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Understanding the phenology of migration is fundamental to management of migratory gamebirds, in part because of the role migratory timing plays in setting harvest regulations. Migratory timing is particularly important for determining appropriate dates for hunting seasons, which may be selected to coincide with major periods of migration, according to local management objectives. We used global positioning system (GPS)‐transmitters to track American woodcock (Scolopax minor), characterize the timing of woodcock migration, and identify sources of variation in timing relative to current hunting season structures in eastern North America. We captured 304 woodcock in 3 Canadian provinces and 12 states from 2017 to 2020, primarily within the Eastern Woodcock Management Region. Using locations collected every 1.7 days on average, we assessed whether initiation, termination, or stopover timing of woodcock migration during fall and early spring varied geographically, differed among age and sex classes, or was influenced by individual body condition. During fall, woodcock migrating from summer use areas farther north and west (e.g., Ontario, Quebec, Canada) initiated and terminated migration earlier than woodcock migrating from areas farther south and east (e.g., Rhode Island, USA). Adult woodcock made multiday stopovers that were 3 days longer on average than juveniles and females made more stopovers on average (8.0 stopovers) compared to males (6.1 stopovers). During the onset of spring migration, woodcock that wintered farther west initiated migration before birds that spent the winter farther east, and males initiated migration on average 6 days earlier than females. Under the current 45‐day harvest regulatory framework in the United States, hunting seasons in northern breeding and southern wintering areas are generally consistent with migration phenology. At more intermediate latitudes, however, periods of migration are generally longer than 45 days, resulting in many circumstances where migrating woodcock are present during periods when hunting seasons are closed. Managers in mid‐latitude states could consider opening hunting seasons later, allowing hunters to harvest more migrant woodcock. American woodcock are a popular game bird that have declined in Eastern North America. Using data from over 300 GPS‐marked woodcock, we illustrate how the timing of major migratory events such as initiation and stopover, coincide with woodcock hunting seasons. Managers can use this information in considering future changes to woodcock harvest regulations.

Effective wildlife management requires a broad understanding of how forest structure and composition influence habitat use and vital rates during all aspects of species' life-cycles, however habitat characteristics may have variable importance during different life phases. Even though the ruffed grouse Bonasa umbellusis a popular game bird that has long been a focal species for management, a greater understanding of the links between forest characteristics and components of ruffed grouse reproduction would enhance managers' ability to promote the species. We monitored 45 nests belonging to 37 females during 2015–2017 in central Maine, USA, and evaluated the influence of forest characteristics on nest-site selection, nest survival and female survival while nesting. Ruffed grouse females selected nest sites with greater horizontal visual obstruction (ß = 0.16 ± 0.06 85% CI) than found at other sites that were locally available to them, however this characteristic did not appear to improve nest survival or female survival while nesting. Cumulative nest success was 42.8% and daily nest survival was reduced when coarse woody debris (CWD) was present at nest sites (ß = –0.41 ± 0.33 85% CI), but we found no evidence that other habitat characteristics or features of nests themselves were related to nest survival. However, reduced female survival while nesting was associated with presence of CWD (ß = –1.27 ± 0.91 85% CI), greater tree basal area (ß = –0.96 ± 0.81 85% CI) and greater conifer stem density (ß = –0.45 ± 0.28 85% CI) at nest sites; females had a 74.4% chance of survival during the length of time required to successfully nest. Our results demonstrate the importance of forest characteristics on multiple components of species' nesting ecology, and we provided management suggestions to promote attractive ruffed grouse nesting habitat while potentially mitigating sources of nesting failure.

