地因素(距隐蔽处的距离和生境开阔度等)、鸟类自身因素(生活史、体型和群体大小等)以及与捕食者相关的因素(捕食者的接近方向和速度等)。城市化也会影响鸟类的惊飞距离,导致城市中的鸟类通常比乡村生境的同种鸟类拥有更短的惊飞距离。习惯化、适应和生境选择是解释惊飞距离城乡差异的3种假说。研究鸟类的惊飞距离及其影响因素,有助于理解鸟类的逃避行为及其风险权衡机制,为物种保护中设立合理的缓冲区域及制定有效的保护管理措施提供科学依据。目前国内有关鸟类惊飞距离的研究多为行为观察和单一因素的影响,有待从不同因素的交互作用角度探讨鸟类的逃避行为并用于物种保护。     

Impact of Avian Influenza on Village Poultry Production Globally

Village poultry and their owners were frequently implicated in disease transmission in the early days of the highly pathogenic avian influenza (HPAI) H5N1 pandemic. With improved understanding of the epidemiology of the disease, it was recognized that village poultry raised under extensive conditions pose less of a threat than intensively raised poultry of homogeneous genetic stock with poor biosecurity. This paper provides an overview of village poultry production and the multiple ways that the HPAI H5N1 pandemic has impacted on village poultry, their owners, and the traders whose livelihoods are intimately linked to these birds. It reviews impact in terms of gender and cultural issues; food security; village poultry value chains; approaches to biosecurity; marketing; poultry disease prevention and control; compensation; genetic diversity; poultry as part of livelihood strategies; and effective communication. It concludes on a positive note that there is growing awareness amongst animal health providers of the importance of facilitating culturally sensitive dialogue to develop HPAI prevention and control options.     

Modes of Continuity and Change in Action Sign Systems

ABSTRACT

This paper opens with stories of continuity and change from ethnographic accounts. It proceeds to a brief examination of the use of film as a recording device for action sign systems, then to the work of two archaeologists in the field of dance and human movement. Next, the recording of sign languages is examined, and finally a case of recent transformation of a ritual (the Dominican rite of the Catholic Mass) is explored, followed by an exposure of some of the reasons why “transformations” occur in rituals, dances, and sign languages throughout the world.

Despite the growing interest among the human sciences in bodies, the notion of moving persons and their signifying acts/actions tends to remain absent from ethnographic accounts and sociocultural theory. Once it is realized that (1) people enact their selves to each other in words, movement, and other modes of action, and that (2) all human selves are culturally defined, as time/space itself is culturally defined, it then becomes possible to develop strategies for a systematic investigation of human actions.

It is argued that the adoption of movement literacy not only as a methodological resource, but as a further development in the evolution of social scientific disciplines, seems necessary. When literacy enters the picture, the understanding of continuity and change in patterned human movement across time will finally come into its own.     

Manipulations of sensory experiences during development reveal mechanisms underlying vocal learning biases in zebra finches

Biological predispositions in learning can bias and constrain the cultural evolution of social and communicative behaviors (e.g., speech and birdsong), and lead to the emergence of behavioral and cultural “universals.” For example, surveys of laboratory and wild populations of zebra finches (Taeniopygia guttata) document consistent patterning of vocal elements (“syllables”) with respect to their acoustic properties (e.g., duration, mean frequency). Furthermore, such universal patterns are also produced by birds that are experimentally tutored with songs containing randomly sequenced syllables (“tutored birds”). Despite extensive demonstrations of learning biases, much remains to be uncovered about the nature of biological predispositions that bias song learning and production in songbirds. Here, we examined the degree to which “innate” auditory templates and/or biases in vocal motor production contribute to vocal learning biases and production in zebra finches. Such contributions can be revealed by examining acoustic patterns in the songs of birds raised without sensory exposure to song (“untutored birds”) or of birds that are unable to hear from early in development (“early‐deafened birds”). We observed that untutored zebra finches and early‐deafened zebra finches produce songs with positional variation in some acoustic features (e.g., mean frequency) that resemble universal patterns observed in tutored birds. Similar to tutored birds, early‐deafened birds also produced song motifs with alternation in acoustic features across adjacent syllables. That universal acoustic patterns are observed in the songs of both untutored and early‐deafened birds highlights the contribution motor production biases to the emergence of universals in culturally transmitted behaviors.     

