Snow Geese Research Articles

Evidence for seasonal compensation of hunting mortalities in a long‐lived migratory bird

Abstract Understanding whether hunting mortality is additive to or compensated by other mortality sources is at the heart of managing harvested populations. Long‐lived species are expected to exhibit hunting mortality additive to other sources of mortality, making them ideal candidates for population management through sport harvest. Previous studies on these processes have focussed on density‐dependent natural mortality compensating for hunting mortality, but when harvest occurs in distinct periods of the year, heterogeneity in hunting vulnerability between individuals could also lead to compensatory mortality between these periods. We explore this new idea using the case of the greater snow goose (Anser caerulescens atlantica), a harvested species whose population became overabundant in the late 20th century. To control this population, wildlife agencies liberalised hunting regulations with unprecedented actions such as special hunting seasons implemented in spring 1999 in Canada and in winter 2009 in the USA. To determine the relative impact of each measure on survival, we estimated survival of adult geese on a seasonal basis using 30 years of capture‐mark‐reencounter data in a joint live‐and‐dead‐encounter multievent model. We also used this quasi‐experimental set‐up to evaluate possible compensation in hunting mortality between seasons. We found that both special hunting seasons decreased goose survival in the seasons and periods in which they were implemented. However, survival increased during the spring hunting season after the establishment of the special winter hunting season in the USA in 2009. There was a negative relationship between annual spring and winter mortalities, suggesting that the increase in hunting mortality in winter was compensated by a reduction in spring mortality after 2009. Synthesis and applications: To our knowledge, we report the first documented instance of hunting mortality in one season being compensated by a reduction in hunting mortality in a subsequent season. We suggest that heterogeneity in hunting vulnerability among individuals, possibly linked to the presence of juveniles, may explain this phenomenon. A better knowledge of seasonal patterns and relationships between mortality components is needed to improve our understanding of population dynamics and management of harvested populations.

Genetic diversity and phylogeographic dynamics of avihepadnavirus: a comprehensive full-length genomic view.

Avihepadnavirus is a genus of the Hepadnaviridae family. It primarily infects birds, including species of duck, geese, cranes, storks, and herons etc. To understand the genetic relatedness and evolutionary diversity among avihepadnavirus strains, a comprehensive analysis of the available 136 full-length viral genomes (n = 136) was conducted. The genomes were classified into two major genotypes, i.e., GI and GII. GI viruses were further classified into 8 sub-genotypes including DHBV-I (duck hepatitis B virus-I), DHBV-II (Snow goose Hepatitis B, SGHBV), DHBV-III, RGHBV (rossgoose hepatitis B virus), CHBV (crane hepatitis B virus), THBV (Tinamou hepatitis B virus), STHBV (stork hepatitis B virus), and HHBV (Heron hepatitis B virus). DHBV-I contains two sub-clades DHBV-Ia and DHBV-Ib. Parrot hepatitis B virus (PHBV) stains fall into GII which appeared as a separate phylogenetic branch/clade. All the subtypes of viruses in GI and GII seem to be genetically connected with viruses of DHBV-I by multiple mutational steps in phylogeographic analysis. Furthermore, 16 potential recombination events among different sub-genotypes in GI and one in GII were identified, but none of which is inter-genotypic between GI and GII. Overall, the results provide a whole picture of the genetic relatedness of avihepadnavirus strains, which may assist in the surveillance of virus spreading.

Scale-dependent effects of herbivory on moss communities in Arctic wetlands: A 25-year experiment.

Arctic ecosystems are undergoing rapid changes, including increasing disturbance by herbivore populations, which can affect plant species coexistence and community assemblages. Although the significance of mosses in Arctic wetlands is well recognized, the long-term influence of medium-sized herbivores on the composition of moss communities has received limited attention. We used data from a long-term (25 years) Greater Snow Goose (Anser caerulescens atlanticus) exclusion experiment in Arctic tundra wetlands to assess changes in the composition of moss communities at multiple spatial scales (cell, 4 cm2; quadrat, 100 cm2; exclosure, 16 m2). We investigated how snow goose grazing and grubbing can alter the composition of the moss community by measuring changes in alpha and beta diversity, as well as in the strength of plant interspecific interactions between moss species. Our results indicate that goose foraging significantly increased species diversity (richness, evenness, and inverse Simpson index) of moss communities at the cell and quadrat scales but not the exclosure scale. Goose foraging reduced the dissimilarity (beta diversity) of moss communities at all three scales, mainly due to decreased species turnover. Furthermore, goose foraging increased positive interaction between moss species pairs. These findings emphasize the critical role of geese in promoting moss species coexistence and increasing homogeneity in Arctic wetlands. This study illustrates how top-down regulation by herbivores can alter plant communities in Arctic wetlands and highlights the importance of considering herbivores when examining the response of Arctic plant biodiversity to future climate change.

