Non-predatory Bird Research Articles

Playing it by ear: gregarious sparrows recognize and respond to isolated wingbeat sounds and predator-based cues.

The ability to detect an incoming attack provides a final opportunity for an animal to avoid predation. In birds, vision is the main sensory mode in detecting attacks, but auditory cues likely play an important role. The role of auditory cues from predators themselves remains largely unstudied. We evaluated the ability of free-living, gregarious sparrows (Passerellidae) to recognize attacks based on the non-vocal sounds made by predators or indirect auditory cues of ongoing attacks, mainly in the form of brief wingbeat sequences from predatory and non-predatory birds. Behavioral responses to playbacks were video-recorded and expressed in terms of a flock's propensity to respond, either by flushing to cover, becoming vigilant, or both. Sparrows responded equally to hawk wingbeats and those of small passerines. Both predator and non-predator wingbeat sequences induced anti-predator responses, especially when played loudly. Loud control sounds, such as hammering, induced few responses. Birds also responded to the sounds of a walking and running terrestrial predator (a dog), but reactions to the walking predator often involved birds jumping onto objects for a better view of their surroundings rather than immediate flight to cover. In an additional experiment, we examined how characteristics of wingbeat sequences (i.e., the number and cadence of hawk wingbeats) affected passerine responses. It indicated that only two consecutive hawk wingbeats, presented at a natural cadence, are necessary to elicit a strong response to a playback. Single hawk wingbeats induced only weak escape responses, as did artificially slowed cadences. Birds in general likely possess the ability to recognize non-vocal, auditory cues of incoming attacks, which may be produced by approaching threats or departing congeners.

State Management of National Resources at the Conceptual Level - Images and Meanings of State Symbols

This article is a further continuation of the work on the review of the basics of state management of national resources (state and use), in relation to its system - forming function-state policy and political symbols (the conceptual level of management). From the system positions of the general theory of classification and systematization, the functions of state management of national resources are considered and the role and place of each of them in a single universal management circuit is determined. The role and place of political symbols (a sub-function of the conceptual-strategic level) are considered on the basis of the proposed invariant structure of the typical contour of state management of the state of national resources (operational-tactical level). From the modern state symbols of the Russian Federation, the iconic image two - headed eagle is selected and its prototypes and the origins of their origin, which are located in ancient times, are considered. To consider the evolution of the iconic images of state symbols of modern Russia, it is proposed to systematize and analyze them at different historical stages, to this end, systematize and analyze the following Old Testament images of power (state symbols) of various countries of the world: non-predatory bird, bird of prey, griffin, two-headed eagle, systematize and analyze the sacred images of power double-headed eagle and griffin in the symbolism of the countries of the world with the identification of their sacred meanings-binary (binary). Conclusions are drawn about the common origins of the origin and distribution of these Old Testament images of state symbols in the countries of the Indo-European community, the systematization and analysis of the Old Testament images of power (state symbols) of various countries of the world: non-predatory bird, bird of prey, griffon, double - headed eagle allows us to trace the evolution of the origin and formation of the main state symbol of Russia double-headed eagle, at the heart of the Old Testament images of power griffin and double-headed eagle in the symbolism of the countries of the world lie the sacred meanings of the universal and fundamental principle of reality (world, reality, being) - the duality (duality) of opposite, proportionate and balanced entities.

Accumulation and exposure assessment of persistent chlorinated and fluorinated contaminants in Korean birds

To date, information is scarce on the accumulation and potential risks of persistent chlorinated and fluorinated contaminants in birds. In this study, organohalogen contaminants (OHCs), such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and perfluoroalkyl substances (PFASs), were measured in the liver tissues of 10 bird species (n = 69) from Korea. Among the OHCs, PFASs showed the highest concentration, ranging from 5.40 to 11,300 (median: 294) ng/g wet weight. The median concentrations of OCPs and PCBs in all the bird samples were 147 and 81.9 ng/g lipid weight, respectively. The maximum concentration of perfluorooctane sulfonate (PFOS) observed in our bird samples was highest reported so far. Concentrations of OHCs in predatory birds were significantly greater than those measured in non-predatory birds, indicating the importance of diet and trophic position for bioaccumulation of these contaminants. In addition, different accumulation patterns of OHCs were found between predatory and non-predatory birds. Significant correlations were found between organochlorine concentrations and stable nitrogen isotope ratio (δ15N) measurements, whereas no correlation was found between PFASs and δ15N. Although the concentrations of PCBs and DDTs in birds were lower than the threshold levels, 25% and 49% of birds exceeded the toxicity reference value and predicted no effect concentration for PFOS, respectively, implying potential health risks to Korean birds.

