Ornithology Research Questions

Annotation: A time-activity budget is a quantitative estimate of the proportion of time spent in specific behaviours such as foraging, grooming, resting, vigilance, seeking mates and more. Time-activity budgets vary across species, habitats, and seasons. Different habitat characteristics (often resulting from different human land-use) can significantly alter food availability and habitat features. When food is abundant, birds may spend less time searching for food and extra time can be devoted to other behaviours. During food scarcity, birds could spend more time searching for food, potentially decreasing time available for grooming, social interactions, and vigilance. Similarly, disturbance, predator density, availability of nesting sites are expected to alter time-activity budgets. Because the breakup of how birds allocate their time can affect survival and reproduction, it is important to study how these vary across land-use gradients

Annotation: Song is a highly evolved acoustic signal used to communicate individual identity, territory ownership, and reproductive capabilities. Its structure varies as a result of various evolutionary processes. Documenting variation in birdsong is an important step toward revealing the evolution of reproductive isolation over evolutionary time scales, which may eventually lead to population divergence and even speciation. Geographical variation in song is known in species with disjunct distributions, but is also observed in some species that have a continuous distribution. Widely distributed species of robins, prinias, and whistling-thrushes may be good models for understanding variation in birdsong and its underlying causes.

Annotation: Given recent evidence that female song is ancestral and widespread in songbirds, we must reevaluate the assumption that bird song functions primarily in female choice or male-male competition. This calls for a large-scale evaluation of the function and complexity of female bird song through comparative studies across species, and for an examination of the differences in structure and function of song between sexes within a species. Indian birds provide an opportunity to understand the factors that may have driven the maintenance or loss of song in female birds.

Annotation: Migratory birds share space and other resources with resident species when they travel to their migratory grounds. It is likely that resident and migratory birds partition resources (use different resources like different foraging habits, different feeding heights) to avoid competition. However, the extent and consequences of competition between migratory and resident birds has not been studied.

Annotation: The sustenance and survival of any species depends on successful foraging and breeding in its environment. A problem arises when the landscape changes rapidly as a result of anthropogenic activities or natural disasters. In such cases, individuals may either shift to a more favourable landscape or habitat nearby, or change their behaviour as the situation demands (i.e., by showing behavioural plasticity). To understand what enables the persistence of avifauna in a changing landscape, it is necessary to study a species' behavioural changes in foraging (i.e., food selection) and breeding (i.e., nest site selection, nesting material, and nest architecture). Suitable model species for such studies are common and widespread species like bulbuls, mynas, swallows, and munias.

Annotation: Artificial light at night is an increasingly important feature of urban habitats. Such light may change activity patterns of both diurnal and nocturnal birds. As cities expand, it is important to study how night lights affect bird behaviour. For example, how do diurnal birds change their activity budgets in response to night lights, and how does that in turn change their foraging and reproductive success? In addition, the costs and benefits of artificial night lights to nocturnal birds also remain to be understood.

Annotation: When animals communicate using sound in noisy environments (background noise from other calling animals, wind, water or traffic), their sounds overlap with those from the background, resulting in masking. Masking is a serious problem because it makes it harder for receivers to extract meaningful sounds from irrelevant noise. Birds may respond to masking using a variety of strategies, including increasing signal amplitude (i.e., vocalise loudly) and frequency, using more pure tones, and shifting song to times of less noise, such as to the night. Understanding how birds overcome masking will help understand how acoustic niches are partitioned and may generate ideas for signal discrimination for human applications. It is also important to understand how bird vocalisations are affected by anthropogenic noise, for example in urban environments.

Annotation: At a community level, biotic processes like competition and predation are thought to structure bird communities. At larger scales, climate and geography influence the broad assemblage of species in a region. While the role of biotic processes and of environmental factors are typically studied separately, rapid global land use and climate change mean that there is a need to examine both sets of interactions at a large spatial scale, and across multiple locations.

Annotation: Land-use change is one of the major drivers of biodiversity loss. It can involve largescale change in habitats as well as fragmentation. It is critical to understand the impacts of land-use change on different habitats (e.g. forests, open natural ecosystems) and bird guilds (e.g. feeding, nesting, habitat). Which are the most harmful changes, and which are relatively benign? What are its effects on habitat specialist/sensitive species, and how can these effects be mitigated? These questions are particularly urgent to answer in habitats that are presently undergoing rapid change and fragmentation—for example grasslands.

Annotation: Urbanisation results in increased human infrastructure and modified environmental conditions (e.g., light and noise pollution). Natural habitats are typically reduced, fragmented, and highly manicured, becoming unsuitable for many bird species, particularly habitat specialists. Given the high rates of urbanisation, it is critical to determine how urbanisation can be planned to maintain taxonomic and functional diversity of birds.

