Grant Ballard

• PhD Biological Sciences
• Chief Science Officer at Point Blue Conservation Science

The current highly pathogenic avian influenza H5N1 panzootic is having substantial impacts on wild birds and marine mammals. Following major and widespread outbreaks in South America, an incursion to Antarctica occurred late in the austral summer of 2023/2024 and was confined to the region of the Antarctic Peninsula. To infer potential underlying p...

To fulfill their conservation potential and provide safeguards for biodiversity, marine protected areas (MPAs) need coordinated research and monitoring for informed management through effective evaluation of ecosystem dynamics. However, coordination is challenging, often due to knowledge gaps caused by inadequate access to data and resources, compo...

According to the ‘selfish herd’ hypothesis, most seabird species breed colonially so that individuals can decrease their risk of predation by forming compact groups. However, costs and benefits associated with colonial breeding may not be evenly distributed among individuals within a colony. At Adélie penguin colonies, individuals nesting on the pe...

Sex‐related differences in vital rates that drive population change reflect the basic life history of a species. However, for visually monomorphic bird species, determining the effect of sex on demographics can be a challenge. In this study, we investigated the effect of sex on apparent survival, recruitment, and breeding propensity in the Adélie p...

Seasonal migration, driven by shifts in annual climate cycles and resources, is a key part of the life history and ecology of species across taxonomic groups. By influencing the amount of energy needed to move, external forces such as wind and ocean currents are often key drivers of migratory pathways exposing individuals to varying resources, envi...

Unlike in many polar regions, the spatial extent and duration of the sea ice season have increased in the Ross Sea sector of the Southern Ocean during the satellite era. Simultaneously, populations of Adélie penguins, a sea ice obligate, have been stable or increasing in the region. Relationships between Adélie penguin population growth and sea ice...

The current highly pathogenic avian influenza H5N1 panzootic has profound impacts on wild birds. Herein, we compiled H5N1 surveillance from Antarctica and Sub-Antarctic Islands to ascertain whether HPAI was present in this region. Observations and HPAI testing indicated no incursion of the virus during the austral summer 2022/23.

South polar skuas migrate from subtropical regions to breed along coastal Antarctica. In a fecal sample collected on Ross Island, Antarctica, we identified 20 diverse microviruses (Microviridae) that share low levels of similarity to currently known microviruses; 6 appear to use a Mycoplasma/Spiroplasma codon translation table.

Age-related variation in foraging performance can result from both within-individual change and selection processes. These mechanisms can only be disentangled by using logistically challenging long-term, longitudinal studies. Coupling a long-term demographic data set with high-temporal-resolution tracking of 18 Adélie penguins (Pygoscelis adeliae,...

We conducted the first assessment of Adélie Penguin (Pygoscelis adeliae) chick survival that accounts for imperfect resighting. We found that when chicks are larger in size when they enter the crèche stage (the period when both parents forage at the same time and chicks are left relatively unprotected), they have a higher probability of survival to...

Autonomous survey and aerial photogrammetry applications require solving a path planning problem that ensures sensor coverage over a specified area. In this work, we provide a multi-robot path planning method that can obtain this coverage over an arbitrary area of interest. We extend our previous method, path optimization for population counting wi...

When provisioning chicks, parents trade-off their time, energy, and other resources to maximize reproductive success. As parents adjust investment to maximize their fitness, impacts on offspring growth can occur. We investigated provisioning and chick growth of Adlie Penguins (Pygoscelis adeliae) at one of the largest colonies (175,000 pairs), duri...

Quantifying food intake in wild animals is crucial to many ecological and evolutionary questions, yet it can be very challenging, especially in the marine environment. Because foraging behavior can be inferred from dive recordings in many marine creatures, we hypothesized that specific behavioral dive variables can indicate food intake. To test thi...

In colonial seabirds, differences in the nesting or fledging success have been associated with differences in nest position within the breeding aggregation (subcolony): less successful nests are located on the periphery, with more successful nests closer to the center. For Pygoscelid penguins, central nests tend to be larger, with nest size being a...

Group-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic paramete...

Plumage colour variation occurs widely among bird species and is often associated with individual fitness. More specifically, colouration can affect thermoregulatory ability, mate selection and conspicuousness during foraging. Colour aberrations can be caused by genetic mutations, dietary imbalances, environmental conditions or disease and are rare...

Age‐related variation in reproductive performance in long‐lived iteroparous vertebrate species is common, with performance being influenced by within‐individual processes, such as improvement and senescence, in combination with among‐individual processes, such as selective appearance and disappearance. Few studies of age‐related reproductive perfor...