Changing winter conditions in the boreal forest: the effects of fluctuating temperature and predation risk on activity and physiological stress level in bank voles

Due to global climate change, the winter conditions in the North are predicted to change, as the time with an intact insulating snow cover gets shorter or disappears altogether. For small mammals, this could cause exposure to strong temperature fluctuations and increased predation risk, inducing severe stress and leading to alterations in the physical condition and behavior. To test this, we exposed bank voles (Myodes glareolus) to different temperature regimes and cues of predator threat under laboratory conditions. The test animals experienced either a stable but cool temperature regime resembling the stable conditions under snow cover, or an unstable temperature regime with cold nights and warmer days simulating the climate change scenario with unstable winter. After 3 weeks, the animals were additionally exposed to owl calls or sounds of non-predatory bird species. Stress levels, activity, food consumption, and body mass were monitored. We observed that the voles exposed to unstable temperatures adjusted their normal, mostly nocturnal, and circadian activity pattern towards a more diurnal rhythm without any significant responses in their stress level. Introducing the sound manipulation elevated the stress levels in females but not in males. The sound-induced stress levels did not differ between the temperature treatments. However, the temperature regime tended to affect anti-predator behavior as individuals experiencing unstable temperatures and a threatening sound decreased their overall activity, unlike individuals under stable temperature treatments. It seems that behavioral plasticity in bank voles may diminish the risk of accumulation of stress in cases of multiple simultaneous stressors. The future course of many ecosystems in the northern hemisphere has raised many questions as climate change is predicted to have notable consequences especially in these regions due to alterations in winter conditions. Our results suggest that these environmental changes could alter the circadian activity pattern and possibly, even the anti-predator behavior of bank voles. However, the adaptability and behavioral plasticity in this species may diminish the risk of pathological accumulation of stress effects.

Behavioural and physiological responses of wood mice (Apodemus sylvaticus) to experimental manipulations of predation and starvation risk

Body weight and the levels of stored body fat have fitness consequences. Greater levels of fat may provide protection against catastrophic failures in the food supply, but they may also increase the risk of predation. Animals may therefore regulate their fatness according to their perceived risks of predation and starvation: the starvation–predation trade-off model. We tested the predictions of this model in wood mice (Apodemus sylvaticus) by experimentally manipulating predation risk and starvation risk. We predicted that under increased predation risk individuals would lose weight and under increased starvation risk they would gain it. We simulated increased predation risk by playing the calls made by predatory birds (owls: Tyto alba and Bubo bubo) to the mice. Control groups included exposure to calls of a non-predatory bird (blackbird: Turdus merula) or silence. Mice exposed to owl calls at night lost weight relative to the silence group, mediated via reduced food intake, but exposure to owl calls in the day had no significant effect. Exposure to blackbird calls at night also resulted in weight loss, but blackbird calls in the day had no effect. Mice seemed to have a generalised response to bird calls at night irrespective of their actual source. This could be because in the wild any bird calling at night will be a predation risk, and any bird calling in the day would not be, because at that time the mice would normally be resting, and hence not exposed to avian predators. Consequently, mice have not evolved to distinguish different types of call but only to respond to the time of day that they occur. Mice exposed to stochastic 24h starvation events altered their behaviour (reduced activity) during the refeeding days that followed the deprivation periods to regain the lost mass. However, they only marginally elevated their food intake and consequently had reduced body weight/fat storage compared to that of the control unstarved group. This response may have been constrained by physiological factors (alimentary tract absorption capacity) or behavioural factors (perceived risk of predation). Overall the responses of the mice appeared to provide limited support for the starvation–predation trade-off model, and suggest that wood mice are much more sensitive to predation risk than they are to starvation risk.

Heterospecific alarm call eavesdropping in nonvocal, white-bellied copper-striped skinks, Emoia cyanura

Many species benefit from listening to the vocalizations of their predators as well as the alarm vocalizations of other species. This eavesdropping is an important way to acquire information regarding predator location and threat magnitude. Previous studies have investigated lizards eavesdropping on predators, while others have studied lizards eavesdropping on alarm calls. Studies that examine lizard responses to playbacks of both predatory calls and heterospecific alarm calls are absent, even though eavesdropping may be especially important in nonvocal species. By comparing both types of calls, we can assess their relative importance to skinks and understand how skinks discriminate between these calls. We broadcast sympatric predator vocalizations and both alarm call and nonalarm social vocalizations from a nonpredatory bird (red-vented bulbul, Pycnonotus cafer) to determine whether nonvocal, white-bellied copper-striped skinks could discriminate among them. Upon hearing red-vented bulbul alarm calls, white-bellied copper-striped skinks reduced their rate of looking and increased their rate of bloating compared to a baseline period. However, they did not respond significantly to red-vented bulbul social calls or to vocalizations from potential predators. Our study is the first to look at the relative magnitude of response to playbacks of predator and heterospecific vocalizations in lizards. White-bellied copper-striped skinks most likely depend on heterospecific vocalizations for predator information because they are nonvocal and found low on the forest floor, making it harder for them to identify predators directly than through alarm calls of avian heterospecifics.