Geese migrating over the Pacific Ocean select altitudes coinciding with offshore wind turbine blades

Abstract Renewable energy facilities are a key part of mitigating climate change, but can pose threats to wild birds and bats, most often through collisions with infrastructure. Understanding collision risk and the factors affecting it can help minimize impacts on wild populations. For wind turbines, flight altitude is a major factor influencing collision risk, and altitude‐selection analyses can evaluate when and why animals fly at certain altitudes under certain conditions. We used GPS tags to track Pacific Flyway geese (Pacific greater white‐fronted goose, tule greater white‐fronted goose and lesser snow goose) on transoceanic migrations between Alaska and the Pacific Coast of the contiguous United States, an area where offshore windfarm development is beginning. We evaluated how geographic and environmental covariates affected (1) whether birds were at rest on the water versus in flight (binomial model) and (2) altitude selection when in flight (similar to a step‐selection framework). We then used a Monte Carlo simulation to predict the probability of flying at each altitude under various conditions, considering both the fly/rest decision and altitude selection. In both spring and fall, geese showed strong selection for altitudes within the expected rotor‐swept zone (20–200 m asl), with 56% of locations expected to be within the rotor‐swept zone under mean daylight conditions and 28% at night. This indicates a high possibility that migrating geese may be at risk of collision when passing through windfarms. Although there was some variation across subspecies, geese were most likely to be within the rotor‐swept zone with little wind or light tailwinds, low clouds, little to no precipitation and moderate to cool air temperatures. Geese were unlikely to be in the rotor‐swept zone at night, when most individuals were at rest on the water. Synthesis and applications. These results could be used to inform windfarm management, including decisions to shut down turbines when collision risk is high. The altitude‐selection framework we demonstrate could facilitate further study of other bird species to develop a holistic view of how windfarms in this area could affect the migratory bird community as a whole.

Can arctic migrants adjust their phenology based on temperature encountered during the spring migration? The case of the greater snow goose

The reproductive phenology of many long-distance migrants breeding at high latitudes remains unresponsive or responds only slightly to climate warming. In order to adjust migration speed and arrival time on the breeding grounds, environmental cues encountered during the migration must be related to conditions prevailing at the breeding site. However, heterogeneity in rate of climate warming across latitudes may hamper the ability of birds to adjust their migration speed adequately. We examined to what extent temperatures encountered at stopovers were a good predictor of temperatures at subsequent stopovers and at the breeding site in greater snow geese (Anser caerulescens atlanticus), an Arctic species that showed little change in its breeding phenology over the past 3 decades. We also examined temperature trends at various stopovers used by geese and at the breeding site over a 40-year period. We found that warming was stronger at the Arctic stopovers and the breeding site than at southern staging areas. The mean temperature and rate of temperature change encountered at the southern stopover, where this species accumulates most of its body reserves, was weakly correlated to temperatures prevailing at more northern stopovers and the breeding site located 3,000 km further north. Correlations in temperatures between stopovers and the breeding site increased with decreasing distance between sites and as geese moved further north. Lastly, laying date was strongly related to temperature during the arrival and pre-laying period on the breeding grounds but not to temperatures encountered at stopovers during migration. Temperatures encountered along the migratory route are thus a poor predictor of temperatures prevailing at the breeding site in any given year except when geese are getting close to their breeding grounds. This may be a major constraint preventing geese from adjusting their migratory schedule to conditions on their breeding grounds and may explain why their reproductive phenology did not change despite a warming trend at the breeding site.