Energy development and its associated infrastructure, including power lines, may influence wildlife population dynamics through effects on survival, reproduction, and movements of individuals. These infrastructure impacts may be direct or indirect, the former occurring when development acts directly as an agent of mortality (e.g., collision) and the latter when impacts occur as a by‐product of other processes that are altered by infrastructure presence. Functional or numerical responses by predators to power‐line corridors are indirect impacts that may suppress demographic rates for certain species, and perceived predation risk may affect animal behaviors such as habitat selection. Greater sage‐grouse (Centrocercus urophasianus) are a species of conservation concern across western North America that may be affected by power lines. Previous studies, however, have not provided evidence for causal mechanisms influencing demographic rates. Our primary objective was to assess the influence of power lines on multiple sage‐grouse vital rates, greater sage‐grouse habitat selection, and ultimately greater sage‐grouse population dynamics. We used demographic and behavioral data for greater sage‐grouse collected from 2003 to 2012 in central Nevada, USA, accounting for sources of underlying environmental heterogeneity. We also concurrently monitored populations of common ravens (Corvus corax), a primary predator of sage‐grouse nests and young. We focused primarily on a single 345 kV transmission line that was constructed at the beginning of our study; however, we also determined if similar patterns were associated with other nearby, preexisting power lines. We found that numerous behaviors (e.g., nest‐site selection, brood‐site selection) and demographic rates (e.g., nest survival, recruitment, and population growth) were affected by power lines, and that these negative effects were predominantly explained by temporal variation in the relative abundance of common ravens. Specifically, in years of high common raven abundance, avoidance of the transmission line was extended farther from the line, re‐nesting propensity was reduced, and nest survival was lower near the transmission line relative to areas more distant from the transmission line. Additionally, we found that before and immediately after construction of the transmission line, habitats near the footprint of the transmission line were generally more productive (e.g., greater reproductive success and population growth) than areas farther from the transmission line. However, multiple demographic rates (i.e., pre‐fledging chick survival, annual male survival, per capitarecruitment, and population growth) for groups of individuals that used habitats near the transmission line declined to a greater extent than for individuals using habitats more distant in the years following construction of the transmission line. These decreases were correlated with an increase in common raven abundance. The geographical extent to which power lines negatively influence greater sage‐grouse demographic processes was thus contingent on local raven abundance and behavior. In this system, we found that effects of power lines, depending on the behavior or demographic rate, extended 2.5–12.5 km, which exceeds current recommendations for the placement of structures in areas around sage‐grouse leks. Nests located 12.5 km from the transmission line had 0.06 to 0.14 higher probabilities of hatching in years of average to high levels of raven abundance, relative to nests located within 1 km of the transmission line. Similarly, leks located 5 km from the transmission line had 0.02 to 0.16 higher rates of population growth (λ) in years of average to high levels of raven abundance, relative to leks located within 1 km of the transmission line. Our finding that negative impacts of the transmission line were associated with common raven abundance suggest that management actions that decouple this association between common raven abundance and power lines may reduce the negative indirect impacts of power lines on greater sage‐grouse population dynamics. However, because the removal of common ravens or the use of perch deterrents on power lines has not been demonstrated to be consistently effective in reducing common raven predation rates on greater sage‐grouse nests, we recommend preferential treatment to mitigation strategies that reduce the number of elevated structures placed within 10 km of critical greater sage‐grouse habitat. © 2018 The Wildlife Society. El desarrollo de energías, así como de su infraestructura asociada (incluyendo líneas eléctricas) puede afectar la dinámica poblacional de la vida silvestre debido a sus efectos en supervivencia, reproducción y movimiento. Estos efectos causados por la infraestructura pueden ser directos, o indirectos, los primeros, cuando la infraestructura actúa como un agente o causa de mortalidad (e.g., colisiones), y la segunda, cuando los efectos ocurren derivados de procesos que son alterados por la presencia de infraestructura. Respuestas funcionales o numéricas por depredadores a corredores de líneas eléctricas son considerados impactos indirectos que pueden reducir las tasas demográficas de ciertas especies. La percepción del riesgo de depredación puede afectar conductas tales como la selección de hábitat. El Gallo de Salvia (Centrocercus urophasianus) es una especie de preocupación para la conservación en el oeste de Norteamérica, que puede ser afectada por líneas eléctricas. Sin embargo, estudios previos no han proporcionada evidencia de los mecanismos causales que influencian las tasas demográficas. Utilizamos datos demográficos y conductuales del gallo de salvia recogidos del 2003 al 2012 en la zona centro de Nevada, USA, contemplando fuentes de heterogeneidad ambiental subyacente. Concurrentemente, monitoreamos poblaciones del cuervo común (Corvus corax), un depredador primario de nidos y jóvenes del gallo de salvia. Nos enfocamos principalmente en una línea de transmisión de 345kV que fue construida al inicio del estudio; sin embargo, también exploramos si patrones similares estaban asociados con otras líneas eléctricas cercanas. Encontramos que numerosas conductas (e.g., selección del sitio de anidación, y selección del sitio de crianza) y tasas demográficas (e.g., supervivencia del nido, reclutamiento, y crecimiento poblacional) fueron afectados por líneas eléctricas, y que estos efectos negativos fueron explicados predominantemente por variaciones temporales en la abundancia relativa del cuervo común. Específicamente, en años de alta abundancia del cuervo común, se incrementó la conducta de evitar las líneas eléctricas, la propensión a repetir un sitio de anidación se redujo, y la supervivencia en el nido se redujo en zonas cercanas a líneas eléctricas. Adicionalmente, encontramos que antes, e inmediatamente después de la construcción de la línea eléctrica, hábitats cercanos a la huella de la línea eléctricas fueron generalmente más productivos (e.g., mayor éxito reproductivo y crecimiento poblacional) en comparación con áreas alejadas de la línea de alta tensión. Sin embargo, múltiples tasas demográficas (e.g., supervivencia de juveniles, supervivencia anual de los machos, reclutamiento per cápita, y crecimiento poblacional) disminuyeron en mayor grado para grupos de individuos que utilizaron hábitats cercanos a las líneas de transmisión que para individuos que utilizaron hábitats más lejanos a las líneas de transmisión. Estas disminuciones estuvieron correlacionadas con un incremento en la abundancia del cuervo común. La extensión geográfica en que las líneas eléctricas tuvieron una influencia negativa en los procesos demográficos del gallo de salvia estuvo condicionada a la abundancia y conducta del cuervo común. En este sistema, encontramos que los efectos de las líneas eléctricas, dependiendo de la conducta o tasa demográfica, se extendieron 2.5–12.5 km, lo cual excede recomendaciones actuales para la colocación de estructuras en áreas alrededor de leks del gallo de salvia. Nidos encontrados a 12.5 km de la línea de transmisión tuvieron una probabilidad de eclosión en años de alta abundancia 0.06 a 0.14 mayor que nidos localizados a 1 km de la línea de transmisión. De manera similar, leks localizados a 5 km de la línea de transmisión, en años de alta abundancia de cuervos, tuvieron tasas de crecimiento poblacional (λ) 0.02 a 0.16 mayores que leks localizados a 1 km de la línea de transmisión. Nuestro descubrimiento de que los impactos negativos de las líneas de transmisión estaban asociados con la abundancia de cuervos, sugieren que las acciones de manejo que separen ésta asociación entre la abundancia del cuervo común y las líneas de transmisión pueden reducir los impactos negativos de las líneas eléctricas sobre la dinámica poblacional del gallo de salvia. Sin embargo, debido a que no se ha demostrado consistentemente la efectividad de la remoción de cuervos o el uso de disuasivos de percha de aves en las líneas de transmisión en la reducción de la depredación por cuervos en el gallo de salvia, recomendamos un tratamiento preferencial a las estrategias de mitigación que reduzcan el número de estructuras elevadas colocadas en un radio de 10 km de hábitat crítico del gallo de salvia. Le développement énergétique et les infrastructures associées, dont les lignes électriques, peuvent influencer les dynamiques de la vie sauvage par des effets sur la survie, la reproduction et les mouvements des individus. Ces impacts des infrastructures peuvent être directs ou indirects, ce premier ayant lieu quand le développement agit directement comme agent de mortalité (par exemple par collisions) et ce dernier quand les impacts sont le produit secondaire de l’altération d’autres processus par la présence d’infrastructures. Les réponses fonctionnelles et numériques des prédateurs aux couloirs de lignes électriques sont des impacts indirects qui pourraient écraser les taux démographiques pour certaines espèces. Aussi, perception d’un risque de prédation pourrait affecter certains comportements animaux comme la sélection d’habitat. Le tétras des armoises (Centrocercus urophasianus) est une espèce dont la conservation est préoccupante à travers l’Amérique du Nord‐Ouest et qui pourrait être affectée par les lignes électriques. Cependant, les études passées n’ont pas fourni de preuves d’un mécanisme de cause à effet influençant les taux démographiques. Notre objectif premier a été d’évaluer l’influence des lignes électriques sur de multiples indices vitaux, sur la sélection d’habitat et enfin sur la dynamique de population du tétras des armoises. Nous avons utilisé des données démographiques et comportementales pour le tétras des armoises collectées de 2003 à 2012 dans le Nevada central, aux Etats‐Unis, tenant compte des sources sous‐jacentes d’hétérogénéité environnementale. Nous suivons aussi actuellement les populations de grands corbeaux (Corvus corax), le premier prédateur des nids et des petits. Nous nous sommes concentrés principalement sur une ligne de transmission à 345kV qui a été construite au début de notre étude. Cependant, nous avons déterminé si des tendances similaires étaient associées à d’autres lignes préexistantes voisines. Nous avons trouvé que nombre de comportements (par exemple la sélection du site de nidification et la sélection du site de couvée) et de taux démographiques (par exemple le succès de nidification, le recrutement et la croissance démographique) étaient affectés par les lignes électriques et que ces effets négatifs étaient principalement expliqués par la variation temporelle de l’abondance relative du grand corbeau. Plus spécifiquement, les années de forte abondance de grands corbeaux, l’évitement des lignes électriques s’étendait au‐delà de la ligne et la propension de retour pour la nidification diminuait et la survie des nids était plus faible au voisinage de la ligne que dans les zones plus distantes de celle‐ci. De plus, nous avons trouvé qu’avant et immédiatement après la construction de la ligne électrique, les habitats au voisinage de la trace de la ligne étaient généralement plus productifs (par exemple présentant un meilleur succès reproductif et une meilleure croissance démographique) que les zones plus loin de la ligne électrique. Cependant, de multiples taux démographiques (i.e., la survie des jeunes avant leur départ du nid, la survie annuelle des mâles, le recrutement par individu, et la croissance démographique) pour des groupes d’individus qui utilisaient les habitats proches de la ligne électrique ont diminué de façon plus importante que pour les individus utilisant des habitats plus distants dans les années qui suivirent la construction de la ligne de transmission. Ces diminutions ont été corrélées à une augmentation importante de l’abondance des grands corbeaux. L’étendue géographique sur laquelle les lignes électriques influencent négativement les processus démographiques des tétras des armoises était contingente avec l’abondance locale des grands corbeaux et leur comportement. Dans ce système, nous avons trouvé que les effets des lignes électriques, dépendant du comportement et du taux démographique, s’étendait sur 2.5 à 12.5 km, ce qui surpasse les recommandations actuelles pour le placement des structures dans des zones avoisinant des aires de parades de tétras des armoises. Des nids à 12.5 km des lignes électriques avaient une probabilité d’éclosion plus haute de 0.06 à 0.14 dans des années à haute abondance moyenne de grands corbeaux, comparé à des nids situés dans une zone de 1km autour de la ligne électrique. De façon similaire, les aires de parade situées à 5km de la ligne de transmission avaient un taux de croissance démographique (λ) plus élevé de 0.02 à 0.16 pour les années à haute abondance de corbeaux, relativement aux aires de parade situés dans une zone de 1km de la ligne électrique. Notre résultat indiquant l’effet négatif des lignes électriques était associé avec l’abondance de grands corbeaux suggère que les décisions de gestion qui dissocie cette association entre abondance de grands corbeaux et lignes électriques pourraient réduire l’impact négatifs indirect des lignes électriques sur la dynamique de populations du tétras des armoises. Cependant, comme le retrait des grands corbeaux proches des lignes, et l’utilisation de dispositifs anti‐perchoir sur les lignes électriques n’ont pas montré d’efficacité constante pour la réduction du taux de prédation des nids de tétras des armoises, nous recommandons un traitement préférentiel pour des stratégies d’atténuation qui réduiraient le nombre de structures élevées placées dans les 10 km des habitats critiques du tétras des armoises. Positive associations between common raven abundance and power lines resulted in reduced use of, and reproductive success in, habitat near power lines for greater sage‐grouse in central Nevada. Management actions that effectively decouple the association between common raven abundance and power lines may reduce the negative indirect impacts of power lines on greater sage‐grouse population dynamics.