Speed is essential in wildlife surveys due to the dynamic movement of animals throughout their environment and potentially extreme changes in weather. In this work, we present a multirobot path-planning method for conducting aerial surveys over large areas designed to make the best use of limited flight time. Unlike current survey path-planning sol...

Evidence indicates that Antarctic minke whales (AMWs) in the Ross Sea affect the foraging behaviour, especially diet, of sympatric Adélie penguins (ADPEs) by, we hypothesize, influencing the availability of prey they have in common, mainly crystal krill. To further investigate this interaction, we undertook a study in McMurdo Sound during 2012-2013...

Intraspecific competition for food can be especially high in colonial breeding seabirds. To minimize colony-induced or annual foraging challenges, diet may vary among individuals, but few studies have simultaneously investigated the effects of both extrinsic conditions (e.g. colony or year effects) and parameters of an individual (e.g. sex, age, or...

Predators impact preyscapes (3-D distribution of forage species) by consuming prey according to their abilities or by altering prey behavior as they avoid being consumed. We elucidate prey (Antarctic silverfish[Pleuragramma antarctica] and crystal krill[Euphausia chrystallorophias]) responses to predation associated with the marginal ice zone (MIZ)...

Southern Ocean ecosystems are under pressure from resource exploitation and climate change1,2. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally...

The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...

The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...

Emperor penguins require stable fast ice, sea ice anchored to land or ice shelves, on which to lay eggs and raise chicks. As the climate warms, changes in sea ice are expected to lead to substantial declines at many emperor penguin colonies. The most southerly colonies have been predicted to remain buffered from the direct impacts of warming for mu...

Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior...

Understanding the causes of disease in Antarctic wildlife is crucial, as many of these species are already threatened by environmental changes brought about by climate change. In recent years, Antarctic penguins have been showing signs of an unknown pathology: a feather disorder characterised by missing feathers, resulting in exposed skin. During t...

Adélie penguins are renowned for their natal philopatry on land-based colonies, requiring small pebbles to be used for nests. We report on an opportunistic observation via aerial survey, where hundreds of Adélie penguins were documented displaying nesting behaviours on fast ice ~3 km off the coast of Cape Crozier, which is one of the largest coloni...

Age variation in reproductive performance is well-documented but the mechanisms underlying this variation remain unclear. Foraging efficiency is likely to be a key source of demographic variation as it determines the amount of energy that can be invested in fitness-related activities. Evidence of age-related changes in the foraging efficiency of ad...

In 2017/18, we recorded multiple instances of Adelie Penguin Pygoscelis adeliae nests containing three chicks at Cape Crozier, Ross Island, Antarctica. In one sub-colony, 0.67 % of nests had three chicks, or two chicks and one egg. We found that some Adelie Penguin pairs were willing to brood three chicks, as well as chicks that were not their own....

According to central place foraging theory, breeding seabirds should energetically optimize prey acquisition and, therefore, foraging is expected to be located where prey are most available, within limits defined by the energetics of the species. We have shown this previously for Adélie penguins Pygoscelis adeliae, using foraging intensity as a pro...

We assessed whether the mass of Adélie penguin Pygoscelis adeliae fledglings at 3 colonies of markedly disparate size on Ross Island, Ross Sea, correlated with their eventual return as subadults. We compared our results with those from Anvers Island, Bellingshausen Sea. Colony sizes at Ross Island have been increasing, contrary to decreasing size a...

Reproductive timing in many taxa plays a key role in determining breeding productivity ¹, and is often sensitive to climatic conditions ² . Current climate change may alter the timing of breeding at different rates across trophic levels, potentially resulting in temporal mismatch between the resource requirements of predators and their prey ³ . Thi...

Evaluating the fitness of organisms is an essential step towards understanding their responses to environmental change. Connections between energy expenditure and fitness have been postulated for nearly a century. However, testing this premise among wild animals is constrained by difficulties in measuring energy expenditure while simultaneously mon...

The family Papillomaviridae contains more than 320 papillomavirus types, with most having been identified as infecting skin and mucosal epithelium in mammalian hosts. To date, only nine non-mammalian papillomaviruses have been described from birds (n = 5), a fish (n = 1), a snake (n = 1), and turtles (n = 2). The identification of papillomaviruses...

The Ross Sea pelagic food web is closely coupled, with the foraging among abundant upper level species affecting the foraging of one another. To investigate the roles cetaceans may have in such interspecific interactions in this system, we studied within-season and interannual occurrence patterns of Antarctic minke whales (Balaenoptera bonaerensis)...