Worth the dip? Polar bear predation on swimming flightless greater snow geese and estimation of energetic efficiency

As sea-ice cover is shrinking, polar bears ( Ursus maritimus, Phipps, 1774) face decreased access to seals, their primary prey, resulting in a greater dependence on terrestrial food sources. Whether polar bears can benefit from these terrestrial food sources, however, depends on their ability to find and capture prey items without expending more energy than is acquired. Here, we report one of the northernmost observations of polar bear predation on adult birds. The bear used a dive-hunting technique, which consisted of submerging itself, approaching underwater, and catching flightless greater snow geese ( Anser caerulescens caerulescens (Linnaeus, 1758)) from beneath the surface of a tundra pond. After evaluating energy expenditures during swimming and energy intakes from consuming geese, we estimated that this rarely documented dive-hunting technique could be energetically profitable for a certain range of pursuit durations. This observation highlights the behavioral plasticity that polar bears can deploy to punctually exploit land-based food sources.

Movement behavior, habitat selection, and functional responses to habitat availability among four species of wintering waterfowl in California

IntroductionHabitat selection analyses provide a window into the perceived value of habitats by animals and how those perceptions compare with other animals, change across time, or change in relation to availability (termed functional responses). Habitat selection analysis and functional responses can be used to develop strategies to avoid habitat limitations, guide habitat management, and set attainable conservation goals. GPS relocations of marked animals are the principal data used in habitat selection analysis. The accuracy and frequency with which tracking devices collect data are increasing and may result in non-stationary point processes that result from latent behaviors previously unidentifiable in sparse data.MethodsWe investigated non-stationary step length distributions and integrated a two-mixture model of animal movement with step selection analysis to identify patterns of activity among four species of co-occurring waterfowl that winter in the Central Valley of California, United States. We evaluated relative strength of selection and compared functional responses across a range of habitat types for two goose and two dabbling duck species.ResultsGoose species (greater white-fronted goose [Anser albifrons] and lesser snow goose [Anser caerulescens caerulescens]) used habitats similarly and displayed similar functional responses with habitat availability. Northern pintail (Anas acuta) displayed functional responses for habitats that provided primary food resources and sanctuary from hunting that were more similar to geese than to mallard (Anas platyrhynchos), which expressed a more generalist pattern of habitat selection.DiscussionOur results define conditions where food resource competition between geese and ducks could operate, which indicate that some species may be more impacted than others. Specifically, early season food limitation may manifest more strongly in snow geese due to longer movements and stronger functional response with rice availability. Late season limitations may manifest in northern pintail, which remain reliant on rice later but may not be reflected in habitat selection patterns due to a consistent functional response with rice availability. We show that multiple movement processes present in high-resolution data can be used to obtain a variety of information about animal behavior and that subsequent step selection analyses may demonstrate unique functional responses relative to alternate habitat selection methods that warrant additional investigation.

Long-term study of the tundra food web at a hotspot of Arctic biodiversity, the Bylot Island Field Station

We present the history of research activities at the Bylot Island Field Station of the Centre d’études nordiques, a hotspot of biodiversity in the Canadian Arctic. Intensive wildlife studies started at the station in the late 1980s, initially focussing on greater snow goose ecology and its impacts on the tundra vegetation. Since then, studies have expanded to encompass the whole vertebrate food web and have become one of the most comprehensive ecological monitoring programs in the Canadian Arctic. The main vertebrate species monitored include snow geese, lemmings, shorebirds, avian predators, buntings, and Arctic foxes. Over time, we recorded 66 bird and 10 mammal species, including 51 confirmed breeders. Contributions of the program to the field of ecology are numerous, but our demonstration of the dominant role played by predator–prey interactions in the Arctic food web is especially significant for the understanding of direct and indirect trophic interactions. Our studies provided essential information for management decisions taken to control the overabundant greater snow goose population and supported international efforts to assess the state of Arctic biodiversity. Future directions will reflect the need to deepen our understanding of trophic interactions and the effects of climate change using innovative advanced technologies.

Additional data confirms the impact of the COVID19 lockdown on the behavior and fattening of migratory snow geese

The COVID19 lockdown provided a unique opportunity to study the impact of human activities and conservation measures on wildlife. However, most lockdown studies were opportunistic and based on limited data, because this ‘natural experiment’ was unexpected and short-lasting. Replication of scientific results is the cornerstone of the scientific method and ensures that conclusions from such short-term studies are robust. Here, we test predictions arising from a previous study where we showed the impact of the lockdown-induced reduction in hunting disturbance on the body condition and behavior of greater snow geese (Anser caerulescens a.), a species whose management is crucial for the conservation of northern ecosystems. The analysis of two additional years of data confirmed our predictions. The return to a high hunting pressure in springs 2021–2022 (post-lockdown) reduced overall goose body condition compared to the lockdown year. Goose fattening in post-lockdown springs was very similar to pre-lockdown years, differing from 2020 when a high body condition was reached earlier in spring than in any other year. Radio-tracked birds spent more time in profitable but risky agricultural lands in 2021 compared to 2020, as was the case in the pre-lockdown year. Our study provides robust evidence confirming the impacts of spring hunting on greater snow goose physiology. It demonstrates the long-lasting efficiency of the spring conservation hunt established two decades ago to limit the size of the population with the aim of preserving Arctic ecosystems from overgrazing and associated negative impacts on other arctic-nesting birds.