Understanding population dynamics is central to population management, particularly for game species that experience human harvest and non‐harvest mortality. Ruffed grouse (Bonasa umbellus) are a widely distributed and common game species in North America that have experienced population declines along their southern range margins, including portions of New England, primarily in response to forest succession and habitat loss. In the state of Maine, ruffed grouse are generally considered abundant, but there is a lack of state‐specific knowledge of ruffed grouse survival and harvest rates to inform harvest management. We estimated seasonal and annual survival rates, harvest rates, and documented cause‐specific mortality of 248 radio‐marked ruffed grouse at 2 study areas in central Maine from 2014 to 2016. We used Program MARK to evaluate sources of spatial, temporal, and individual variation that may affect ruffed grouse survival and harvest. Survival was lowest during October and during winter, and adult ruffed grouse had a higher survival probability than juveniles throughout the year with mean annual survival probabilities of 0.28 ± 0.01 (SE) and 0.13 ± 0.003, respectively. Harvest rates were greater in a state‐owned Wildlife Management Area and were lower within commercially managed private forest that was open to public hunting. Harvest results suggest harvest (H) was greatest at the beginning of the hunting season (Oct; Frye Mountain HOct= 0.14 ± 0.02; Stud Mill HOct= 0.07 ± 0.02), and was lower later in the season (Nov and Dec; Frye Mountain HNov‐Dec= 0.07 ± 0.02; Stud Mill HNov‐Dec= 0.03 ± 0.01). Pooled across all years and study areas, the ruffed grouse harvest rate was 0.16 (95% CI = 0.14–0.18). Our results are comparable to other range‐wide studies and suggest that current hunting regulations for ruffed grouse in Maine are consistent with sustainable population management. © 2018 The Wildlife Society. During our 3‐year study, patterns in survival of ruffed grouse in Maine appeared to be like other populations, especially those within the eastern portion of the species’ range. Our results suggest that late‐season harvest is not excessive, and current hunting regulations resulted in rates of harvest that fell within the range of values reported in other studies.

