Why Do Birds False Alarm Flight?

False alarm flighting in avian flocks is common, and has been explained as a maladaptive information cascade. If false alarm flighting is maladaptive per se, then its frequency can only be explained by it being net adaptive in relation to some other benefit or equilibrium. However, I argue that natural selection cannot distinguish between false and true alarm flights that have similar energetic costs, opportunity costs, and outcomes. False alarm flighting cannot be maladaptive if natural selection cannot perceive the difference between true and false alarm flighting. Rather, the question to answer is what false and true alarm flighting both have in common that is adaptive per se. The fire drill hypothesis of alarm flighting posits that false alarm flights are an adaptive investment in practicing escape. The fire drill hypothesis predicts that all individuals can benefit from practicing escape, particularly juveniles. Flighting practice could improve recognition of and response time to alarm flighting signals, could compensate for inter-individual and within-day weight differences, and could aid the development of adaptive escape tactics. Mixed-age flocks with many juveniles are expected to false alarm flight more than adult flocks. Flocks that inhabit complex terrain should gain less from escape practice and should false alarm flight less. Behavioural ecology framings can be fruitfully complemented by other research traditions of learning and behaviour that are more focused on maturation and motor learning processes.

A Critical Review of the Pharmacokinetics and Pharmacodynamics of Opioid Medications Used in Avian Patients

Opioid drugs are used to manage moderate to severe pain in mammals and avian species. In dosing opioids for a particular species, it is optimal to use dosing regimens based on pharmacokinetics or pharmacodynamics studies conducted in the same species as variability in the physiology among different species may result in differences in drug pharmacokinetics and pharmacodynamics. Unfortunately, dosing regimens are typically extrapolated from closely related avian species or even mammals, which is unideal. Therefore, this critical review aims to collate and evaluate the dosing regimens of selected opioids: tramadol, hydromorphone, buprenorphine, butorphanol, and fentanyl, in avian species and its related safety, efficacy and pharmacokinetic data. Our review found specific dosing regimens not described in the Exotic Animal Formulary for tramadol used in Indian Peafowl (Pavo cristatus), Muscovy Duck (Cairina moschata) and Hispaniolan Parrot (Amazona ventralis); hydromorphone used in Orange-winged Parrot (Amazona amazonica); buprenorphine used in Cockatiel (Nymphicus hollandicus), American Kestrel (Falco sparverius) and Grey Parrot (Psittacus erithacus); and butorphanol used in Hispaniolan Parrot (Amazona ventralis), Broiler Chicken and Indian Peafowl (Pavo cristatus). Cockatiel appeared to not experience analgesic effects for hydromorphone and buprenorphine, and American Kestrel exhibited sex-dependent responses to opioids. The selected opioids were observed to be generally safe, with adverse effects being dose-dependent.

Avian Use of Dairy Farm Ponds and Landowners’ Perceptions of Their Management for Wildlife Conservation

Farm ponds are among the last remaining lentic wetland habitats in human-dominated agricultural and suburban landscapes. However, their wildlife value and farmers’ willingness to maintain them for the conservation of regionally declining biodiversity are often both poorly documented. The objectives of this study of 61 dairy farm ponds located in Southern Quebec (Canada) were to (1) describe their biophysical features and birds’ use, (2) determine habitat and landscape characteristics that influence the bird community, and (3) assess the willingness of farmers to support wildlife use. The studied ponds were small (0.17 ha) and had rectangular shape with rocky/muddy steeply slopes (21°), surrounded by 3 m wide riparian strips and pastures, hayfields, and fallows. They were located about 300 m from farmhouses, buildings, streams, and adjacent ponds. A total of 1963 individuals belonging to 46 bird species were observed. The abundance of all bird species, of species with declining populations, and of crop damaging species were positively related to the area of fallow land and to the width of riparian strips; the areas of cereals and of mixed-wood forest had a negative influence. Only two habitat variables had influence on species richness: the width of riparian strips (+) and the distance to the closest farm buildings (–). Most pond landowners (>80%) were in favour of increasing wildlife use if they were given access to associated financial support and logistical assistance. Wider riparian strips and adjacent uncultivated field margins are recommended.