Heavy metal concentrations in Canada geese, snow geese, mallards, and American coots from the northern Rocky Mountains in Montana

AbstractThe presence of metals in migratory bird tissues is well established and mining as an anthropogenic source of exposure to metals is well reported in the scientific literature. Determining the difference between what are hypothesized as normal metal levels and those associated with acute mining toxicity is challenging as spatial and temporal overlap of migratory birds with anthropogenic point sources can be highly variable at individual, population, and species levels. We examined the concentrations of 5 geologically prominent metals and metalloids in the region (arsenic, cadmium, copper, manganese, and zinc) in tissues (kidney, n = 64; liver, n = 65; and muscle, n = 65) from 4 species common to the northern Rocky Mountains in western Montana (Canada goose, Branta canadensis, n = 12; snow goose, Anser caerulescens, n = 15; mallard, Anas platyrhynchos, n = 32; and American coot, Fulica americana, n = 6), to identify metal concentrations for comparison to acute mining‐associated mortalities. Metal levels were highly variable across tissue types for all species. For example, the highest concentrations of copper, manganese, and zinc were measured in the liver (18,300, 3,960, and 38,200, respectively; ug/kg), while cadmium levels were highest in the kidney (973 ug/kg). Among species and tissue types, metal levels were also highly variable. For example, copper levels in mallards were highest in the kidney (6,700 ug/kg) and lowest in muscle (2,780 ug/kg). In contrast, copper levels in American coots were highest in muscle (14,400 ug/kg) and lowest in the kidney (5,060 ug/kg). While the wide variation in metal concentrations among species and tissue types measured in our study can make for difficult comparisons, the results are similar to control cases from other peer‐reviewed publications, and several times lower than dose‐response experiments and incidents in which mining‐associated mortality was known. Our results provide metal concentrations in migratory bird species that utilize the northern Rocky Mountains through Montana, which are essential data for assessing exposure, risk, and mortality associated with anthropogenic activities in the region.

Avian species survey with citizen-science data in Janghang Wetland, Goyang, Republic of Korea.

Monitoring of avian populations in Janghang Wetland, Goyang, Republic of Korea (ROK) is based on citizen science (also called community-based monitoring). This monitoring data can be used to track avian density, population status and waterbird census at local, national and regional levels. The Ministry of Environment (MoE) ROK has surveyed since 1999, including Odusan Unification Tower to Ilsan Bride, which connects the cities of Gimpo and Goyang along the Han River estuary. However, it has not covered Janghang Wetland, which is located in the Han River estuary at the transboundary between the two Koreas. The Janghang Wetland is a protected wetland in the Demilitarized Zone (DMZ) between the two Koreas. In 2019, Janghang Wetland was designated as a Flyway Network Site by Goyang City and the East Asian-Australasian Flyway Partnership. This Network site is a voluntary collaboration and includes many internationally significant wetlands for waterbirds that still lack formal national protection. In addition, it was designated as a Ramsar site in 2021. The wetland currently supports wintering population of White-naped Crane (Grusvipio), species listed as vulnerable and Tundra Bean Goose (Ansercygnoides), spring-autumn migration population of Swan Goose (Ansercygnoid), species listed as vulnerable and a breeding population of Black-faced Spoonbill (Plataleaminor), species listed as endangered in summer. We provide data that the Janghang Wetland is a significant area for migration and breeding for waterbirds; and that Han River estuary is also internationally important for waterbirds during the migratory bird season. We observed 14 orders, 42 families and 132 species. The surveys also observed the critically-endangered Black-faced Spoonbill (Plataleaminor), Swan Goose (Ansercygnoides), White-naped Crane (Grusvipio), Whooper Swan (Cygnuscygnus) and Peregrine Falcon (Falcoperegrinus). We also observed the Black-faced Spoonbill, Great Egret, Little Egret, Great Cormorant, Eastern Spot-billed Duck, Pheasant and Brown-eared Bulbul at the sensor camera point and White-naped Crane, Hooded Crane, Bean Goose, White-fronted Goose, Snow Goose, Swan Goose, Great Cormorant and Eastern Spot-billed Duck at the closed-circuit television camera point from the camera-trap surveys. Based on the species recorded, the survey area is of clear importance for biodiversity conservation.