Cultural Specificity and Comparison in Psychiatric Epidemiology: Walking the Tightrope in American Indian Research

Increasingly, the mental health needs of populations are measured using large-sample surveys with standardized measures and methods. Such efforts, however, rarely include sufficient number of smaller, culturally defined populations to draw defensible conclusions about their needs. Furthermore, without some adaptation, the standardized methods and measures may yield invalid results in such populations. Using a recently completed psychiatric epidemiology and services study with American Indian populations as a case example, this paper outlines issues facing epidemiologists working in such culturally diverse contexts. The issues discussed include the following: (1) persuading the scientific community and potential sponsors that work with distinct or culturally defined populations is important; (2) framing research questions and activities to meet the needs of communities; (3) defining a population of inference; (4) balancing the needs for comparability and cultural specificity; (5) maximizing scientific validity in light of the challenges in sample acquisition; and (6) developing and implementing data collection methods that uphold scientific standards but are also realistic given the context. The authors draw on their experiences—most recently in the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (AI-SUPERPFP)—to illustrate these issues and suggest ways to address each. A goal of this paper is to challenge those invested in conducting culturally valid epidemiologic work in such populations to better articulate the nature of these efforts.     

A new method for estimating locomotion type in large ground birds

Estimating the locomotion type of fossil ground birds is necessary for a better understanding of their ecology. Until now, only one method has allowed us to estimate the locomotion of fossil ground birds, but its application is complicated in the majority of fossil cases because it requires data from the three bones from the same hindlimb of one individual. Here, we propose a new method using only the maximum length and minimum width of the tarsometatarsus to estimate the locomotion of these fossil birds. This method is easy to apply and better distinguishes the intermediate cases between graviportal (walking) and cursorial (running) birds. This study shows that the species of large ground birds of the families Gastornithidae and Brontornithidae were all graviportal, probably because of their large body mass. More unexpectedly, it also shows that some Phorusrhacidae (e.g. Paraphysornis), usually described as cursorial birds, were in fact graviportal, probably because of their considerable body mass. All these new data about locomotion provide a better understanding of the ecology of fossil ground birds.     

The occurrence of two bill morphs of prions Pachyptila vittata on Gough Island

Prions Pachyptila are abundant seabirds in the Southern Ocean that have been used to infer environmental change, but this relies on an understanding of their morphological diversity. Species limits among prions are largely defined by the size and structure of their bills. The broad-billed prion P. vittata, which breeds at temperate islands in the central South Atlantic Ocean and around New Zealand, is the largest species with adult bill widths averaging 21–22 mm. We report local differences in bill sizes on Gough Island, with typical adults breeding in some areas and narrower-billed birds in other areas (average bill width 18–19 mm, although at one site there was a second mode at bill widths of 16–17 mm). The narrow-billed birds have slightly shorter bills, heads and wings (averaging 1–2 % smaller than typical adult broad-billed prions), but the difference in bill width is much more marked (15 %). The small-billed birds differ from typical broad-billed prions in having blue colouration in the upper mandible and are similar in size to MacGillivray’s prion P. [salvini/vittata] macgillivrayi from Amsterdam and St Paul islands in the temperate Indian Ocean. The occurrence of two prion morphs on Gough Island raises intriguing questions about their ecology and systematics. Small-billed birds breed 3 months later than large-billed birds, suggesting that they are a separate species, not an example of bill polymorphism.     

Host immune defence and migration in birds

Migratory birds are exposed to at least two different parasite faunas during their annual cycle, while resident birds only experience a single parasite fauna. Migratory birds should therefore have evolved mechanisms to control or reduce the negative impact of infections from a more diverse parasite fauna. In a comparison of pairs of closely related species of birds that differ with respect to whether they are migratory or residents, the size of two immune defence organs (the bursa of Fabricius and the spleen) was consistently larger in the migratory species. Since the bursa is only found in juvenile, sexually immature birds, we conclude that immune defence adaptations to the impact of a more diverse parasite fauna in migrants already exist before the start of the first migration. Interspecific differences in investment in immune defence between migratory and resident birds have implications for our understanding of complex host–parasite interactions, the acquisition of new hosts by parasites, and the susceptibility of migratory birds to environmental perturbations.     