Bird Displacement by Wind Turbines: Assessing Current Knowledge and Recommendations for Future Studies

Wind energy developments can be responsible for negative impacts on birds, including displacement. In this study we performed a systematic review of the literature available on bird displacement due to wind turbines, both onshore and offshore, to: (i) assess overall trends in scientific research; (ii) review the existing knowledge; and (iii) outline recommendations for future studies on this topic in order to overcome the major gaps and limitations found. Our results are based on 286 trials extracted from 71 peer-reviewed studies. The literature on this topic has increased in the past decade but is concentrated in Europe and United States, despite the fact that the wind industry has worldwide coverage. Open habitats—as agricultural fields and grasslands—were the most represented and Accipitriformes, Galliformes, Charadriiformes, Anseriformes and Passeriformes were the most frequently studied taxa. Displacement was recorded in 40.6% of the trials, and Gaviiformes, Anseriformes, Suliformes, Accipitriformes and Falconiformes were the most affected groups. Pelecaniformes, Passeriformes and Charadriiformes were the groups for which no significant effects were more often observed. We provide a list of recommendations, focused on study design, reporting and result dissemination, that should contribute to more robust conclusions of future studies on this topic.

Ecology of Gamebirds in Namha National Protected Area, Lao People’s Democratic Republic

Using camera-trap data, we describe the ecology and occupancy of several species of gamebirds while assessing associations at Namha National Protected Area (Lao People’s Democratic Republic). We detected three species of Arborophila Partridges, albeit in low numbers. Red Junglefowl Gallus gallus show typical diurnal activity, and we provide a record of a male–female pair commensally associated with a boar Sus scrofa. Silver Pheasants Lophura nycthemera have sex ratios slightly favoring females, and are mostly solitary; we provide novel findings of male age structure and rectrix molt. Gray Peacock Pheasants Polyplectron bicalcaratum sex ratios also favor females; males are recorded displaying as early as late February, while daily activity is somewhat bimodal, and we provide novel findings of male age structure. Analysis of the association between occupancy and 14 environmental covariates indicated that Silver Pheasant and Gray Peacock-Pheasant were associated with rougher terrain, and Red Junglefowl had higher occupancy far from well-groomed trails used for tourism. We discuss our results by comparing and contrasting our findings with other studies, and consider implications for conservation in the region.

Nesting Success and Nesting Height in the Critically Endangered Medium Tree Finch (Camarhynchus pauper)

When different introduced species across trophic levels (parasite, predator) invade island systems, they may pose significant threats to nesting birds. In this study, we measure nesting height and infer causes of offspring mortality in the critically endangered Medium Tree Finch (Camarhynchus pauper), an island endemic restricted to Floreana Island on the Galápagos Archipelago. Considering all nests at which a male built a nest, sang and attempted to attract a female (n = 222 nests), only 10.4% of nests produced fledglings (5% of nests had total fledging success, 5.4% of nests had partial fledging success). Of the 123 nests chosen by a female, 18.7% produced fledglings and of 337 eggs laid, 13.4% produced fledglings. Pairing success was higher for older males, but male age did not predict nesting success. All nests with chicks were infested with avian vampire fly larvae (Philornis downsi). We attributed the cause of death to avian vampire fly if chicks were found dead in the nest with fly larvae or pupae (45%) present. We inferred avian (either Asio flammeus galapagoensis or Crotophaga ani) predation (24%) if the nest was empty but dishevelled; and black rat (Rattus rattus) predation (20%) if the nest was empty but undamaged. According to these criteria, the highest nests were depredated by avian predators, the lowest nests by rats, and intermediate nests failed because of avian vampire fly larvae. In conclusion, there is no safe nesting height on Floreana Island under current conditions of threats from two trophic levels (introduced parasitic dipteran, introduced mammalian/avian predators; with Galápagos Short-Eared Owls being the only native predator in the system).

Should Zoo Food Be Chopped for Captive Turacos?

