Trends in annual and seasonal survival of Pink-footed Geese Anser brachyrhynchus

Adult Pink-footed Geese Anser brachyrhynchus from the Svalbard breeding population were neck-banded and resighted in staging and wintering areas outside the breeding season 1990–1999. We estimated annual and seasonal survival using capture–recapture statistical models. Mean annual survival was 0.829, declining over the study period from 0.90 to 0.79. The annual cycle was partitioned into three periods: summer (1 April–30 September), including both spring and autumn migration, autumn (1 October–31 December), including most shooting, and winter (1 January–31 March). The parsimonious model selected to describe seasonal survival included a declining trend in summer survival, constant autumn and winter survival with lower survival in the severe winter of 1996, and an additive effect of sex on summer and winter survival. Monthly survival was highest during winter. Decreasing summer survival was the main contributor to the overall decline in annual survival, and was attributed mainly to increasing natural mortality on the breeding grounds. Mean annual survival based on the seasonal survival probabilities was 0.835 for females and 0.805 for males. The effect of sex was most pronounced during summer and remains to be explained.     

Annual survival of Sparrowhawks Accipiter nisus breeding in three areas of Britain

Annual survival of breeding female Sparrowhawks Accipiter nisus was estimated by a capture-recapture procedure in three different areas, Eskdale and Annandale in southern Scotland and Rockingham Forest in east-central England.
In Eskdale, where the breeding population remained fairly stable during a 19-year study, annual survival averaged 59% (s.e. = 4%). In Annandale, where the breeding population declined during a 10-year study, annual survival averaged 66% (s.e. = 4%). In Rockingham, where the breeding population increased during an 11-year study, annual survival averaged 72% (s.e. = 4%). In this area, survival declined during the study as numbers rose. The apparent density-dependence in survival was therefore confounded with a time trend.
In all three areas, annual variations in survival were negatively related to the number of rain days during October-April, but the relationship was significant only in Eskdale. This area had the longest run of data and the greatest variation in the number of winter rain days. The relationship with rain days could partly account for the differences in mean survival between areas, with lowest survival in the wettest area and highest survival in the driest.     

Climate change and annual survival in a temperate passerine: partitioning seasonal effects and predicting future patterns

Predicting climate change impacts on population size requires detailed understanding of how climate influences key demographic rates, such as survival. This knowledge is frequently unavailable, even in well‐studied taxa such as birds. In temperate regions, most research into climatic effects on annual survival in resident passerines has focussed on winter temperature. Few studies have investigated potential precipitation effects and most assume little impact of breeding season weather. We use a 19‐year capture–mark–recapture study to provide a rare empirical analysis of how variation in temperature and precipitation throughout the entire year influences adult annual survival in a temperate passerine, the long‐tailed tit Aegithalos caudatus. We use model averaging to predict longer‐term historical survival rates, and future survival until the year 2100. Our model explains 73% of the interannual variation in survival rates. In contrast to current theory, we find a strong precipitation effect and no effect of variation in winter weather on adult annual survival, which is correlated most strongly to breeding season (spring) weather. Warm springs and autumns increase annual survival, but wet springs reduce survival and alter the form of the relationship between spring temperature and annual survival. There is little evidence for density dependence across the observed variation in population size. Using our model to estimate historical survival rates indicates that recent spring warming has led to an upward trend in survival rates, which has probably contributed to the observed long‐term increase in the UK long‐tailed tit population. Future climate change is predicted to further increase survival, under a broad range of carbon emissions scenarios and probabilistic climate change outcomes, even if precipitation increases substantially. We demonstrate the importance of considering weather over the entire annual cycle, and of considering precipitation and temperature in combination, in order to develop robust predictive models of demographic responses to climate change. Synthesis Prediction of climate change impacts demands understanding of how climate influences key demographic rates. In our 19‐year mark‐recapture study of long‐tailed tits Aegithalos caudatus, weather explained 73% of the inter‐annual variation in adult survival; warm springs and autumns increased survival, wet springs reduced survival, but winter weather had little effect. Robust predictions thus require consideration of the entire annual cycle and should not focus solely on temperature. Unexpectedly, survival appeared not to be strongly density‐dependent, so we use historical climate data to infer that recent climate change has enhanced survival over the four decades in which the UK long‐tailed tit population has more than doubled. Furthermore, survival rates in this species are predicted to further increase under a wide range of future climate scenarios.     