Reptilian Cognition: A More Complex Picture via Integration of Neurological Mechanisms,Behavioral Constraints,and Evolutionary Context

Unlike birds and mammals, reptiles are commonly thought to possess only the most rudimentary means of interacting with their environments, reflexively responding to sensory information to the near exclusion of higher cognitive function. However, reptilian brains, though structurally somewhat different from those of mammals and birds, use many of the same cellular and molecular processes to support complex behaviors in homologous brain regions. Here, the neurological mechanisms supporting reptilian cognition are reviewed, focusing specifically on spatial cognition and the hippocampus. These processes are compared to those seen in mammals and birds within an ecologically and evolutionarily relevant context. By viewing reptilian cognition through an integrative framework, a more robust understanding of reptile cognition is gleaned. Doing so yields a broader view of the evolutionarily conserved molecular and cellular mechanisms that underlie cognitive function and a better understanding of the factors that led to the evolution of complex cognition.     

Primitive Warfare and the Ratomorphic Image of Mankind

The most influential current explanations of preindustrial violence and warfare see it as determined by factors and forces entirely external to human beings and their motives and purposes. This article critically examines the most prominent of these approaches—behavioristic, sociobiological, and ecological-functional—and some of the assumptions underlying them. Then, drawing on ethnographic data from a society known for its peacefulness—the Semai Senoi—the article offers an alternative conception of action, one that views human behavior, including warfare and nonviolence, as purposive, and that sees human beings as active decision makers picking their ways through fields of options and constraints in pursuit of individually and culturally defined goals in a culturally constituted reality which they themselves are actively constructing.     

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis,a Recently Emerged Bacterial Disease

Leukocyte profiles (relative numbers of white blood cell types) have been used by a growing number of ecological studies to assess immune function and stress in wild birds. House Finches (Carpodacus mexicanus) in eastern North America are susceptible to an eye disease caused by the bacterium Mycoplasma gallisepticum, providing the opportunity to examine whether leukocyte profiles are associated with infection status and other host characteristics. In this study, we compared blood smears from 297 wild House Finches with and without conjunctivitis to examine whether leukocyte profiles were associated with the presence and severity of mycoplasmal conjunctivitis. We also evaluated the influence of age, sex, and molt on leukocyte profiles in both diseased and nondiseased birds. Of 243 House Finches of known age and sex sampled, 30% showed clinical signs of mycoplasmal conjunctivitis. House Finches with conjunctivitis had significantly higher heterophil to lymphocyte (H/L) ratios and harbored greater numbers and proportions of heterophils and monocytes than nondiseased birds. Leukocyte profiles of noninfected birds did not differ significantly with respect to sex, but young birds had significantly greater numbers of lymphocytes and total white blood cells than adults. Molting birds had significantly more eosinophils than nonmolting birds. Finally, House Finches with the most severe outward signs of conjunctivitis showed the most dramatic leukocyte changes relative to noninfected individuals, and increasing H/L ratios and monocytes in diseased birds were paralleled in a subset of birds that were recaptured during the study period. These results are consistent with patterns observed in domestic poultry and suggest that understanding patterns of leukocyte differentials in this host-pathogen system could improve our understanding of innate immunity and infectious disease risk in other wild passerines.     

Avian evolution: from Darwin's finches to a new way of thinking about avian forebrain organization and behavioural capabilities

The study of birds, especially the Galapagos finches, was important to Darwin in the development of the theory of evolution by natural selection. Birds have also been at the centre of a recent reformulation in understanding cerebral evolution and the substrates for higher cognition. While it was once thought that birds possess a simple cerebrum and were thus limited to instinctive behaviours, it is now clear that birds possess a well-developed cerebrum that looks very different from the mammalian cerebrum but can support a cognitive ability that for some avian species rivals that in primates.     