It is common practice for keepers in zoological collections to provide animals in their care with food that is chopped into small pieces. Anecdotally, it has been suggested that chopped food reduces wastage and reduces aggression from group-housed animals. However, there is limited empirical evidence to support these suggestions. To investigate the effects of food condition (chopped or whole food), a study was undertaken on White-cheeked Turacos (Tauraco leucotis) and Fischer’s Turacos (Tauraco fischeri) at two zoological collections in the United Kingdom. This study investigated the effect of food condition on turaco behaviour, the amount of food eaten, and also the amount of time that keepers required to prepare the diet. There was no significant impact on the amount of food eaten as a result of providing whole food. For Fischer’s Turacos, the whole-food condition significantly increased the prevalence of feeding and foraging behaviour, whilst significantly reducing preening. For White-cheeked Turacos, only feeding and foraging was affected by food condition: no other behaviours were significantly affected by chopped or whole food. Keepers on average saved 151 s per meal when preparing whole-food diets. Overall, this study suggests that changing food presentation from chopped to whole has a limited impact on food intake and behaviour. Providing whole-food items may also save valuable keeper time. Future studies should investigate the impact of feeding whole-food items to a wider range of zoo-housed species.

Morph Composition Matters in the Gouldian Finch (Chloebia gouldiae): Involvement of Red-Headed Birds Increases Vigilance

Animals invest in costly vigilance to detect threats. Joining groups reduces these costs, which can be further reduced in mixed-species assemblages. In colour-polymorphic species, morphs often experience different predation pressure and vary in a variety of traits. However, little is known about differences in vigilance or how group composition affects vigilance. The aim was to investigate whether higher conspicuousness increased vigilance and whether vigilance was reduced in mixed-morph groups like in mixed-species assemblages. I tested vigilance in the colour-polymorphic Gouldian Finch (Chloebia gouldiae). Same sex pairs of different age and of either pure (red-red or black-black) or mixed head colour were exposed to three contexts (familiar, changed and novel environment) and head movements were recorded. All birds reduced the frequency of head movements with increasing novelty, indicating different vigilance strategies (switching from a searching to a tracking strategy) depending on the situation. While vigilance did not differ between morphs, morph composition mattered. Black-headed pairs made fewer head movements than mixed-head colour pairs. Results indicated that conspicuousness did not affect vigilance, possibly due to existing adaptations to reduce predation risk. However, whenever red-headed birds were involved, vigilance increased either because of higher group conspicuousness or prevalence of aggression.

Is “Fuel Reduction” Justified as Fire Management in Spotted Owl Habitat?

The California spotted owl is an imperiled species that selects mature conifer forests for nesting and roosting while actively foraging in the “snag forest habitat” created when fire or drought kills most of the trees in patches. Federal agencies believe there are excess surface fuels in both of these habitat conditions in many of California’s forests due to fuel accumulation from decades of fire suppression and recent drought-related tree mortality. Accordingly, agencies such as the U.S. Forest Service are implementing widespread logging in spotted owl territories. While they acknowledge habitat degradation from such logging, and risks to the conservation of declining spotted owl populations, agencies hypothesize that such active forest management equates to effective fuel reduction that is needed to curb fire severity for the overall benefit of this at-risk species. In an initial investigation, I analyzed this issue in a large 2020 fire, the Creek Fire (153,738 ha), in the southern Sierra Nevada mountains of California. I found that pre-fire snag density was not correlated with burn severity. I also found that more intensive forest management was correlated to higher fire severity. My results suggest the fuel reduction approach is not justified and provide indirect evidence that such management represents a threat to spotted owls.

Effects of Night Illumination on Behavior, Body Mass and Learning in Male Zebra Finches

An increase in artificial night lighting has blurred the boundaries of day and night and transformed the natural day-night environment with alteration in the temporal niche of the animals. Male zebra finches were exposed to a dim light at night (dLAN) protocol (Light: dLAN, 12L = 200 lux: 12dLAN = 5 lux) with controls on darkness at night (Light: dark, 12L = 200 lux: 12D = 0 lux) for six weeks. We assayed sleep-wake, daily behaviors, mood, and cognition, as well as changes in physiological parameters. Dim light at night increased sleep frequency, delayed sleep onset, advanced awakening latency, and caused a reduction in total sleep duration. dLAN birds did not associate (physical association) with novel object and birds spent significantly lesser time on perch with novel object as compared to LD. In colour learning task, night illuminated birds took more time to learn and made more error, compared to LD. dLAN significantly altered the 24-h daily behavioral rhythm (amplitude and acrophase) of feeding, drinking, preening, and perch-hopping behavior. In particular, birds extended their feeding hours in the nighttime under dLAN, with no difference in total food intake. Birds under dLAN increased fattening and hence significantly increased body mass. Our results show that dim light at night altered feeding rhythm, caused decrease in sleep behavior, and negatively affected learning and memory performance in male zebra finches.