Geographic variation and environmental correlates of apparent survival rates in adult tree swallows Tachycineta bicolor

Determining demographic rates in wild animal populations and understanding why rates vary are important challenges in population ecology and conservation. Whereas reproductive success is reported frequently for many songbird species, there are relatively few corresponding estimates of annual survival for widespread populations of the same migratory species. We incorporated mark–recapture data into Cormack–Jolly–Seber models to estimate annual apparent survival and recapture rates of adult male and female tree swallows Tachycineta bicolor in eight local breeding populations across North America for periods of 7–33 yr. We found strong site‐specific and annual variation in apparent survival rates of adult swallows, and evidence of higher survival or site fidelity among males than females. There were no strong associations between putative overwintering region and survival. Strength and patterns of winter climate‐apparent survival relationships varied across four sites monitored for >15 yr; at one site, spring pond conditions, local spring precipitation and, to a lesser extent, winter North Atlantic Oscillation Index were credible predictors of annual apparent survival. Further work is needed to evaluate how survival is related to environmental conditions throughout the annual cycle and how these factors affect population dynamics of swallows and related species of conservation concern.     

Interannual Variability in Survival Rates for Adult Female White-Tailed Deer

Adult female survival is an important component to population models and management programs for white-tailed deer (Odocoileus virginianus), but short-term survival studies (1–3 yrs) may not accurately reflect the variation in interannual survival, which could alter management decisions. We monitored annual survival and cause-specific mortality rates of adult female white-tailed deer (n = 158) for 6 years (2010–2012, 2016–2018) in southern Delaware, USA. Annual survival rate differed among years. Survival rates (±SE) and mortality causes were similar in 3 years (2011 = 0.72 ± 0.08, 2017 = 0.68 ± 0.08, 2018 = 0.74 ± 0.09) and comparable to previous research from mixed forest-agricultural landscapes. A relatively low survival rate in 2010 (0.48 ± 0.11) was influenced by hunter harvest and potentially compounded by abnormally severe winter conditions in the prior year. A peracute outbreak of hemorrhagic disease occurred during summer 2012, resulting in an annual survival rate of 0.38 ± 0.11, and to our knowledge is the first reported case of a hemorrhagic disease outbreak in a monitored wild population with known fates. In 2016, we did not observe any harvest mortality, resulting in high annual survival (0.96 ± 0.04). Our results demonstrate the degree of variability in annual survival and cause-specific mortality rates within a population. We caution against the use of short-term survival studies to inform management decisions, particularly when incorporating survival data into population models or when setting harvest objectives. © 2020 The Wildlife Society.     

Survival of radiocollared adult leopard cats<Emphasis Type="Italic">Prionailurus bengalensis</Emphasis> in Thailand

From December 1999 to December 2002, we radiocollared 25 adult (17 M, 8 F) leopard catsPrionailurus bengalensis Kerr, 1792 in Phu Khieo Wildlife Sanctuary, Thailand. We found no difference in annual survival rate between adult males (0.96 ±0.05) and females (0.87 ± 0.13), and we found no difference in mean seasonal survival rates between the dry (0.95 ± 0.04) and wet season (0.97 ± 0.04). We estimated a pooled mean annual survival of 0.92 ± 0.06 for adult leopard cats, and also estimated annual survival rates of 0.83 ± 0.24 and 0.53 ± 0.21 for leopard cats in 2 other studies. We believe our high mean annual survival estimate of adult leopard cats was related to our study site being located within a remote wildlife sanctuary with minimal anthropogenic effects.     

Climate and density influence annual survival and movement in a migratory songbird

