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In many southern boreal ecosystems of North America, wolves are the primary predators of white‐tailed deer, and white‐tailed deer are the primary prey of wolves. Furthermore, wolf–deer systems have and will continue to become more common as white‐tailed deer range continues expanding northward in North America. Despite this, there is little information on kill rates of wolves on deer (i.e., the number of deer killed per wolf per unit of time)—a fundamental metric of wolf predation on deer—and how kill rates vary with deer density, wolf density, and environmental conditions. We estimated kill rates of wolves on deer before, during, and after a historically mild winter in the Greater Voyageurs Ecosystem, Minnesota, USA. Kill rates of wolves on deer were low (0.009–0.018 deer/wolf/day) in fall, peaked in February (0.050 deer/wolf/day), and quickly declined to 0 deer/wolf/day by April. The kill rates of wolves on deer we observed in winter were some of the lowest kill rates of wolves on deer that have been documented. Wolves in the Greater Voyageurs Ecosystem appeared unable to catch and kill a sufficient number of deer to meet their daily energetic requirements during Winter 2023–2024, and thus most wolves likely lost weight during winter, a period when wolves are typically in peak physical condition. The rates of wolf predation we observed appeared to be well below those needed to decrease deer population density in the GVE. Thus, our work, in combination with numerous other studies, indicates winter conditions are the primary driver of deer population change in northern climates. [ABSTRACT FROM AUTHOR]

ABSTRACT Survival estimates are commonly obtained by physically capturing wildlife and marking or affixing a transmitter to a representative sample of the population. Bias induced by capture stress can occur for white-tailed deer ( Odocoileus virginianus) if capture influences the probability of mortality. To mitigate this bias, researchers often left truncate data for a threshold number of days (14-28 days for deer) after capture. Potential costs of left truncation include reduced sample size and reduced inference. Costs associated with capture and monitoring of deer are substantial, and defining a truncation period is usually arbitrary or ad hoc. Hence, researchers need to evaluate objectively the effects of left truncation. We analyzed time-to-event data from 1,001 radio-collared white-tailed deer from northern forests and eastern farmlands of Wisconsin, USA in 2011-2014 to evaluate justification for using a 2-week truncation period by comparing the probability of mortality for deer <2 weeks post-capture and deer ≥2 weeks post-capture. We found little support for a difference in mortality between the groups. Results accounting for time of year, study area, and age suggested a 0.69 probability that deer ≥2 weeks post- capture had a lower mortality rate than deer <2 weeks post-capture. Using a reference group of 6-10 -month-old deer in the eastern farmlands in 2011, cumulative capture season mortality was 0.102 (50% CI = 0.075-0.125; SE = 0.037) for deer <2 weeks post-capture and 0.114 (50% CI = 0.087-0.138; SE = 0.037) for deer ≥2 weeks post-capture. Our results suggested that when a careful review of cause-specific mortality is considered for each deer, and presumed capture-related mortalities are removed from the sample, a 2-week truncation period is unnecessary. © 2016 The Wildlife Society. [ABSTRACT FROM AUTHOR]

ABSTRACT Recent declines in black-tailed deer ( Odocoileus hemionus columbianus) populations in Washington have been attributed partly to low recruitment. However, sparse information exists regarding fawn survival and factors affecting recruitment. During 2006-2009, we captured 228 fawns on the Olympic Peninsula, Washington, USA, to determine sources of fawn mortality, estimate survival rates, identify factors influencing survival rates, assess the influence of hair loss syndrome (HLS) on winter survival, and estimate population growth. We used known fate modeling in Program MARK to estimate survival rates to age 50 weeks and to 9 weeks by developing 2 candidate a priori model sets. We recorded 129 mortalities; predation was the leading cause (74%). Mountain lions ( Puma concolor) and bobcats ( Lynx rufus) were the most common predators. The survival rate to 50 weeks was 0.33 (95% CI = 0.24-0.43); survival differed between capture years and was age dependent, with fawns being most vulnerable to mortality during the first 9 weeks then again during the winter. The survival rate to 9 weeks was 0.65 (95% CI = 0.60-0.68), and our results suggested that an interaction between age and birth mass influenced survival. A posteriori modeling indicated that greater body mass and earlier birth date also influenced survival over the first 9 weeks of life. Fawns afflicted with HLS had lower survival rates than non-afflicted fawns ( P = 0.018) during winter. Poor body condition, based on femur marrow assessment, was a factor in 89% of fawns that died over winter. We estimated the growth of the population to be stationary at λ = 1.0. Estimates of lambda increased 3% when survival was modified to assume HLS was not a factor. We conclude that fawn mortality during the first 9 weeks followed by a significant increase in winter mortality, exacerbated by HLS, combine to limit black-tailed deer population growth. Inherent nutritional limitations in summer forage may have influenced survival of many fawns, pre-disposing them to mortality during the summer and winter. Wildlife managers can use this information to improve population modeling and management of black-tailed deer populations afflicted with HLS. © 2014 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Decreases in white-tailed deer (Odocoileus virginianus) fawn recruitment have been noted at several locations across the Southeast. Understanding the reason for these decreases is important for management of deer populations. We monitored fawns from birth until 6 mo to examine age and cause specific mortality rates, at Fort Rucker, Alabama. During 2009-2010, 14 fawns were captured immediately after birth and monitored, with three surviving until 6 mo of age. Six of 7 predation events were attributed to coyotes (Canis latrans), and we determined coyote density in the study area during 2010, using DNA isolated from 44 coyote scats, to be 0.40 coyotes/km². This study, like other recent studies in the Southeast, has found low fawn recruitment seems to be driven by coyote predation. [ABSTRACT FROM AUTHOR]

The article presents a study of factors affecting the survival rate of desert mule deer in San Andres Mountains, New Mexico. The study monitored the condition, survival and causes of mortality among desert mule deer from 2003 to 2009 to assess factors behind population declines. It says that causes of mortality included predation, accidents, and malnutrition and diseases.