Availability of Supplemental Corn for Sandhill Cranes, Light Geese, and Dabbling Ducks Wintering in New Mexico

Abstract The Middle Rio Grande Valley of central New Mexico overwinters the majority of the Rocky Mountain Population of greater sandhill cranes Antigone canadensis tabida and numerous Midcontinent Population lesser sandhill cranes A. c. canadensis, light geese (i.e., snow Anser caerulescens and Ross's geese Anser rossii), and dabbling ducks (i.e, Anas spp.). Stemming from changes in agricultural practices and loss of habitat, these species have become largely dependent on public lands where corn supplements natural foraging resources, providing a key dietary component while also discouraging crop depredation on private lands. To evaluate if supplemental corn provides a sufficient resource base, we estimated energy available in corn resources and seasonal energy requirements of the sandhill cranes, which consisted of the Rocky Mountain Population and Midcontinent Population. Additionally, we considered energetic requirements for two other wintering guilds, light geese and dabbling ducks. Depletion rates of postmowed corn increased throughout winter from 3,673 ± 843 kg/ha/d (mean ± SE) in December to 7,014 ± 1,884 kg/ha/d in February. The estimated seasonal energetic requirement of the Rocky Mountain Population and Midcontinent Population was 1.14 × 109 kcal (95% CI = 1.07 × 109 to 1.21 × 109 kcal). The combined seasonal energetic demand of the Rocky Mountain Population, Midcontinent Population, light geese, and dabbling ducks was 4.23 × 109 kcal (95% CI = 3.81 × 109 to 4.53 × 109 kcal) or 911,813 kg of corn (95% CI = 820,821–1,006,894 kg). From 2014 to 2017, corn production on public lands in the Middle Rio Grande Valley was 1,052,006 ± 58,965 kg grown on an average of 76 ha, sufficient for winter energetic requirements of all guilds. Interagency collaboration, effective planning during the growing season, and strategic schedules for mowing supplemental corn crops that integrate population abundances and their respective energy demands should further promote success of the supplemental corn program in the Middle Rio Grande Valley.

Should I breed or should I go? Manipulating individual state during migration influences breeding decisions in a long‐lived bird species

Abstract Documentation of carry‐over effects (COEs), defined as effects resulting from events that occurred in a previous time period, has largely been observational and understanding of specific mechanisms underlying COEs is still lacking. To investigate this, we simulated an environmental perturbation during the spring migration of a long‐lived bird species and looked at the subsequent effects on various breeding parameters. We captured female greater snow geese Anser caerulescens atlanticus on their spring staging sites and maintained individuals in captivity for up to 4 days before releasing them. We re‐observed females 3000 km North, on their Arctic breeding grounds, to estimate their breeding propensity (i.e. probability of initiating a reproductive event for a given year), and measured their arrival date, laying date, clutch size and nesting success. Only proxies of breeding propensity were affected by our manipulation, which decreased as the time spent in captivity increased. However, females were able to overcome the effects of captivity in two out of the 3 years of experimentation with normal or good environmental conditions at the breeding site. When facing the additional challenge of poor environmental conditions, many individuals manipulated during migration apparently curtailed their reproductive effort by skipping breeding. This experiment is the first to show that breeding propensity is an important parameter affected by COEs resulting from stressful events prior to reproduction in long‐lived species. Read the free Plain Language Summary for this article on the Journal blog.

Studies on parasitic prevalence in pet birds from Punjab, Pakistan.