Assessing the drivers of survival across the annual cycle is important for understanding when and how population limitation occurs in migratory animals. Density‐dependent population regulation can occur during breeding and nonbreeding periods, and large‐scale climate cycles can also affect survival throughout the annual cycle via their effects on local weather and vegetation productivity. Most studies of survival use mark–recapture techniques to estimate apparent survival, but true survival rates remain obscured due to unknown rates of permanent emigration. This is especially problematic when assessing annual survival of migratory birds, whose movement between breeding attempts, or breeding dispersal, can be substantial. We used a multistate approach to examine drivers of annual survival and one component of breeding dispersal (habitat‐specific movements) in a population of American redstarts (Setophaga ruticilla) over 11 years in two adjacent habitat types. Annual survival displayed a curvilinear relation to the Southern Oscillation Index, with lower survival during La Niña and El Niño conditions. Although redstart density had no impact on survival, habitat‐specific density influenced local movements between habitat types, with redstarts being less likely to disperse from their previous year's breeding habitat as density within that habitat increased. This finding was strongest in males and may be explained by conspecific attraction influencing settlement decisions. Survival was lowest in young males, but movement was highest in this group, indicating that apparent survival rates were likely biased low due to permanent emigration. Our findings demonstrate the utility of examining breeding dispersal in mark–recapture studies and complement recent work using spatially explicit models of dispersal probability to obtain greater accuracy in survival estimates.     

Effects of variable spring harvest regimes on annual survival and recovery rates of male wild turkeys in Southeast Louisiana

Spring harvest is a primary mortality factor for male eastern wild turkeys (Meleagris gallopavo silvestris), but the relationship between spring harvest regimes and annual survival is not well understood. We banded 462 male wild turkeys from 1989 to 2007 in southeastern Louisiana to estimate annual survival and band recovery rates relative to spring harvest. We evaluated these parameters under a liberal harvest season (3-bird limit; 1989–1997) and a reduced conservative harvest season (2-bird limit; 2000–2007). Estimated recovery rates during the liberal season were 0.75 (SE = 0.05) for adults and 0.63 (SE = 0.04) for juveniles, and recovery rates during the conservative season were 0.61 (SE = 0.04) and 0.48 (SE = 0.05) for adults and juveniles, respectively. Annual survival averaged 0.16 (SE = 0.05) and 0.43 (SE = 0.05) for adults and juveniles, respectively, during the liberal season. Conversely, during the conservative season, annual survival averaged 0.31 (SE = 0.05) and 0.56 (SE = 0.05) for adults and juveniles, respectively. Our findings suggest that bag limit reductions combined with a reduction in season length contributed to a 2-fold increase in annual survival for male wild turkeys. We contend that male wild turkeys were likely over harvested on our study area during the liberal harvest season, which contributed to exceptionally low annual survival rates. Managers should attempt to assess survival rates of male wild turkeys in harvested populations to properly manage spring harvest and develop appropriate harvest limits. © 2012 The Wildlife Society.     

Evaluation of reproductive costs for Weddell seals in Erebus Bay, Antarctica

1. Organisms balance current reproduction against future survival and reproduction, which results in life-history trade-offs. These trade-offs are also known as reproductive costs and may represent significant factors shaping life-history strategy for many species. 2. Using multistate mark-resight models and 26 years of mark-resight data (1979-2004), we estimated the costs of reproduction to survival and reproductive probabilities for Weddell seals in Erebus Bay, Antarctica and evaluated whether this species either conformed to the 'prudent parent' reproductive strategy predicted by life-history theory for long-lived mammals or alternatively, incurred costs to survival in order to reproduce in a variable environment (flexible-strategy hypothesis). 3. Results strongly supported the presence of reproductive costs to survival (mean annual survival probability was 0.91 for breeders vs. 0.94 for nonbreeders), a notable difference for a long-lived mammal, demonstrating that investment in reproduction does result in a cost to survival for Weddell seals, contrary to the prudent parent hypothesis. 4. Reproductive costs to subsequent reproductive probabilities were also present for first-time breeders (mean probability of breeding the next year was 31.3% lower for first-time breeders than for experienced breeders), thus supporting our prediction of the influence of breeding experience. 5. We detected substantial annual variation in survival and breeding probabilities. Breeding probabilities were negatively influenced by summer sea-ice extent, whereas weak evidence suggested that survival probabilities were affected more by winter sea-ice extent, and the direction of this effect was negative. However, a model with annual variation unrelated to any of our climate or sea-ice covariates performed best, indicating that further study will be needed to determine the appropriate mechanism or combination of mechanisms underlying this annual variation.     

Effects of sexual differences of age at maturity and survival on population sex ratio

Summary Five demographical factors influencing the sex ratio of a population are classically considered. The influence of two of them is dependent on the longevity of individuals in the population. The effect of differential age at maturity between males and females is higher for animals with low annual survival, whereas the effect of differential annual survival between males and females is higher for animals with high annual survival. Such a conclusion applied to turtles, which are long life-span animals, allows us to retain differential survival between sexes as a major factor influencing the population sex ratio.     