Annotation: Plant species are introduced intentionally or inadvertently in different habitats (e.g., forest plantations, ornamental/avenue trees in urban areas). Some of these species can become invasive. As exotic plants invade new habitats, they might alter habitat structure and resource (fruits, flowers/nectar, nesting) availability for native bird communities. What are the impacts of such plants on the behaviour, demography, population dynamics, and community traits of birds?

Annotation: Negative interactions between invasive plant species and bird communities have received some research attention. However, in some situations, invasive plants and native birds may benefit from each other. For example, there appears to be a mutualistic relationship between Lantana and many frugivorous birds, which might lead to the ironic outcome of native species facilitating the spread of invasives, thereby altering habitat structure and composition, and changing resource availability for other native species. How do these effects occur, under what circumstances, and with what outcomes?

Annotation: Open Natural Ecosystems or ONEs (such as deserts, grasslands and shrublands) are understudied in India. They are historically neglected in Government policy, often labelled as ‘wastelands’, and earmarked to be made more ‘productive’. As a result, these are among the most heavily modified and therefore threatened ecosystems in India. Studies are needed to understand how birds of ONEs are affected by human activities, including grazing livestock, fire, infrastructure like windmills and powerlines, and land conversion and fragmentation.

Annotation: Agricultural practices encompass various types of farming at different intensities. Agricultural intensification is a multi-faceted process for achieving increased yields (agricultural production per unit area). It usually involves increase in agricultural inputs and changes in farming practices that lead to conversion of natural habitat to cropland, fragmentation of natural habitat, changes in crop types and cycles, reduction in the extent and duration of fallows, and reduction in habitat heterogeneity at multiple spatial scales. While considerable research has been done globally, and a few Indian studies exist as well, the extent and consequences of agriculture require much more research in India. These could address the impacts of intensification of farming on bird diversity (including taxonomic, functional and phylogenetic diversity) at different spatial and temporal scales, and an exploration of different scenarios under which agricultural production and bird conservation can co-exist.

Annotation: Changes in irrigation influence hydrology and land-use in arid and semi-arid regions through increases of land area under agriculture, alteration of water levels, afforestation along the irrigation channel network, introduction of invasive plant species, and development of seepage wetlands. How do these changes impact the composition, richness, and abundances of birds at different spatial scales? How do habitat specialists, such as certain farmland birds, birds of arid or semi-arid regions (e.g. bustards), wetland birds and also ‘common’ species, respond to changes driven by irrigation? Although some work has been done to address these questions, the immense scale of the transformation calls for further research across a variety of landscapes.

Annotation: Recent research in urban areas has shown that cities around the world are occupied by species with similar ecology. Habitat and diet generalists, cavity nesters and flocking species are more common in urban areas than in other habitats, a phenomenon called biotic homogenization. Yet we do not fully understand why this pattern arises repeatedly: why habitat specialists, or open cup nesters, for example, are at a disadvantage in cities. Citizen science provides an opportunity to first assess the broad patterns in India. Subsequent research across a rural-urban gradient will be key to understanding why and how biotic homogenization occurs.

Annotation: The number and types of species vary along environmental gradients such as temperature, precipitation, humidity, and so on. In addition there are variations in traits (such as wing size, bill size, bill type, egg laying pattern, egg size, egg colour, and song) and behaviour both across and within species. For example, the Singing Bushlark Mirafra javanica in Africa does not mimic, unlike its Indian counterparts; and Jungle Myna eye colour is golden in its northern populations versus whitish in the peninsula. What is the functional significance of such trait variation, how do traits relate to ecology and environment, and how is this reflected in species distributions?

Annotation: Animal-pollinated flowers can be ordered along a spectrum with respect to birds: at the one extreme, some may not be visited by birds at all, while others (termed ornithophilous plants) may receive considerable bird visitation. There are very few bird-specialist flowers; most ornithophilous plants are visited by multiple species of flower visitors, which may include birds, bats and insects. Given that all flower visitors may not contribute equally to pollination, what is the relative contribution of bird visitors to pollination and seed-set across different types of flowers?

Annotation: Birds may act as biological pest control agents in various ways, but much more work on the context and magnitude of these effects is needed. For example, it is widely believed that insectivorous birds are beneficial in controlling crop pests. However, in some situations, insectivorous birds may be a mixed blessing, as they tend to be generalists, and therefore may feed on not just pests but also species like parasitoids and predators (e.g., spiders) that themselves control pests. Similarly, research in other countries suggests that raptors can control or deter rodents in farms, but they may simultaneously deter beneficial insectivorous birds. If birds do indeed control pests, then under what conditions does this occur: which crops are such effects seen in, and does this happen only under certain conditions of habitat matrix (e.g. surrounded by natural habitats) or management practices (e.g. availability of perches)? In addition to conducting broad-scale comparative studies, targeted research is also needed to quantify the impact of a particular predatory species against a specific pest in a specific crop. Results of this kind of research would be of broad applicability in integrated pest management and in conservation.