American woodcock (Scolopax minor; woodcock) are monitored, in part, by counts of displaying male woodcock collected via the American Woodcock Singing Ground Survey (SGS), which suggests long‐term, range‐wide declines in woodcock populations. Data from the SGS have been used extensively to develop conservation plans, direct management actions, and understand causes of decline. To avoid bias, the SGS should be timed to avoid spring migration, and the distribution of survey routes should coincide with woodcock breeding distribution. Our objectives for this research were to evaluate SGS timing with the phenology of male woodcock migration, relate the spatial coverage of the SGS to male woodcock breeding distributions, and explore other sources of variation in woodcock migration timing. We marked 133 male woodcock captured throughout eastern North America with global positioning system (GPS) transmitters during 2019–2022, and compared the timing of their spring migration with the spatiotemporal stratification of the SGS. Most woodcock (74%) completed migration prior to the onset of the SGS. In the northernmost SGS zone, a greater percentage of males (34%) continued migration during the survey window; however, the influence of this mismatch is offset because SGS routes were run more frequently during the second half of the window. Young woodcock completing their first spring migration took 8.6 days longer to do so, on average, compared to adults, and so were more likely to migrate during the SGS window. We found little evidence that timing of migration varied among years. Existing SGS routes cover the majority of male woodcock post‐migratory breeding distribution, with 90% of male woodcock establishing final breeding sites within the spatial coverage of the SGS. Our results confirm the SGS includes some migrating males, with the proportion relative to resident breeding males increasing in more northern survey strata. Our data suggests these errors are unlikely to bias trend estimates at large scales (e.g., within woodcock management regions), but there may be potential for bias at more local scales (e.g., state or provincial population indices). American woodcock populations are monitored by roadside counts referred to as singing ground surveys (SGS). Using GPS tracking of male woodcock, we show that survey timing and locations are fairly consistent with migration phenology in the eastern portion of their range. At least 90% of male woodcock ended migration in regions with SGS coverage, and 85−90% of males complete migration before the start of SGS survey timing.