Bigger is better: age class-specific survival rates in long-lived turtles increase with size

Vital rates for small, non-breeding individuals are important components of population dynamics for many species, but often individuals of these sizes are difficult to locate, capture, and track. As such, biologists frequently lack reliable estimates of juvenile survival because sample sizes and recapture rates for this life stage are low. Long-lived animals often take many years to reach sexual maturity and spend much of this time in the smaller size classes, making them sensitive to changes in survival rates. We estimated the survival rates of all size classes for the northern map turtle (Graptemys geographica) using a mark-recapture dataset with >3,500 captures from 2019–2021 and 210 nests from 2018–2021. As turtle size increased, annual survival probability increased regardless of sex. Estimated annual survival probability for turtles >18 cm long (i.e., adult females >15 years) was about 0.95, over 4 times higher than turtles that were 3 cm long (i.e., hatchlings <1 year; 0.22 annual survival probability). Although we did not observe a difference in survival probability between sexes of any size class, adult females are nearly twice the size of adult males, leading to an increased annual survival probability for females of 0.95, compared to 0.80 for males. Changes in adult survival had the greatest influence on population estimates over time, with temporary decreases, such as those due to poaching or an environmental disaster, potentially leading to unrecoverable decreases in the overall population size. Our study provides detailed survival rates for all size classes in a long-lived turtle, which are necessary to assess population stability and can be used to determine the most effective conservation or management practices.     

Climatic conditions during outward migration affect apparent survival of an arctic top predator,the peregrine falcon Falco peregrinus

In long‐lived species, population growth rate is highly sensitive to changes in adult survival. Despite the growing concerns regarding recent climate changes, few studies have investigated the effect of climatic conditions on survival in long‐lived wildlife that are either resident or breed in the Arctic. In this study, we evaluated the effect of climate across the annual life cycle (breeding, outward migration, wintering, and inward migration) on apparent annual survival of arctic‐breeding peregrine falcons. From 1982 to 2008, peregrine falcons breeding near Rankin Inlet, Nunavut, Canada were monitored, in part, to assess apparent annual survival (the product of true survival and site fidelity) using re‐observations of marked individuals. Our study indicated that apparent annual survival of adult peregrine falcons was correlated with indices of climatic conditions during outward migration (i.e., flight from the Arctic breeding grounds). These climatic indices (fall NAO of the current year and fall NAO with a lag of one year) explained 35% of the temporal variation in apparent annual survival of peregrine falcons. Our results suggest that this top‐predator is vulnerable to weather‐related environmental conditions encountered during fall migration.     

Adult survival and reproductive rate are linked to habitat preference in territorial,year‐round resident Song Sparrows Melospiza melodia

Individual animal fitness can be strongly influenced by the ability to recognize habitat features which may be beneficial. Many studies focus on the effects of habitat on annual reproductive rate, even though adult survival is typically a greater influence on fitness and population growth in vertebrate species with intermediate to long lifespans. Understanding the effects of preferred habitat on individuals over the annual cycle is therefore necessary to predict its influences on individual fitness. This is particularly true in species that are resident and territorial year‐round in the temperate zone, which may face potential trade‐offs between habitat that maximizes reproduction and that which maximizes non‐breeding season (‘over‐winter’) survival. We used a 37‐year study of Song Sparrows Melospiza melodia residing territorially year‐round on a small island to examine what habitat features influenced adult over‐winter survival, how site‐specific variation in adult survival vs. annual reproductive rate influenced long‐term habitat preference, and if preferred sites on average conferred higher individual fitness. Habitat features such as area of shrub cover and exposure to intertidal coastline predicted adult over‐winter survival independent of individual age or sex, population size, or winter weather. Long‐term habitat preference (measured as occupation rate) was better predicted by site‐specific annual reproductive rate than by expected over‐winter survival, but preferred sites maximized fitness on average over the entire annual cycle,. Although adult over‐winter survival had a greater influence on population growth (λ) than did reproductive rate, the influence of reproductive rate on λ increased in preferred sites because site‐specific variation in reproductive rate was higher than variation in expected over‐winter survival. Because preferred habitats tended to have higher mean site‐specific reproductive and adult survival rates, territorial birds in this population do not appear to experience seasonal trade‐offs in preferred habitat but are predicted to incur substantial fitness costs of settling in less‐preferred sites.     