Annotation: Different species of birds (and perhaps even the same species) might provide both positive services (like pollination and pest control) as well as disservices (like crop damage). Farm management strategies like cropping patterns, retaining semi-natural habitat in and around fields, and artificial or natural perches can help attract certain species by providing suitable conditions for birds. On the other hand, various visual, auditory, tactile, exclusion and olfactory deterrents are used to keep harmful birds away. How can farmers manage the tradeoff between these opposing intentions such that benefits are maximised? This will need to be tested observationally and experimentally in a number of site- and context-specific studies.

Annotation: Ecosystem processes are critical for maintenance of biodiversity and for providing services to humans. Birds provide key ecosystem functions, like pollination and seed dispersal, but it is not clear how resilient these functions are in the face of anthropogenic change. With land-use change and habitat fragmentation being key threats to natural ecosystems, it is vital to understand how these processes affect the ecosystem functions fulfilled by birds.

Annotation: Bird collisions with civilian and military aircraft are a global problem. In India, the Directorate General of Civil Aviation (DGCA) issued a circular in August 2022 titled “Management of potential wildlife hazards at licensed aerodromes”. This circular acknowledges the severity of the problem and highlights the urgency to deal with the hazard. Research is needed to understand how flight schedules and type of aircraft intersect with species size, behaviour, and density to affect collision risk, and how this is affected by the features of the surrounding landscape. Research is needed to suggest suitable management options in different situations, and then to monitor and evaluate their efficacy once implemented. With more aircraft in the skies every year, this is a vital direction for investigation.

Annotation: The impacts of free-ranging dogs and cats on birds and other wildlife appear to be increasing over time, but in India the matter has not received the research attention it deserves. Consequently, we have no rigorous estimates of the magnitude of the problem (e.g., number of birds killed), nor what might underlie variation in these impacts, let alone what options are available for effective mitigation in different types of habitats including cities, towns, villages and agricultural landscapes. The answers to these questions are needed if India is to devise sensible policies related to free-ranging dogs and cats, which take into account conservation needs as well.

Annotation: Traditionally, carcasses of cows or other livestock have been disposed of in the open, to be fed upon by natural scavengers. This practice appears to have reduced in recent years, with carcasses increasingly being buried rather than discarded in the open, possibly in response to decreasing vulture populations. What are the consequences of these changes for vultures and other scavenging raptors? This group of birds has experienced particularly heavy decline in the past couple of decades, and any recovery may well be dependent on the availability of food.

Annotation: Tourism in India is increasingly linked to nature. While this is a welcome development, rising tourism demands better infrastructure (e.g., roads, hotels, electricity), and resources (e.g., water and fuel, including fuelwood). These demands increase the pressure on natural habitats, potentially affecting bird populations. Vehicles and people can generate disturbances that affect the behaviour of birds. Photography and associated tools (e.g., song playback, hides, feeders) may have additional effects. How all these effects act individually and in combination to impact bird behaviour, food availability, breeding, and populations is a topic of urgent research.

Annotation: Birds use song and calls to communicate with each other, and playback of recorded audio is commonly used in ecotourism to bring birds into the open for better views by birdwatchers and photographers. Playback is also used in research to investigate the function of different sounds, and as an assay in population monitoring of pheasants and owls. Playback for ecotourism has been criticised, but the actual short- and long-term impacts on behaviour and population dynamics are poorly understood. This calls for careful research on estimating the magnitude and context of possible negative effects.

Annotation: Indigenous knowledge about birds is encapsulated in various forms that are passed down the generations, including art, song and folklore. Documenting and compiling this knowledge ensures that it can pass to future generations of the same community as well as the larger citizenry. Indigenous knowledge can be used as a springboard for better understanding the natural history of various species as well as to generate ideas for how to more meaningfully understand human-nature relationships, and their implications for conservation.

Annotation: There is growing global concern regarding the loss of nesting spaces for birds that nest in trees and other cavities. In India, over 200 species are known to use tree cavities. Providing artificial nest boxes can be an effective means to improve the population status of such species, especially in agriculture and urban landscapes, and a number of efforts are underway to make and install nest-boxes across India. However, the long-term efficacy of artificial nest boxes in improving nesting rates and outcomes, and thereby the population status of species, is poorly understood and requires research attention.