Response ofAnolis sagreito Acoustic Calls from Predatory and Nonpredatory Birds

Many studies indicate that various vertebrates and invertebrates use sensory cues to recognize predators and to evaluate predation risk. Lizards and birds frequently occupy the same habitats; consequently, avian predation on lizards has been implicated as an important selective pressure on lizard behavior. However, there are few studies on how lizards respond to nonvisual cues. The response of adult male Brown Anoles (Anolis sagrei) to calls of birds was studied to determine whether they use auditory cues as an indicator of predation risk from birds. Anoles responded significantly more often with head tilt (increased vigilance) during playback of predatory vocalizations (Kestrel and Red-tailed Hawk calls) compared with low-risk stimuli (nonpredatory bird calls and white noise). Responses to auditory cues suggest that male Brown Anoles are able to distinguish the calls of birds known to prey upon lizards from the calls of nonpredatory birds. More important, this study demonstrates that anoles, most of which are nonvocal, are able to obtain information about predation risk through the use of auditory cues and that the role of hearing in these lizards has been underappreciated.

Aerial “flycatching”: non-predatory birds can catch small birds in flight

Aerial flycatching — the lightning-fast seizure of flying small birds in the beak of larger, not normally predatory birds, only a few cases of which are treated in the literature — is here described and discussed for white storks (Ciconia ciconia) and crows (Corvidae).

Factors Affecting Interspecies Variation in Home-range Size of Raptors

Considerable work has been devoted to examining factors that affect interspecies variation in homerange size. Home ranges for most vertebrates increase with body mass and decrease with increased habitat productivity (e.g. McNab 1963, Schoener 1968, Harestad and Bunnell 1979, Lindstedt et al. 1986). Large species have high energetic requirements and presumably must occupy large home ranges to obtain sufficient food, but even small species occupy relatively large home ranges when the availability of food is low. Interspecific variation in home-range size also has been attributed to differences in age and sex (Harestad and Bunnell 1979, Schoener and Schoener 1982), dominance status (Schoener and Schoener 1982), and trophic status (McNab 1963, Schoener 1968). For example, McNab (1963) showed that mammalian hunters have larger home ranges than similar-sized croppers and suggested that this difference was due to less biomass of food per unit area being available at higher trophic levels. Raptors provide valuable insights into the factors that affect an animal's home-range size because they use many different hunting tactics and take many different kinds of prey (Snyder and Wiley 1976, Marti et al. 1993, Korpimaki and Marti 1995). Newton (1979:63) has shown that home-range size of raptors increases with body mass, and Schoener (1968) has shown that predatory birds have larger home ranges than similar-sized nonpredatory birds. Here, I extend Newton's and Schoener's analyses by asking the question: Does the way in which a raptor exploits its prey base influence the size of its home range? Assuming that raptor home ranges are determined, in part, by food availability (e.g. Marquiss and Newton 1981, Village 1982), at least four predictions can be made about the size of a raptor's home range. First, invertebrates generally occur in higher densities than mammals for a given body size, whereas mammals generally occur in higher densities than birds for a given body size (Greenwood et al. 1996, Silva et al. 1997). Hence, one would expect bird-eating raptors to have larger home ranges than mammal-eating raptors, which in turn should have larger home ranges than invertebrate-eating raptors. Second, predators specializing on a narrow prey base should have to range over a relatively large area in order to encounter sufficient prey, whereas gen-

Response of Non-Predatory Birds to a Simulated Small Mammal

Response of Non-Predatory Birds to a Simulated Small Mammal

RABIES ANTIBODIES IN SERA OF WILD BIRDS

Three hundred forty-three birds representing six orders and 22 species were examined serologically for antibodies against rabies. Low passive hemagglutination titers were observed in 23 samples. Fifteen of 65 (23.1%) predatory birds and 8 of 278 (2.9%) non-predatory birds were positive. Rabies antibody positive sera from non-predatory species were from species commonly thought to be scavengers suggesting the importance of the oral route for the presentation of rabies virus to birds.