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Expansion of anthropogenic noise and night lighting across our planet 1 , 2 is of increasing conservation concern 3 – 6 . Despite growing knowledge of physiological and behavioural responses to these stimuli from single-species and local-scale studies, whether these pollutants affect fitness is less clear, as is how and why species vary in their sensitivity to these anthropic stressors. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. For example, overall nest success was negatively correlated with noise among birds in closed environments. Species-specific changes in reproductive timing and hatching success in response to noise exposure were explained by vocalization frequency, nesting location and diet. Additionally, increased light-gathering ability of species’ eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches 7 . Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation. Human-generated noise and night lighting affect breeding habits and fitness in birds, implying that sensory pollutants must be considered alongside other environmental factors in assessing biodiversity conservation.

Parental care is essential for the survival of mammals, yet the mechanisms underlying its evolution remain largely unknown. Here we show that two sister species of mice, Peromyscus polionotus and Peromyscus maniculatus , have large and heritable differences in parental behaviour. Using quantitative genetics, we identify 12 genomic regions that affect parental care, 8 of which have sex-specific effects, suggesting that parental care can evolve independently in males and females. Furthermore, some regions affect parental care broadly, whereas others affect specific behaviours, such as nest building. Of the genes linked to differences in nest-building behaviour, vasopressin is differentially expressed in the hypothalamus of the two species, with increased levels associated with less nest building. Using pharmacology in Peromyscus and chemogenetics in Mus , we show that vasopressin inhibits nest building but not other parental behaviours. Together, our results indicate that variation in an ancient neuropeptide contributes to interspecific differences in parental care. Parental care in mice evolves through multiple genetic changes; one candidate is vasopressin, the reduced expression of which promotes parental nest-building behaviour in monogamous mice. Genetics of parental care Rodents display a wide range of parental care behaviours, such as nest building, with some species more driven to perform these duties than others. However, the genetic and evolutionary mechanisms that influence the extent to which parental care behaviours are performed have remained unknown. Here, Hopi Hoekstra and colleagues utilize a quantitative genetic approach to identify genetic candidates that influence parental care in closely related mouse species. Genetic changes that enhance the levels of the hypothalamic hormone vasopressin were linked to less nest building. In addition, artificial manipulation of neurons releasing vasopressin could directly affect the extent of nest building, with lower vasopressin-releasing neuronal activity correlated with increased levels of nest building. This suggests that variation in neuropeptide signalling may contribute to complex social behaviours such as parental care.

Neonicotinoid pesticides cause mortality and decline in insect pollinators. One repeatedly noted effect is a reduction in bee colony size. However, the mechanism behind this reduction is unclear. Crall et al. performed complex real-time monitoring of bumblebee behavior within their nests (see the Perspective by Raine). Neonicotinoid exposure reduced nurse and caretaking behaviors, which affected productivity and harmed colony thermoregulation. These changes in behavior acted together to decrease colony viability, even when exposure was nonlethal. Science , this issue p. 683 ; see also p. 643 Neonicotinoid insecticides disrupt worker-bee caretaking behavior within bumblebee colonies. Neonicotinoid pesticides can negatively affect bee colonies, but the behavioral mechanisms by which these compounds impair colony growth remain unclear. Here, we investigate imidacloprid’s effects on bumblebee worker behavior within the nest, using an automated, robotic platform for continuous, multicolony monitoring of uniquely identified workers. We find that exposure to field-realistic levels of imidacloprid impairs nursing and alters social and spatial dynamics within nests, but that these effects vary substantially with time of day. In the field, imidacloprid impairs colony thermoregulation, including the construction of an insulating wax canopy. Our results show that neonicotinoids induce widespread disruption of within-nest worker behavior that may contribute to impaired growth, highlighting the potential of automated techniques for characterizing the multifaceted, dynamic impacts of stressors on behavior in bee colonies.

We investigated the impact of two natural pulses (food and nesting resources) on intra- and inter-specific territorial behaviour of species that co-occur year-round in multi-species groups. We simulated conspecific and heterospecific territorial intrusions in two cavity-nesting species using 974 model presentations with territorial song playbacks during and after a dual resource pulse of insect (bark beetle) prey and nest cavities across 5 years in British Columbia, Canada. As beetle abundance increased, both species increased aggression toward conspecific intruders. At peak beetle abundance the (typically) subordinate generalist insectivore, mountain chickadee ( Poecile gambeli ), attacked model intruders more frequently than did the dominant bark insectivore, red-breasted nuthatch ( Sitta canadensis ), and responded more aggressively to nuthatch intruders than to conspecifics. The reversal in the inter-specific dominance hierarchy suggests that behavioural mechanisms governing community structure may change during resource pulses. Overall, we suggest that social interactions between chickadees and nuthatches are dynamic with high complexity and flexibility to major ecological changes. Future work that examines the fitness consequences of temporal variation in community dynamics and resiliency could help to reveal evolutionary mechanisms by which these species co-exist.