Population dynamics of the Grey Partridge Perdix perdix 1793–1993: monitoring, modelling and management

The longest available bag record of Grey Partridges Perdix perdix in Great Britain (1793–1993) reveals a collapse of stocks after 1952 despite considerable annual variation. The annual fluctuations were attributable largely to annual variations in chick survival rate. The Game Conservancy Trust's National Game Census revealed that chick survival rates averaged 49% before the introduction of herbicides and 32% once their use became widespread. On a study area in Sussex, where spring density declined from around 21 pairs per km² in 1968 to under four pairs per km² in 1993, annual chick survival rates averaged 28% with no demonstrable trend. The annual over-winter "survival" rates in the area improved during 1968–1993, whereas brood production rates declined. Simulation modelling showed that a reduction in chick survival rate from 49% to 32% had little effect on spring stocks as long as nest predation was controlled but that stocks collapsed when nest predation control was relaxed. The effect of such a change in chick survival rate on population status was investigated by reference to 36 other studies in the literature. Amongst 20 studied populations which were stable, adjusting mean chick survival rates downwards produced demographic parameters characteristic of declining populations in all but two cases. Conversely, adjusting chick survival rates upwards for 16 declining populations made all but two stable. Diagnosing and remedying the causes of population change require a testable understanding of density-dependent factors and compensatory processes, best approached by a combination of monitoring, modelling and management.     

Survival of Adult Martens in Northern Wisconsin

Abstract: Low adult marten (Martes americana) survival may be one factor limiting their population growth >30 yr after their reintroduction in Wisconsin, USA. We estimated annual adult marten survival at 0.81 in northern Wisconsin, with lower survival during winter (0.87) than summer-fall (1.00). Fisher (Martes pennanti) and raptor kills were infrequent, and each reduced marten adult annual survival <10%. Annual adult survival was similar to or higher than survival in other areas, suggesting that it was not unusually low and therefore did not limit recovery of marten populations in northern Wisconsin. We captured few juvenile martens, suggesting low reproduction or reduced juvenile survival.     

Age‐ and sex‐specific survival of California sea lions (Zalophus californianus) at San Miguel Island,California

We conducted a mark‐recapture study of California sea lions (Zalophus californianus) using pups branded on San Miguel Island, California, from 1987 to 2014, and annual resightings from 1990 to 2015. We used the Burnham model (Burnham 1993), an extension of the Cormack‐Jolly‐Seber mark‐recapture model, which includes recoveries of dead animals, to analyze age, sex, and annual patterns in survival. Generally, females had higher survival than males. For female pups, the average annual survival was 0.600 and for male pups it was 0.574. Yearling survival was 0.758 and 0.757 for females and males, respectively. Peak annual survival was at age 5 and was 0.952 for females and 0.931 for males. Pups with larger mass at branding had higher survival as pups and yearlings, but the effect was relative within each cohort because of large between‐cohort variability in survival. Annual variability in sea surface temperature (SST) affected survival. For each 1°C increase in SST, the odds of survival decreased by nearly 50% for pups and yearlings; negative SST anomalies yielded higher survival. Annual variation in male survival was partly explained by leptospirosis outbreaks. Our study provides a unique view of one demographic parameter that contributed to the successful recovery of the California sea lion population.     

Correlates of survival in Swainson's hawks breeding in northern California

We used a 30-year study of breeding Swainson's hawks (Buteo swainsoni) in northern California to examine correlates of adult apparent survival using multistate models in Program MARK. Specifically, we examined age-related patterns in adult apparent survival and how adult survival was correlated with average annual nest productivity, annual reproductive output, western juniper (Juniperus occidentalis) density around nest sites, distance to agriculture, and amount of agriculture within a territory. Annual estimates of adult survival varied from 0.85 to 0.9 (SE = 0.02). There were no indications of senescence or other patterns of age-related changes in adult apparent survival. Adult survival was inversely correlated with average reproductive output, with individuals producing >2 offspring having decreased survival, reflecting a possible trade-off between reproduction and survival. Conversely, reproduction in any year was positively correlated with survival, providing evidence of individual quality influencing adult survival. The distance an individual had to travel to agriculture, where most individuals forage, was negatively related to survival. Primary productivity within the average Swainson's hawk territory was positively correlated with adult survival. Our results indicate that individuals may have higher survival and fitness in areas with high proportions of irrigated agriculture that provides high prey densities, particularly alfalfa. © 2011 The Wildlife Society.     