Landscape capability (LC) models are a spatial tool with potential applications in conservation planning. We used survey data to validate LC models as predictors of occurrence and abundance at broad and fine scales for American woodcock (Scolopax minor) and ruffed grouse (Bonasa umbellus). Landscape capability models were reliable predictors of occurrence but were less indicative of relative abundance at route (11.5–14.6 km) and point scales (0.5–1 km). As predictors of occurrence, LC models had high sensitivity (0.71–0.93) and were accurate (0.71–0.88) and precise (0.88 and 0.92 for woodcock and grouse, respectively). Models did not predict point‐scale abundance independent of the ability to predict occurrence of either species. The LC models are useful predictors of patterns of occurrences in the northeastern United States, but they have limited utility as predictors of fine‐scale or route‐specific abundances. © 2017 The Wildlife Society. Landscape capability models were predictive of American woodcock and ruffed grouse occurrences but were not useful in predicting abundance. Landscape capability models may provide surrogates of present species distribution; however, they are unlikely to be informative of population densities.

Radio-transmitters are used widely in wildlife research because they allow researchers to track individual animals and monitor their activity. However, to provide unbiased information about a population, transmitters must be deployed on a representative sample of animals and must not alter the behavior of the individuals. The greater sage-grouse Centrocercus urophasianushas been studied intensively using radio-transmitters for the last several decades. A previous study demonstrated that males fitted with necklace-style radio-transmitters could be less likely to attend breeding grounds than those without transmitters. However, how transmitters affect the behavior of males that do attend leks has not been investigated. Therefore, we investigated whether radio-transmitters alter the characteristics of strut vocalizations or display frequency of male sage-grouse. We measured time and frequency characteristics of vocalizations from six collared and seven non-collared adult male sage-grouse on three leks in south-central Idaho, and for two collared and four non-collared males from two leks in northern Nevada. Only one vocalization characteristic (maximum frequency of the primary whistle) differed between collared and non-collared males across both populations. Collared males showed a lower maximum frequency of the primary whistle that typically fell outside the range of variation for non-collared males. This was the only difference found in the sample from Nevada, while in Idaho, collared males also exhibited a narrower bandwidth for the primary whistle (lower maximum frequency and higher minimum frequency), a shorter primary whistle, and a shorter secondary coo than non-collared males. Some acoustic characteristics of sage-grouse strut vocalizations are linked to mate choice by females, and therefore our results suggest that collars could reduce male mating success by altering the production of breeding vocalizations. Therefore, we recommend using alternative attachment techniques for behavioral studies of male sage-grouse.