Hornets (genus Vespa ) are a conspicuous taxon of large eusocial wasps that are predators of other insects. Increasingly, hornets are gaining notoriety as damaging invaders after repeated introductions into novel habitats. Most hornets are highly effective predators, so they have the potential to greatly impact local entomofauna, including economically important pollinators. In 2016, Vespa tropica , a hornet with a broad natural range throughout subtropical and tropical Asia, was detected on Guam, although few details have been published since the initial alert. We provide the first comprehensive update on the status and impact of V. tropica hornets on Guam based on nine years of beekeeper and public reports, as well as field collections of nests, hornets, and videos of hunting behavior in managed apiaries. We show that the population of non-native V. tropica is established and thriving on Guam. Nests were found in a diversity of sites: below and above ground, sheltered and exposed, and in urban and greenspaces. V. tropica was a year-round predator in apiaries, with up to 12% of colony losses per year attributed to hornet attacks. Notably, hornets often attacked single honey bee ( Apis mellifera ) colonies in groups, similar to the hunting strategy of their close relatives, the giant hornets Vespa mandarinia and Vespa soror . Hornets killed defending workers, eventually weakening colonies and entering hives to consume bee brood. Bees mounted defenses that included alarm piping, bee ‘carpets’, and attempts to ball hornets. Hornets were active all year, but were significantly more active during the wet season (July‒December). Preliminary analysis of color forms suggested that the source of V. tropica on Guam is likely continental southeast Asia, although genetic analyses are required. Our study reveals that Guam is facing a fierce invader in V. tropica , which is placing strong predatory pressure on pre-established honey bees.

Presence-absence surveys are frequently used to monitor populations of rare and elusive species. Such data may also be used as a proxy for breeding activity, but links between presence-absence data and higher-order processes must be validated to determine their reliability. The Marbled Murrelet ( Brachyramphus marmoratus ) is a threatened seabird that nests in older-aged forests along the Pacific Coast. Its nests are exceptionally difficult to find, so we tested whether presence-absence surveys can help identify nesting sites. Between 2018 and 2022 we located 17 trees containing active murrelet nests in the Oregon Coast Range (USA) and 38 trees that purportedly contained no active nests (26 in occupied murrelet stands and 12 in unoccupied stands). Observers surveyed within 200 m of focal trees using standard presence-absence surveys, and we modeled the effects of site status (active nest or control) and distance from the focal tree on probability of recording murrelets. We never detected murrelets in unoccupied control sites. We found some evidence that the probability of recording presence was higher at active nesting sites (0.81, 95% CI: 0.71, 0.88) than at occupied control sites (0.71, 95% CI: 0.64, 0.78) although a null model had similar support. The probability of recording murrelet breeding behaviors in nesting and occupied control sites was 0.20 (95% CI: 0.14, 0.27) regardless of distance to a known active nest. These results suggest that presence-absence surveys may be useful for identifying plausible murrelet nesting habitat, but they are ineffective for identifying active nesting sites. Moreover, we estimated that 20 repeated surveys at a point in space are required to reasonably conclude there are no active nesting sites within 200 m. These findings serve as an important reminder of the limitations that can come with relying on presence-absence data alone to identify breeding sites.

Among the diverse sexual signals used by birds, the possible signaling functions of non-bodily objects during mating/courting displays remain unexplained. It is unclear whether such object-holding gestures are purely ritualistic or serve as an advertisement of an extended phenotype to potential mates. Estrildid finches (family Estrildidae) are characterized by mutual courtship, during which either a male or female will hold nesting material (usually grass stems or straw) in the beak while singing and dancing toward the opposite sex. We predicted that this display of potential nesting material advertises the ability of an individual to collect and transport such materials. Captive adult red-cheeked cordon-bleus ( Uraeginthus bengalus ) and star finches ( Neochmia ruficauda ) were presented with different string lengths in choice tests, and results were compared with those obtained from field observations of courtship displays among U. bengalus and blue-capped cordon-bleus ( Uraeginthus cyanocephalus ). Both captive and wild estrildid finches preferred longer strings for displays, which is compatible with the idea that non-bodily ornaments (strings) convey information on the maximum performance potential. The evolution of nesting material holding displays is likely associated with the nesting ecology of estrildid finches, which is characterized by a high predation risk and joint nest building by mating pairs.