Seasonal survival estimation for a long-distance migratory bird and the influence of winter precipitation

Conservation of migratory animals requires information about seasonal survival rates. Identifying factors that limit populations, and the portions of the annual cycle in which they occur, are critical for recognizing and reducing potential threats. However, such data are lacking for virtually all migratory taxa. We investigated patterns and environmental correlates of annual, oversummer, overwinter, and migratory survival for adult male Kirtland’s warblers (Setophaga kirtlandii), an endangered, long-distance migratory songbird. We used Cormack–Jolly–Seber models to analyze two mark–recapture datasets: 2006–2011 on Michigan breeding grounds, and 2003–2010 on Bahamian wintering grounds. The mean annual survival probability was 0.58 ± 0.12 SE. Monthly survival probabilities during the summer and winter stationary periods were relatively high (0.963 ± 0.005 SE and 0.977 ± 0.002 SE, respectively). Monthly survival probability during migratory periods was substantially lower (0.879 ± 0.05 SE), accounting for ~44% of all annual mortality. March rainfall in the Bahamas was the best-supported predictor of annual survival probability and was positively correlated with apparent annual survival in the subsequent year, suggesting that the effects of winter precipitation carried over to influence survival probability of individuals in later seasons. Projection modeling revealed that a decrease in Bahamas March rainfall >12.4% from its current mean could result in negative population growth in this species. Collectively, our results suggest that increased drought during the non-breeding season, which is predicted to occur under multiple climate change scenarios, could have important consequences on the annual survival and population growth rate of Kirtland’s warbler and other Neotropical–Nearctic migratory bird species.     

The survival rate of Lanyu Scops Owls Otus elegans botelensis

Few species of owls have been well studied in the wild and estimates of survival rates are available only for a few species in the temperate region. This paper reports the adult annual and monthly survival estimates of the Lanyu Scops Owl Otus elegans botelensis , a subtropical Asian species, based on a 13-year study of a colour-marked population. The estimated seasonal survival pattern was relatively stable, with an indication of lower survival during May-June, the time of egg-laying and chick-rearing. Female survival in this species was consistently higher than male survival by an estimated 7%, which may have resulted from differential costs in reproduction. Annual survival rates during 1986-96 showed no significant differences between years. Based on a model with constant survival and annual variation in recapture rate, average annual survival for all birds was estimated as 75%, which is higher than expected given the small body weight of the Lanyu Scops Owl. This survival and the stable monthly survival pattern are discussed in light of the mild subtropical conditions of Lanyu Island.     

Survival and Recovery Rate of Canada Geese Staging in Interior Alaska

Abstract: Lesser Canada geese (Branta canadensis parvipes) are indistinguishable from other subspecies of small Canada geese on the wintering grounds using current survey methods. Consequently, managers are unable to adequately measure their abundance. Without direct estimates of abundance, researchers often use estimates of vital rates that influence abundance (e.g., annual survival) to monitor potential impact of harvest on the population. Based on capture and re-sighting data records of 567 geese marked from 1994 through 1998, we calculated annual survival and recovery rates for different age and sex classes of white-cheeked geese staging in interior Alaska. We compared those survival and recovery rates with those of other neck-collared white-cheeked geese. The best approximating model allowed survival to vary by age class while holding Seber's recovery probability (r̂) constant over sex, age class, and time. We estimated annual survival to be 0.49 (SE = 0.05) for hatch-year geese and 0.68 (SE = 0.03) for after-hatch-year geese based on the weighted average of all models with a change in Akaike's Information Criterion adjusted for small sample size and lack of fit < 4. Estimates of annual survival of white-cheeked geese in this study are among the lowest and recovery estimates are among the highest for migratory populations of neck-collared geese. Low survival estimates of Canada geese in our study suggest that harvest rates may be higher than in many other populations. Surveys to estimate abundance or other population parameters such as reproductive success and recruitment are necessary to determine whether this population is self-sustaining. Furthermore, we recommend monitoring abundance and harvest of small white-cheeked geese east and west of the Cascade Mountain Range separately to better determine harvest pressure on white-cheeked geese wintering east of the Cascades.