David W Wolfson

University of Minnesota | UMN · Fisheries, Wildlife, and Conservation Biology

Motion‐activated cameras (“camera traps”) are increasingly used in ecological and management studies for remotely observing wildlife and are amongst the most powerful tools for wildlife research. However, studies involving camera traps result in millions of images that need to be analysed, typically by visually observing each image, in order to ext...

Motion-activated wildlife cameras (or “camera traps”) are frequently used to remotely and noninvasively observe animals. The vast number of images collected from camera trap projects has prompted some biologists to employ machine learning algorithms to automatically recognize species in these images, or at least filter-out images that do not contai...

Technological advances in the field of animal tracking have greatly expanded the potential to remotely monitor animals, opening the door to exploring how animals shift their behaviour over time or respond to external stimuli. A wide variety of animal‐borne sensors can provide information on an animal's location, movement characteristics, external e...

Incorporating memory (i.e., some notion of familiarity or experience with the landscape) into models of animal movement is a rising challenge in the field of movement ecology. The recent proliferation of new methods offers new opportunities to understand how memory influences movement. However, there are no clear guidelines for practitioners wishin...

Integrated step‐selection analysis (ISSA) is frequently used to study habitat selection using animal movement data. Methods for incorporating random effects in ISSA have been developed, making it possible to quantify variability among animals in their space‐use patterns. Although it is possible to model variability in both habitat selection and mov...

The Interior Population (IP) of Cygnus buccinator (Trumpeter Swan), formerly extirpated by market hunting, was re-established in eastern North America by releasing individuals from both migratory and non-migratory populations. Their current annual movement patterns are largely unknown. We deployed 113 GPS-GSM transmitters on IP C. buccinator in 6 U...

Incorporating memory (i.e., some notion of familiarity or experience with the landscape) into models of animal movement is a rising challenge in the field of movement ecology. The recent proliferation of new methods offers new opportunities to understand how memory influences movement. However, there are no clear guidelines for practitioners wishin...

Conservation of North American migratory birds requires information about their movements and regulating factors throughout the annual cycle. Over the past 10 or more years, improvements in tracking technology and quantitative approaches to assessing resulting data have yielded advances in understanding many aspects of North American bird migration...

Background The Interior Population (IP) of trumpeter swans ( Cygnus buccinator ), formerly extirpated by market hunting, was re-established in eastern North America by releasing individuals from both migratory and non-migratory populations. Their current annual movement patterns are largely unknown. Our goal was to describe their seasonal movements...

Daily activity patterns of animals can be dynamic across seasons in response to changing environmental conditions. Daily activity, though, has rarely been evaluated in relation to multiple factors (e.g., seasons, demographics, and data collection methods), which could be important for understanding what drives activity patterns. Here, we evaluated...

Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studi...

Integrated step-selection analyses (ISSAs) are frequently used to study animal movement and habitat selection. Methods for incorporating random effects in ISSAs have been developed, making it possible to quantify variability among animals in their space-use patterns. Although it is possible to model variability in both habitat selection and movemen...

Invasion of nonindigenous species is considered one of the most urgent problems affecting native ecosystems and agricultural systems. Mechanistic models that account for short-term population dynamics can improve prediction because they incorporate differing demographic processes that link the environmental conditions of a spatial location explicit...

Age-structured population models require reliable estimates of cohort-specific survival rates, yet vital rates of younger age classes are often difficult to estimate because of the logistical challenges of monitoring young animals. As part of a study of sandhill cranes Antigone canadensis in the zone of contact between breeding distributions of the...

Invasion of nonindigenous species is considered one of the most urgent problems affecting native ecosystems and agricultural systems. Mechanistic models that account for short-term population dynamics can improve prediction because they incorporate differing demographic processes that link the environmental conditions of a spatial location explicit...

Technological advances in the field of animal tracking have greatly expanded the potential to remotely monitor animals, opening the door to exploring how animals shift their behavior over time or respond to external stimuli. A wide variety of animal-borne sensors can provide information on an animal's location, movement characteristics, external en...

Invasion of nonindigenous species is considered one of the most urgent problems affecting native ecosystems and agricultural systems. Mechanistic models that account for short-term population dynamics can improve prediction because they incorporate differing demographic processes that link the environmental conditions of a spatial location explicit...

The Interior Population (IP) of trumpeter swans (Cygnus buccinator) was established through extensive re-introductions beginning in the late 1960s throughout the Upper Midwest. Across much of their current breeding distribution, IP trumpeter swans have transitioned from a rare to a common component of the regional waterfowl community. However, unli...

This study analyzes the impact the National Feral Swine Damage Management Program (NFSDMP) has had on feral swine damage and population management.

1. Motion-activated wildlife cameras (or "camera traps") are frequently used to remotely and non-invasively observe animals. The vast number of images collected from camera trap projects have prompted some biologists to employ machine learning algorithms to automatically recognize species in these images, or at least filter-out images that do not c...

Motion-activated wildlife cameras (or “camera traps”) are frequently used to remotely and non-invasively observe animals. The vast number of images collected from camera trap projects have prompted some biologists to employ machine learning algorithms to automatically recognize species in these images, or at least filter-out images that do not cont...

The Interior Population (IP) of trumpeter swans (Cygnus buccinator) was established through extensive re-introductions beginning in the late 1960s throughout the Upper Midwest. To date, the primary conservation objective for IP trumpeter swans has been to re-establish breeding populations across their historical distribution. Since those early rest...

Sandhill Cranes Antigone canadensis exhibit delayed sexual maturity and breeding, and therefore juvenile Cranes searching for suitable territories to occupy have different ecological constraints on movements than adults, which must defend a territory and raise young. We used fine‐scale GPS telemetry data to characterize and compare movements of adu...

Success of large‐scale control programs for established invasive species is challenging to evaluate because of spatial variability in expansion rates, management techniques, and the strength of management intensity. For a well‐established invasive species in the spreading phase of invasion, a useful metric of impact is the magnitude by which contro...

Machine Learning for Wildlife Image Classification (MLWIC) is an R package that allows users to automatically classify animal species in camera trap images. The package comes with a build in model that was trained to recognize 27 North American species using over 3.7 million images. It works rapidly (> 2,000 images/minute on a laptop computer) and...

1. Motion-activated cameras (“camera traps”) are increasingly used in ecological and management studies for remotely observing wildlife and have been regarded as among the most powerful tools for wildlife research. However, studies involving camera traps result in millions of images that need to be analyzed, typically by visually observing each ima...

Sandhill cranes (Antigone canadensis) are long-lived birds with relatively low recruitment rates, making accurate knowledge of abundance and distribution critical for well-informed harvest management. Minnesota, USA, is one of few states containing portions of 2 distinct breeding populations of greater sandhill cranes (A. c. tabida)—the Mid-contine...

Background/Question/Methods The reduced genetic diversity of small, bottlenecked populations renders them vulnerable to the effects of inbreeding depression. In many cases inbreeding depression may be the most immediate factor limiting growth in threatened populations, but difficulty in demonstrating its occurrence in the wild can hinder manageme...

Sandhill cranes are an important part of Minnesota’s natural heritage, and although they have expanded their breeding range in Minnesota, they remain a species of management concern. Minnesota supports two populations of sandhill cranes– the Mid-continent Population that breeds and migrates through northwestern Minnesota, and the Eastern Population...