The viruses circulating among Antarctic wildlife remain largely unknown. In an effort to identify viruses associated with Weddell seals (Leptonychotes weddellii) inhabiting the Ross Sea, vaginal and nasal swabs, and faecal samples were collected between November 2014 and February 2015. In addition, a Weddell seal kidney and South Polar skua (Sterco...

Evidence of climate change-driven shifts in plant and animal phenology have raised concerns that certain trophic interactions may be increasingly mismatched in time, resulting in declines in reproductive success. Given the constraints imposed by extreme seasonality at high latitudes and the rapid shifts in phenology seen in the Arctic, we would als...

We comment on the conjecture by Parker et al . (2016) that Antarctic toothfish recently returned to McMurdo Sound, arguing that this species never departed. Instead, as deduced from a 40-year fishing effort, toothfish water column prevalence became markedly reduced where bottom depths are <500 m, with research continuing to show their presence on t...

Extraction of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea began in 1997, following a management plan that targets the largest fish with a goal of reducing the spawning biomass by 50% over 35 years. We investigate the potential long-term consequences of the reduced availability of this prey for Weddell seals (Leptonychotes weddellii)....

Sexually size-dimorphic species must show some difference between the sexes in growth rate and/or length of growing period. Such differences in growth parameters can cause the sexes to be impacted by environmental variability in different ways, and understanding these differences allows a better understanding of patterns in productivity between ind...

We investigated mesopredator effects on prey availability in the Ross Sea, Antarctica, as - sessing the reasons why Adélie penguin Pygoscelis adeliae foraging trip duration (FTD) increases and diet changes from krill to fish as numbers of foraging penguins and competing cetaceans increase in the penguins' foraging area. To investigate penguins' sea...

Introduction to the Midwest Avian Data Center which is part of the Avian Knowledge Network. More info at http://data.pointblue.org/partners/mwadc/

Systematic conservation planning aims to design networks of protected areas that meet conservation goals across large landscapes. The optimal design of these conservation networks is most frequently based on the modeled habitat suitability or probability of occurrence of species, despite evidence that model predictions may not be highly correlated...

Little is known about viruses associated with Antarctic animals, though they are likely widespread. We recovered a novel polyomavirus from Adélie penguin (Pygoscelis adeliae) faecal matter sampled in a sub-colony at Cape Royds, Ross Island, Antarctica. The 4988 nt Adélie penguin polyomavirus (AdPyV) has a typical polyomavirus genome organisation wi...

Body size, mass and condition can affect an organism’s ability to cope with variation in resource availability or metabolic demand, particularly as juveniles become independent of their parents. It follows that changes to parental provisioning efficiency (size and frequency of meals delivered) through intraspecific competition or environmental cond...

We investigated central place foraging (CPF) in the context of optimal foraging theory in Adélie penguins Pygoscelis adeliae of the southern Ross Sea by using satellite tracking and time-depth recorders to explore foraging at two spatio-temporal scales: within the day-to-day (sub-mesoscale: single foraging trip, 10s of km2) and the entire breeding...

We investigated life history responses to extreme variation in physical environmental conditions during a long-term demographic study of Adélie penguins at 3 colonies representing 9% of the world population and the full range of breeding colony sizes. Five years into the 14-year study (1997–2010) two very large icebergs (spanning 1.5 latitude degre...

On Jan 12, 2015 this sequence version replaced gi:742287912. ##Assembly-Data-START## Assembly Method :: DNAbaser v. 4 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

Data on the extent to which the sexes may differ in their phenotypes are critical for a full understanding of the biology and management of any species. We previously quantified behavioral differences and vocal similarities between genetically-sexed Australasian Gannets (Morus serrator). Here, we quantify size monomorphism and plumage dichromatism...

Papillomaviruses are epitheliotropic viruses that have circular double stranded DNA genomes encapsidated in non-enveloped virions. They have been found to infect a variety of mammals, reptiles and birds but they have so far not been found in amphibians. Using a Next-Gen de novo assembly contig-informed recovery, we cloned and Sanger-sequenced the c...

Measurements of the size of Adélie penguin (Pygoscelis adeliae) colonies of the southern Ross Sea are among the longest biologic time series in the Antarctic. We present an assessment of recent annual variation and trends in abundance and growth rates of these colonies, adding to the published record not updated for more than two decades. High angl...

IN THE CONTEXT OF PREDICTED ALTERATION OF SEA ICE COVER AND INCREASED FREQUENCY OF EXTREME EVENTS, IT IS ESPECIALLY TIMELY TO INVESTIGATE PLASTICITY WITHIN ANTARCTIC SPECIES RESPONDING TO A KEY ENVIRONMENTAL ASPECT OF THEIR ECOLOGY: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) o...