During this one year study, blood and fecal samples of doves (Zenaida asiatica), ducks (Anas platyrhynchos), pigeons (Columba livia), partridges (Alectoris chukar), turkeys (Meleagris gallopavo) and goose (Chen caerulescens) were collected to assess the parasitic prevalence in these birds. The birds were kept at Avian Conservation and Research Center, Department of Wildlife and Ecology, University of Veterinary and Animal Sciences, Lahore. All these avian species were kept in separate cages and their entire body was inspected on regularly basis to record external parasites. For internal parasites, 100 blood and 100 fecal samples for each species were analyzed. During present study, two species of ectoparasites i.e. fowl ticks (Args persicus) and mite (Dermanyssus gallinae) while 17 species of endoparasites; three from blood and 14 from fecal samples were identified. Prevalence of blood parasites was Plasmodium juxtanucleare 29.3%, Aegyptinella pullorum 15% and Leucoctoyzoon simond 13%. Parasitic species recorded from fecal samples included 6 species of nematodes viz. Syngamus trachea with parasitic prevalence of 50%, Capillaria anatis 40%, Capillaria annulata 37.5%, Heterakis gallinarum 28.3%, Ascardia galli 24% and Allodpa suctoria 2%. Similarly, two species of trematodes viz. Prosthogonimus ovatus having parasitic prevalence of 12.1% and Prosthogonimus macrorchis 9.1% were also recorded from fecal samples of the birds. Single cestode species Raillietina echinobothrida having parasitic prevalence of 27% and 3 protozoan species i.e. Eimeria maxima having prevalence 20.1%, Histomonas meleagridis 8% and Giardia lamblia 5.3% were recorded. In our recommendation, proper medication and sanitation of the bird's houses and cages is recommended to avoid parasites.

Identifying Bird Species in River Yuman Oral Traditions

Identifying Bird Species in River Yuman Oral Traditions Jonathan A. Geary (bio) 1. Introduction Nearly 400 bird species occur along the lower Colorado River (Rosenberg et al. 1991), and Yuman communities that have historically lived along the lower Colorado surely knew and named many of them. However, judging from modern sources, this knowledge has been fading over time. For example, the ~6,700-entry Mojave dictionary (Munro et al. 1992; also spelled "Mohave") lists 105 unique bird names, and past speakers likely knew specific species referents for many of these, yet 53 are glossed as a "type of" something while many others are given generic definitions that preclude identifying an exact species referent (e.g., 'big bird', 'chickenhawk', 'eagle'). Studying such knowledge today is complicated by at least three factors: (1) changes to traditional ecological knowledge that have accompanied man-made changes to the lower Colorado River ecosystem, which has caused many species to decline while allowing other formerly-rare or new species to expand their use of the lower Colorado (Rosenberg et al. 1991: 14–28); (2) historical migrations away from the lower Colorado River and toward the Gila and Salt Rivers in central Arizona by the Piipaash (also spelled "Pee Posh", a.k.a. "Maricopa"; see Rea 1983, 2007 for changes to the Gila River ecosystem); and (3) the general decline in the intergenerational transmission of linguistic and cultural knowledge that Yuman communities have experienced. However, we can turn to the information that past speakers of these languages shared with early linguists and anthropologists about these birds, especially through their oral traditions, to identify exact referents for many such names, and thus reconstruct a small part of the rich ecological knowledge that they possessed. [End Page 538] In this paper, I analyze three bird names that recur in the oral traditions of the River Yuman languages: Mojave, Piipaash, and Quechan (a.k.a. "Yuma"). These bird names include (1) Mojave yaːlák, Piipaash yalák, and Quechan yaːlák; (2) Mojave humaθéː and Piipaash xomasé; and (3) Mojave hanavčíːp, Piipaash xnvčíːp, and Quechan xanavcíːp, which have been glossed as a range of different bird species across Yuman sources. I show that Yuman speakers maintained rich knowledge of these birds (e.g., about their appearance, hunting behaviors, and nests) which they incorporated into their traditions, and based on this information I identify these species as (1) Snow Goose (Anser caerulescens), (2) Ferruginous Hawk (Buteo regalis), and (3) Verdin (Auriparus flaviceps). To my knowledge, these names have not been identified as referring to these species in past sources. Further, the range of glosses that these names have received in more modern sources suggests that much of the ornithological knowledge contained in past sources has faded over time. This research stems from a larger effort to identify the bird species named in Piipaash and other Yuman languages (e.g., Geary 2022).1 Underpinning this work is the assumption that Yuman oral narratives contain valuable descriptive information about birds and bird characters that reflect the appearance and behavior of their natural-world counterparts, which I have found to be well supported in my work. Yuman oral traditions often explain how birds and other animal characters received their names as well as salient physical and behavioral characteristics during mythic times that their natural-world counterparts have exhibited since then until now. For example, versions of the creation story that were recorded in Mojave (Bourke 1889; Kroeber 1972: 9) and Havasupai (Smithson and Euler 1994: 38) describe how rising floodwaters stained the Red-shafted Northern Flicker's (Colaptes auratus) tail feathers, whose undersides are red with black tips, accounting for their current appearance. A Quechan version of the creation story (Halpern 1984: 322) similarly explains how floodwaters stained the tail of Mourning Dove (Zenaida macroura), which became white when the waters receded, explaining their current appearance. Mojave (Bourke 1889: 187) and Piipaash versions of the same story (Spier 1933: 391) further describe how Northern Flicker drank the blood of a murdered pair of twin brothers, staining its feathers and so accounting for the red malar stripes that are visible on male Red-shafted Northern Flickers. Finally, a Mojave...