Understanding the influence of harvest regulations on wildlife populations is crucial for successful population management and species conservation. This is true of greater sage-grouse (Centrocercus urophasianus), a species of great conservation concern in western North America that is a candidate for protection under the United States Endangered Species Act and is hunted in nine states within the United States. Recent recommendations have proposed shifting hunting seasons to later in the year, with a goal of reducing harvest of adult female and juvenile sage-grouse. Foundational principles of harvest theory, however, suggest that such changes to harvest timing could have unintentional and adverse effects on greater sage-grouse populations. I used published estimates of seasonal survival to reconstruct weekly mortality curves for adult female and juvenile greater sage-grouse in Nevada, USA. Under a hypothesis of compensatory mortality, I then calculated the maximum harvest occurring during any 1-week interval that could be compensated by non-harvest mortality that occurs after the hunting season. This value universally declines as harvest is held later in the season. Under a hypothesis of additive mortality, I calculated the realized reductions in both survival and subsequent reproductive success that would be expected for a given level of harvest. Both of these values increase if harvest is conducted later in the season, resulting in a larger additive effect than if harvest had occurred earlier. If reduced mortality of specific age or sex classes is desired, I suggest managers employ reduced bag limits, shortened season lengths, or permit systems to meet this objective. Holding hunting seasons later in the year than is presently custom (i.e., beginning sometime during Sep) should be avoided unless specific information exists to predict the change in harvest rate that would occur following changes to harvest timing. © 2015 The Wildlife Society.

The mortality process is a key component of avian population dynamics, and understanding factors that affect mortality is central to grouse conservation. Populations of greater sage-grouse Centrocercus urophasianushave declined across their range in western North America. We studied cause-specific mortality of radio-marked sage-grouse in Eureka County, Nevada, USA, during two seasons, nesting (2008-2012) and fall (2008-2010), when survival was known to be lower compared to other times of the year. We used known-fate and cumulative incidence function models to estimate weekly survival rates and cumulative risk of cause-specific mortalities, respectively. These methods allowed us to account for temporal variation in sample size and staggered entry of marked individuals into the sample to obtain robust estimates of survival and cause-specific mortality. We monitored 376 individual sage-grouse during the course of our study, and investigated 87 deaths. Predation was the major source of mortality, and accounted for 90% of all mortalities during our study. During the nesting season (1 April - 31 May), the cumulative risk of predation by raptors (0.10; 95% CI: 0.05-0.16) and mammals (0.08; 95% CI: 0.03-013) was relatively equal. In the fall (15 August - 31 October), the cumulative risk of mammal predation was greater (M(mam)= 0.12; 95% CI: 0.04-0.19) than either predation by raptors (M(rap)= 0.05; 95% CI: 0.00-0.10) or hunting harvest (M(hunt)= 0.02; 95% CI: 0.0-0.06). During both seasons, we observed relatively few additional sources of mortality (e.g. collision) and observed no evidence of disease-related mortality (e.g. West Nile Virus). In general, we found little evidence for intraseasonal temporal variation in survival, suggesting that the nesting and fall seasons represent biologically meaningful time intervals with respect to sage-grouse survival.

Populations of greater sage-grouse (Centrocercus urophasianus) are monitored using counts of males displaying on breeding leks (lek counts). When count-based indices are used to assess population growth (?), an implicit assumption is that detection is constant through time and space. If detection depends on breeding behavior, annual variation in the proportion of individuals that attend a breeding site may lead to a violation of this assumption. We used 8 years of banding data from male sage-grouse in eastern Nevada and capture–mark–recapture analyses to evaluate how temporary absence of males from lek sites during a given year may influence estimates of population trends derived from lek counts. We estimated the proportion of variance in annual lek count trends that corresponded with an independent estimate of ?, versus variance associated with temporary absence. The probability a male sage-grouse attended 1 of our study leks at least once in a given year ranged from a low of 0.56 (±0.22 SE) to a high of 0.87 (±0.11 SE). Variance in annual lek count trends was associated with both realized ? (semipartial R2?=?0.57), and sampling error associated with temporary absence (semipartial R2?=?0.40). We found discrepancies between lek count and realized ? in 3 out of 7 intervals, whereas estimates of ? for the entire study interval were extremely similar between count-based and capture–mark–recapture methods (??=?0.90?±?0.05 SE and ??=?0.91?±?0.05 SE, respectively). Temporary absence was influenced by male density during the previous year and associated with exotic grasslands surrounding leks, although some uncertainty was associated with this latter effect. Lek counts are well suited for estimating ? across multi-year intervals, whereas annual estimates of ? should be viewed cautiously if variation in annual lek attendance is not directly incorporated. © 2013 The Wildlife Society.