Ade´lie penguins (Pygoscelis adeliae) are important predators of krill (Euphausia spp.) and Antarctic silverfish (Pleuragramma antarctica) during summer, are a key indicator of the status of the Southern Ocean ecosystem, and are therefore a focal species for the Committee for the Conservation of Antarctic Marine Living Resources (CCAMLR) Ecosystem...

##Assembly-Data-START## Assembly Method :: DNAbaser v. 4 Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

Adélie penguins (Pygoscelis adeliae) are important predators of krill (Euphausia spp.) and Antarctic silverfish (Pleuragramma antarctica) during summer, are a key indicator of the status of the Southern Ocean ecosystem, and are therefore a focal species for the Committee for the Conservation of Antarctic Marine Living Resources (CCAMLR) Ecosystem M...

There will be winners and losers as climate change alters the habitats of polar organisms. For an Adélie penguin (Pygoscelis adeliae) colony on Beaufort Island (Beaufort), part of a cluster of colonies in the southern Ross Sea, we report a recent population increase in response to increased nesting habitat as glaciers have receded. Emigration rates...

doi: 10.1890/ES12-00341.1

We acquired, federated and curated approximately one million new observations to the Avian Knowledge Network. We used these new and existing observations to model the distribution and abundance of 26 species of land birds in the southern portion of the North Pacific Landscape Conservation Cooperative (NPLCC) region including CA, OR and WA. The mode...

Understanding the relative effects of biotic and abiotic drivers of survival, and the interactions between them, is a key component in understanding the factors driving changes in animal populations. Body size, mass and condition may be important determinants of an organism’s ability to survive periods of low resource availiability or high metaboli...

Because nest predation strongly limits avian fitness, ornithologists identify nest predators to inform ecological research and conservation. During 2002–2008, we used both video-monitoring of natural nests and direct observations of predation to identify nest predators of open-cup nesting riparian songbirds along tributaries of Mono Lake, Californi...

Climate change-mediated impacts originating from terrestrial and marine sources interact at the coast to influence coastal habitats (Nicholls et al., 2007; Rosenzweig et al., 2007; Figure 3-1; Table 3-1). On the landward side, increased temperatures and altered precipitation patterns interact with changing land-use and land-cover practices to affec...

Background/Question/Methods The large uncertainty surrounding the effects of sea-level rise and climate change on tidal marsh habitats and the species that depend on them exacerbates the difficulty in planning effective conservation and restoration efforts. To help conservation practitioners address these effects, we modeled the distribution and a...

Foraging events and related trends in numbers of Type-B and -C killer whales (Orcinus orca) are reported for the vicinity of Ross Island, Ross Sea, Antarctica between 2002 and 2010. Updating an earlier report, the frequency of sightings and the number of individuals per sighting of Ross Sea killer whales (Type-C; RSKWs), a fishing-eating ecotype, h...

We report the analyses of a dataset spanning 39 years of near-annual fishing for Dissostichus mawsoni in McMurdo Sound, Antarctica, 1972–2011. Data on total length, condition and catch per unit effort (CPUE) were derived from the > 5500 fish caught, the large majority of which were measured, tagged and released. Con-trary to expectation, the length...

The population size of Antarctic minke whales Balaenoptera bonaerensis has been changing simultaneously with profound changes in the physics, i.e., mesopredator habitat features, of the Southern Ocean. Although the two trends may not be related, distinguishing among the factors responsible requires a better understanding of minke whale habitat pref...

a b s t r a c t Designation of an effective marine protected area (MPA) requires substantial knowledge of the spatial use of the region by key species, particularly those of high mobility. Within the Ross Sea, Antarctica, the least altered marine ecosystem on Earth, unusually large and closely interacting populations of several marine bird and mamm...

Most forecasting approaches based on statistical models and data mining methods share a set of characteristics: all are constructed from train sets and validated against test sets using methods to avoid over-fitting on the training data; standard validation methods are used (e.g., AUC values for binary response data); some form of model averaging i...

The large uncertainty associated with estimating the effects of sea-level rise and climate change on tidal marsh ecosystems exacerbates the difficulty in planning for their effective conservation. To address this uncertainty, we modeled the distribution and abundance of tidal marsh bird species in the San Francisco Estuary for the period 2010 to 21...

Long-term monitoring is essential to understand the effect of environmental change on bird populations. Ornithological field stations that have recorded detailed demographic data on bird populations over decades are well positioned to make important contributions to emerging research questions. On the basis of our experience at PRBO Conservation Sc...