On the origin of feathers

The appearance of feathers defines the appearance of birds. A number of changes defined, preceded or accompanied the event. The changes were hierarchical in nature and included revolutions in genomic organization (i.e., HOX and the feather keratin genes), protein sequence and shape, the large scale organization of proteins into filaments, and in the geometry of the cells and their roles in the follicle. Changes at each of these levels differ or produced different products than found in its analog in reptiles. They are essentially unique to birds and produced an evolutionary novelty. I used analysis of extant structure and information on development to reconstruct key events in the evolution of feathers. The ancestral reptilian epidermal structure, while probably a scale or tubercles, is still unidentified. The structural genes of feather proteins (φ-keratin) are tandem repeats probably assembled from pre-existing exons. They are unlike the alpha-keratin of vertebrate soft epidermis. Amino-acid composition, shape, and behavior of feather keratins are unique among vertebrates. The 3-dimensional organization of the follicle and the developmental processes are also unique. Although we lack a complete understanding of the appearance and early role of feathers, they are clearly the results of novel events.     

The evolution of infidelity in socially monogamous passerines: neglected components of direct and indirect selection

A recent study by Goran Arnqvist and Mark Kirkpatrick in the American Naturalist (165:S26-S37) suggested that female polyandry in birds is not driven by females because quantitative genetic approximations of selection demonstrated that indirect selection for female infidelity is weaker than natural selection against it. Instead, it was argued that extrapair copulations are the result of antagonistic selection on male behavior driving female coercion. While the approach and framework of the study were very good, the conclusions of the study were premature because a number of potential adaptive components of polyandry were unaccounted for, and several critical assumptions are unsupported by the current empirical data. Our understanding of extrapair paternity in birds, and perhaps polyandry in general, will be improved by a better empirical understanding of the direct benefits of fertility assurance and postcopulatory cryptic female choice and the relationship between polyandry and male investment. In addition, we need to develop a greater awareness of the limitations of trying to study behavior by proxy in the molecular laboratory. Together, these challenges and the framework recently presented should improve our understanding of the true function of extrapair paternity in birds.     

Unravelling the migration and moult strategies of a long-distance migrant using stable isotopes: Red Knot Calidris canutus movements in the Americas

For long‐distance migrants, such as many of the shorebirds, understanding the demographic implications of behavioural strategies adopted by individuals is key to understanding how environmental change will affect populations. Stable isotopes have been used in the terrestrial environment to infer migratory strategies of birds but rarely in marine or estuarine systems. Here, we show that the stable isotope ratios of carbon and nitrogen in flight feathers can be used to identify at least three discrete wintering areas of the Red Knot Calidris canutus on the eastern seaboard of the Americas, ranging from southeastern USA to Patagonia and Tierra del Fuego. In spring, birds migrate northwards via Delaware Bay, in the northeastern USA, the last stopping point before arrival in Arctic breeding areas, where they fatten up on eggs of spawning Horseshoe Crabs Limulus polyphemus. The isotope ratios of feather samples taken from birds caught in the Bay during May 2003 were compared with feathers obtained from known wintering areas in Florida (USA), Bahia Lomas (Chile) and Rio Grande (Argentina). In May 2003, 30% of birds passing through the Bay had Florida‐type ‘signatures’, 58% were Bahia Lomas‐type, 6% were Rio Grande‐type and 7% were unclassified. Some of the southern wintering birds had started moulting flight feathers in northern areas, suspended this, and then finished their moult in the wintering areas, whereas others flew straight to the wintering areas before commencing moult. This study shows that stable isotopes can be used to infer migratory strategies of coastal‐feeding shorebirds and provides the basis for identifying the moult strategy and wintering areas of birds passing through Delaware Bay. Coupled with banding and marking birds as individuals, stable isotopes provide a powerful tool for estimating population‐specific demographic parameters and, in this case, further our understanding of the migration systems of the declining Nearctic populations of Red Knot.     

Sleeping and vigilance in Black-tailed Godwit

I studied the influence of position within the flock of the bird on the sleep-vigilance trade-off in individual Black-tailed Godwits Limosa limosa roosting at high tide. The peeking rate, the percentage of time during which its eyes were open and mean duration of peeks were highest in peripheral birds. The duration of the sleep posture, defined as the amount of time an individual sits or stands with its bill tucked beneath its scapulars, did not differ significantly between central and peripheral birds. The rate of agonistic encounters was minimal, in both peripheral and central birds. These observations suggest different benefits for both positions in the flock, mainly anti-predatory in the case of central birds and thermoregulatory in the case of peripheral birds. Electronic Publication