The development of anthropogenic structures, especially those related to energy resources, in sagebrush ecosystems is an important concern among developers, conservationists, and land managers in relation to greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) populations. Sage-grouse are dependent on sagebrush ecosystems to meet their seasonal life-phase requirements, and research indicates that anthropogenic structures can adversely affect sage-grouse populations. Land management agencies have attempted to reduce the negative effects of anthropogenic development by assigning surface use (SU) designations, such as no surface occupancy, to areas around leks (breeding grounds). However, rationale for the size of these areas is often challenged. To help inform this issue, we used a spatial analysis of sage-grouse utilization distributions (UDs) to quantify seasonal (spring, summer and fall, winter) sage-grouse space use in relation to leks. We sampled UDs from 193 sage-grouse (11,878 telemetry locations) across 4 subpopulations within the Bi-State Distinct Population Segment (DPS, bordering California and Nevada) during 2003–2009. We quantified the volume of each UD (vUD) within a range of areas that varied in size and were centered on leks, up to a distance of 30?km from leks. We also quantified the percentage of nests within those areas. We then estimated the diminishing gains of vUD as area increased and produced continuous response curves that allow for flexibility in land management decisions. We found nearly 90% of the total vUD (all seasons combined) was contained within 5?km of leks, and we identified variation in vUD for a given distance related to season and migratory status. Five kilometers also represented the 95th percentile of the distribution of nesting distances. Because diminishing gains of vUD was not substantial until distances exceeded 8?km, managers should consider the theoretical optimal distances for SU designation between 5.0?km and 7.5?km, depending on migratory status. Although these results represent space use for sage-grouse within the Bi-State DPS, our results likely have broad relevance to other areas with similar landscape characteristics and patterns of space use. © 2013 The Wildlife Society.

Lahontan cutthroat trout Oncorhynchus clarkii henshawiare listed as threatened under the U.S. Endangered Species Act. Populations inhabiting terminal lakes in the Great Basin of Utah and adjacent states face increasing salinity associated with increased anthropogenic use of water and climate change. We used tag recovery models and Markov chain–Monte Carlo methods to assess models of variation in annual survival and tag recovery rates for two genetic strains (Pilot Peak and Pyramid Lake) of Lahontan cutthroat trout stocked into Walker Lake, Nevada, from 1998 to 2008. The best-performing model of annual survival and tag recoveries allowed recovery probability in the first year after release to differ from subsequent recovery rates. The best model contained an interaction between strain and total dissolved solids (TDS) for annual survival. That is, the annual survival of both strains declined as TDS increased, but the Pilot Peak strain was more sensitive to TDS than was the Pyramid Lake strain. The annual survival of fish from the Pilot Peak strain was higher than that of the Pyramid Lake strain at all but the highest TDS levels. Although TDS levels in 2005–2008 were too high to warrant continued stocking of cutthroat trout into Walker Lake, if flows into Walker Lake are increased sufficiently to return TDS levels to those of the late 1990s, the Pilot Peak strain should be stocked. Received August 24, 2011; accepted February 6, 2012

Species associated with early successional habitats have experienced dramatic declines in the eastern United States as a result of land use changes and human disruption of natural disturbance regimes. Consequently, active management is required to create early successional habitat and promote plant and animal communities that depend on periodic forest disturbance. Ruffed grouse (Bonasa umbellus) depend on recently disturbed forest habitat, and have experienced dramatic declines over the last half-century. Although ruffed grouse are extensively studied, little effort has been made to link population dynamics with habitat management at landscape scales. We used stochastic, spatially explicit population models that combined landscape conditions derived from a Geographic Information System with demographic data, and applied the model to a declining ruffed grouse population in Rhode Island, USA. We identified vital rates that influence ruffed grouse population dynamics using baseline models constructed with current demographic rates and landscape conditions, and assessed the effect of landscape-scale forest management alternatives on population persistence by running multiple management simulations. Baseline models typically predicted population decline, and we concluded that vital rates (survival and recruitment) had a greater influence on population persistence than did dispersal capability, carrying capacity, or initial population size. Management simulations predicted greater population persistence under a scenario where high-quality habitat was provided in fewer large blocks as opposed to many small blocks, and the rate at which we allowed ruffed grouse to colonize newly created habitat had a substantial impact on management success. Populations of ruffed grouse in the eastern United States are likely to continue to decline given current disturbance regimes, and our work provides a link between ruffed grouse demography and landscape-scale habitat conditions to support management decisions. © 2011 The Wildlife Society.