Morphological differences and migration patterns of greater and lesser snow geese in New York State

AbstractLesser (Chen caerulescens caerulescens, LSGO) and greater snow goose (Chen caerulescens atlantica, GSGO) populations have increased substantially in the past 50 years. The light goose conservation order established in 1998 (Canada) and 1999 (U.S.) aimed to increase snow goose harvest and stabilize populations because breeding ground abundance was thought to negatively impact arctic ecosystems. In the Atlantic flyway, where LSGO and GSGO are both available for harvest, techniques to differentiate sub‐species in the field using morphology may be helpful for harvest management because mid‐continent LSGO are ~16 times more abundant than GSGO (n < 1,000,000). We investigated percentages and spatial distribution of LSGO and GSGO in the spring harvest in NY as this information could be useful for snow goose population and harvest management decisions. We developed a discriminant function analysis (DFA) using heads from snow geese harvested during spring 2016 to 2018 and were able to differentiate between LSGO and GSGO with 95.5% accuracy. Based on the DFA results, we estimated that spring harvest in New York state was 80% GSGO and 20% LSGO. Using band recoveries from autumn and spring harvests, we also identified that GSGO harvest occurred farther west during spring than autumn and in the 2010s than prior two decades. Our results indicate that GSGO comprise most snow goose harvest in New York state and provide evidence for a shift in spring migration patterns of GSGO since the 1990s.

Reduction in biomass of freshwater arctic vegetation by foraging and nesting hyperabundant herbivores shows recovery

AbstractArctic‐nesting geese are specialist herbivores of grasses and sedges (collectively, graminoids). Under moderate grazing pressure, these migratory herbivores can create and maintain arctic grazing lawns with high nutritional content and low aboveground biomass. Nutrient and energy subsidies from southern agricultural landscapes during winter have improved survival among populations of Ross's (Anser rossii) and lesser snow geese (Anser caerulescens caerulescens), leading to marked population growth. Resulting goose hyperabundance has raised conservation concern for resilience of arctic ecosystems to withstand cumulative and intense pressures of herbivory and nest construction. We used both design‐based (experimental herbivore exclosures) and model‐based methods to investigate changes to plant community structure in direct response to foraging and nesting by these species within the Queen Maud Gulf (Ahiak) Migratory Bird Sanctuary, Nunavut, Canada. Annual nest construction and foraging by up to ~1.3 million geese at a large colony at Karrak Lake markedly reduced aboveground biomass of forage (graminoids) and non‐forage (foliose and fruticose lichens) vegetation, with spatial variation in reduction associated with intensity of use by geese. Within vast brood‐rearing regions, foraging reduced above‐ and belowground plant biomass of lowland plant communities by 61% and 29%, respectively, between 1994 (when herbivore exclosures were established) and 2017. In addition to landscape diversity associated with abiotic properties created by geomorphic processes, long‐term herbivory by geese further increased spatial heterogeneity in vegetation at the landscape scale. Although foraging geese nearly completely depleted aboveground plant biomass in some parts of their brood‐rearing areas, belowground biomass was largely conserved, and thus, plant communities had strong potential for aboveground regeneration. We propose that the effects of high‐density nesting and foraging by Ross's and lesser snow geese in the central Canadian Arctic, while extensive, are ephemeral and prone to reversion following cessation of grazing and nesting pressure, such as that afforded by shifts in herbivore distribution or local population decline.