Birds and their nests are vulnerable to predation during the breeding season. Many birds have evolved nest placement strategies that minimize risk such as concealing nests in vegetation, or nesting in inaccessible cavities or on cliffs. Some ground-nesting species choose open areas where vegetative concealment or physical protection is minimal. These species may benefit from the ability to visually detect predators approaching the nest, affording them more time to perform evasive or distracting behaviors. We studied the nesting behavior of piping plovers ( Charadrius melodus ) on Fire Island, New York from 2015–2020 to determine if the area visible from the nest (i.e., ‘viewshed’) affected nest site selection. We calculated viewsheds at nests and random points and evaluated nest site selection using logistic regression modelling. Piping plovers selected nest sites with a greater view of predators than would be expected if nest site selection was random relative to viewshed. The inclusion of viewshed improved the predictive ability of a previous nest site selection model that was based on habitat characteristics present on the landscape in 2015, but its influence weakened as ecological succession progressed. Topographic variation was the predominant visual obstruction source at plover nest sites compared to vegetation height. Viewshed may play a role in nest site selection in other ground-nesting birds, and thus is an important factor to consider in the development of habitat management strategies and in understanding the evolution of behavior.

Classifying animal behaviors in their natural environments is both challenging and ecologically important, but the use of biologgers with multiple sensors has significantly advanced this research beyond the capabilities of traditional methods alone. Here, we show how biologgers containing an integrated tri-axial accelerometer, GPS logger and immersion sensor were used to infer behavioural states of a cryptic, freshwater turtle, the Blanding’s turtle ( Emydoidea blandingii ). Biologgers were attached to three males and five females that reside in two undisturbed coastal marshes in northeastern Georgian Bay (Ontario, Canada) between May and July 2023. Raw acceleration values were separated into static and dynamic acceleration and subsequently used to calculate overall dynamic body acceleration (ODBA) and pitch. The unsupervised Hidden Markov Model (HMM) successfully differentiated five behavioural states as follows: active in water, resting in water, active out of water, resting in water, and nesting. Overall accuracy of the classification was 93.8%, and except for nesting (79%), all other behaviours were above 92%. There were significant differences in daily activity budgets between male and female turtles, with females spending a greater proportion of time active out of water, and inactive out of the water, while males spent a greater proportion of time active in water. These differences were likely a result of large seasonal life-history requirements such as nesting and mate finding. Accurate classification of behavioural states is important for researchers to understand fine-scale activities carried out during the active season and how environmental variables may influence the behaviours of turtles in their natural habitats.

Coastal habitats play an important role in the nesting ecology of shorebirds; however, these habitats are increasingly threatened by human activity and ongoing habitat loss. The conservation of shorebird populations thus necessitates understanding the utilization pattern of artificial coastal habitats by these birds. Substrate particle size and vegetation cover are key environmental factors influencing the nest site selection and nest success in ground-nesting shorebirds such as plovers. This study aimed to investigate the impact of substrate particle size and vegetation cover for the Kentish plover ( Anarhynchus alexandrinus ) nesting sites within an artificial coastal environment, the Saemangeum reclaimed land. Geological criteria and 1-m 2 quadrat photos were used to develop Bayesian network (BN) models to analyze the impact of these variables on nest site selection and nest success in 2020. The BN models predicted the impact of substrate particle size and vegetation cover on the likelihood of nest presence and nest success. The results indicated that Kentish plovers prefer sandy sites with moderate vegetation cover and achieve higher nest success in habitats with mixed soil types, including medium (0.25–0.5 mm), fine (0.125–0.25 mm), and very fine (0.063–0.125 mm) sand, along with small proportions of mud (<0.063 mm). These findings highlight the importance of evaluating the complex interactions between plover nests and substrate characteristics, including soil porosity and permeability. Vegetation cover must also be managed with attention to the trade-offs involved, such as predation risk, nest camouflage, crypsis, and thermoregulation which influence plover nesting preference and success. This study provides valuable quantitative insights and emphasizes the need for incorporating multi-layered ecological factors along with inherent uncertainties in coastal environments to restore appropriate artificial coastal habitats for shorebird conservation.