Abstract:Loss of quality brood rearing habitat, resulting in reduced chick growth and poor recruitment, is one mechanism associated with decline of greater sage-grouse (Centrocercus urophasianus) populations. Low chick survival rates are typically attributed to poor-quality brood rearing habitat. Models that delineate suitability of sage-grouse nesting or brood rearing habitat at the landscape scale can provide key insights into the relationship between sage-grouse and the environment, allowing managers to identify and prioritize habitats for protection or restoration. We used Southwest Regional Gap landcover types to identify early and late greater sage-grouse brood rearing in east-central Nevada. We conducted an Ecological Niche Factor Analysis to 1) examine the effect these landcover types and other ecogeographical variables have on sage-grouse selection of brood rearing habitat, and 2) generate landscape-scale suitability maps. We also evaluated if incorporating a fitness component (brood survival) in landscape spatial analyses of habitat quality influenced our assessment of habitat suitability. Because 36% of our 6,500-km2study area was identified as early brood rearing habitat, we believe this habitat may not be limiting greater sage-grouse populations in east-central Nevada, USA, at least in wet years. We found strong selection for particular landcover types (e.g., higher elevation, moist sites with riparian shrubs or montane sagebrush) during late brood rearing. Late brood rearing habitat on which broods were successfully reared represented only 2.8% of the study area and had a restricted distribution, suggesting the potential that such habitat could limit sage-grouse populations in east-central Nevada.

Ruffed grouse Bonasa umbelluspopulations in North America have declined as forests have matured and the extent of early successional forest habitat required by the species has diminished. When wildlife species decline because of habitat loss, determining where to focus habitat management efforts is difficult because both the wildlife population and the required habitat(s) are usually limited in distribution. We adopted a relatively new ecological modeling method, partitioned Mahalanobis D2, which allowed us to predict the distribution of potential ruffed grouse habitat across a landscape of management concern where high quality habitat was uncommon. We used presence data derived from radio-telemetry locations, and GIS habitat data from publicly available sources to create competing partitioned Mahalanobis D2 models. The competing models identified important habitat variables and predicted ruffed grouse habitat distribution at 1-ha and 25-ha scales in southwestern Rhode Island, USA. The 1- and 25-ha models produced comparable overall classification accuracy (83.1% and 81.4%, respectively) but differed substantially in the area of predicted habitat (4,475.5 ha and 10,133.8 ha, respectively). We selected the more conservative 1-ha model as the ‘best’ model, and expanded it to a larger landscape extent. Once expanded, the model predicted 11,463 ha (15.5% of total land area) of potential ruffed grouse habitat for a 735-km2landscape in southwestern Rhode Island. This model identified those areas with varying proximities to the following features as likely to contain ruffed grouse habitat: early successional forests, river and stream corridors, mixed conifer forests, conifer forests, shrub wetlands and deciduous forests. Early successional forests were the most consistent component of habitat used by grouse, despite the fact that this habitat type was uncommon in our study area (< 1% of total land area). Our model can be used to identify areas of existing ruffed grouse habitat for management focus.

Adult survival is often the demographic parameter to which rate of population change is most sensitive, yet few estimates of survival exist for Greater Sage-Grouse (Certtrocercus urophasianus). We used relocations of radio-tagged sage grouse to estimate monthly survival throughout their range in Nevada. We also evaluated the relationship between hunter harvest in October and survival during October and November-December, and the relationships between late fall survival and landcover variables in sage grouse home ranges measured from Southwest Regional GAP landcover types. The best performing model of monthly survival allowed survival to vary among seven local sage grouse planning areas in Nevada. This model also allowed survival to differ between October, November-December, and other months and allowed for an additive negative effect of harvest during October. We found no evidence that landscape-level habitat variables in home ranges affected survival during fall. Annual survival varied from 0.16 ± 0.12 in the bistate area along the California-Nevada border to 0.72 ± 0.06 in the south-central area. Total harvest of sage grouse during October was negatively related to survival in October (β = -0.65 ± 0.17). Our study demonstrates the potential for substantial spatial variation in survival of sage grouse and the potential for effects of harvest. [ABSTRACT FROM AUTHOR]