Evidence for synergistic cumulative impacts of marking and hunting in a wildlife species

Abstract Nonadditive effects from multiple interacting stressors can have unpredictable outcomes on wildlife. Stressors that initially have negligible impacts may become significant if they act in synergy with novel stressors. Wildlife markers can be a source of physiological stress for animals and are ubiquitous in ecological studies. Their potential impacts on vital rates may vary over time, particularly when changing environments impose new stressors. In this study, we evaluated the temporal changes in the combined impact of two stressors, one constant (collar marking) and another one variable over time (hunting intensity), in greater snow geese (Anser caerulescens atlantica). Over a 30‐year period (1990–2019), hunting regulations were liberalized twice, in 1999 and 2009, with the instauration of special spring and winter hunting seasons respectively. We evaluated the effect of collars on goose survival through this period of changing hunting regulations. We compared annual survival of >20,000 adult females marked with and without neck collars using multi‐event capture–recapture models, and partitioned hunting from nonhunting mortality. Survival of geese marked with or without collars was similar in 1990–1998, before hunting regulations were liberalized (average survival [95% CI]: 0.87 [0.86, 0.89]). However, absolute survival of collared geese was 0.05 [0.03, 0.07] lower than that of noncollared geese between 1999 and 2009, and 0.12 [0.09, 0.15] lower after hunting regulations were liberalized further in 2009. Hunting and nonhunting mortality probabilities were both higher in collared birds compared to those without collars. The interaction between the effects of collars and hunting was synergistic because collars affected survival only after the hunting pressure increased significantly. These cumulated stresses probably reduced goose body condition sufficiently to increase their vulnerability to multiple sources of mortality.

Multi‐image flock size estimation with CountEm: A case study with half a million Common Eiders and Greater Snow Geese

AbstractMany of the methods used for estimating population size from ecological surveys have limitations on precision, cost, and/or applicability. The CountEm method was proposed recently for estimating the number of individuals in large groups from single images. It is simple and efficient, and can be applied to any species. Here we present a case study by applying CountEm to a real ecological survey with 278 images of Greater Snow Geese (Anser caerulescens atlanticus) and Common Eiders (Somateria mollissima) flocks taken from fixed‐wing aircraft in Eastern Canada. First, we evaluated the precision and counting time of CountEm on single images. Second, we developed and tested a new multi‐image version of the CountEm software. We show that flock sizes of N > 35,000 can be estimated on single images in ∼5 min, from counting a sample of ∼200 birds, yielding relative SEs in the 5%−10% range. Processing times increased to 10–20 min when simultaneously processing large numbers of images that contained over half a million birds with only modest increases in relative SE (range: 10%−15%). Our results suggest that CountEm may be used to save time and resources if incorporated into monitoring programs that utilize imagery in the abundance estimates.

Subpopulation contributions to a breeding metapopulation of migratory arctic herbivores: survival, fecundity and asymmetric dispersal

Estimates of demographic parameters for lesser snow geeseAnser caerulescens caerulescenshave become critical to understand ecosystem change in northern Canada. Exponential increase in abundance has produced hyperdensities of these herbivores that can affect Arctic ecosystem stability through intense foraging. Increased and sustained marking of individually‐identifiable lesser snow geese over their breeding distribution now permits joint estimation of local vital rates and movement probabilities among widely scattered subpopulations. We used multi‐state models, including an unobservable state, with live captures from 5 subpopulations and dead recoveries to estimate annual probabilities of 1) survival, 2) capture, 3) reported mortality and 4) movement to other subpopulations, as well as derived estimates for probabilities of site fidelity and harvest. Our dataset included 144 719 captures of 139 177 lesser snow geese marked with metal legbands, from 2006 to 2015, of which 5542 were recaptured near breeding sites and 9709 were recovered dead in North America. The best model supported variation in survival by subpopulation and age, with additive effects of subpopulation, age and sex on movement probability. Male breeding dispersal was greater than by females, and juvenile geese were more likely to move than adults. Strong northeastward geographic asymmetry in the probability of breeding movement was consistent with an eastward shift in wintering distribution observed in hunter recoveries. Mean annual survival ranged from 0.79 to 0.94 for adults, and 0.16 to 0.47 for juvenile geese, with a strong negative relationship between regional adult and juvenile survival. Harvest probabilities were all ≤ 0.03 for adult and ≤ 0.06 for juvenile geese, suggesting little influence from direct anthropogenic exploitation. Metrics for subpopulation persistence and contributions of each to the metapopulation suggested declines in all but one subpopulation, and a declining Midcontinent population overall. Our study highlights the importance of all subpopulation demographic parameters as modulators of persistence at both local and range‐wide population dynamics.