The Wildlife Professional

From The Journal of Wildlife Management (JWM) and Wildlife Monographs

Extra Food Aids Mule Deer Mule deer (Odocoileus hemionus) populations across the West declined in the 1990s, prompting research into possible reasons why, specifically looking at predation and habitat quality. In one such study, detailed in Wildlife Monographs (v. 172/1), Colo- rado Division of Wildlife biologist Chad Bishop and colleagues probed the habitat side of the equation. They supplemented the diets of part of a mule deer population in southwestern Colorado and observed the response over four years. The largest effect could be seen on survival of fawns. Those given extra food

WILDLIFE

MONOGRAPHS

No. 172, July 2009

Effect of Enhanced Nutrition on

Mule Deer Population Rate of

Change

Chad J. Bishop, Gary C. White, David J. Freddy,

Bruce E. Watkins, and Thomas R. Stephenson

Supplement to The Journal of Wildlife Management

Credit: t Ws

had survival rates between 16 and 31 percent higher than those left to fend for themselves. Adult female survival rates also jumped with enhanced nutrition. The population growth rate was significantly higher among mule deer given extra food, and those deer were less likely to be predated by coyotes and mountain lions. The study’s results indicate that food is the limiting factor in mule deer population growth, and not predation by mountain lions, which may target weak or older mule deer. The authors advise those managing for mule deer population growth, therefore, to focus on improving habitat productivity.

MANAGEMENT THE JOURNAL OF

WILDLIFE

(ISSN 0022-541X)

Vol. 73, Issue 5, July 2009

TrumpeterSwanPopulationGrowth Black-FootedFerretAbundance

Credit: t Ws

Yellowstone’s Swan Song A population of trumpeter swans (Cygnus buccinator) in Yellowstone National Park, which helped restore the once-threatened species across the country in the early-20th century, is now in severe decline. Using 40 years’ worth of data on the abundance of trumpeter swans in the park, Kelly Proffitt of Montana State University led an effort to uncover the cause of the downward trend, reporting the results in JWM (v. 73/5). From a high of 59 swans in 1968, the population had fallen to 10 in 2007. The scientists analyzed several models of annual population growth, one of which indicated that population declines accelerated after a supplemental feeding program outside the park’s boundaries ceased in the early 1990s, as well as after severe winters, wet springs, and warm summers—all of which diminish swan nesting success. The authors suggest that the Yellowstone swans may eventually leave the park for more favorable habitat, and urge the National Park Service to collaborate on trumpeter swan management with agencies and groups who manage habitat in surrounding areas.

MANAGEMENT

THE JOURNAL OF

WILDLIFE

(ISSN 0022-541X)

Vol. 73, Issue 6, August 2009

Leg Band Loss in Wild Turkeys

Survival of Female Harlequin Ducks

Credit: t Ws

Snacks for Grouse Chicks Managers of greater sage grouse (Centrocercus uro-phasianus) have largely blamed the population’s decline since the 1950s on poor habitat quality, but few had taken a close look at the factors influencing daily chick survival. To fill this gap, Michael Gregg of the U.S. Fish and Wildlife Service and John Crawford of Oregon State University tracked 506 radio-marked grouse chicks from 94 broods in northwestern Nevada and southeastern Oregon for over a month, keeping detailed records of prey species availability and habitat cover. Reporting in JWM (v.73/6), they found that availability of Lepidoptera and slender phlox, high-quality foods for grouse chicks, were the only habitat variables that correlated with increased survival. The specificity of the findings suggest that

habitat managers could boost short-term chick and brood survival, and ultimately sage-grouse populations, by increasing host plants available to butterfly and moth species in the months of May and June, early in the brood-rearing cycle for sage grouse.

Could Scavengers Contract CWD? A team of researchers from the University of Wisconsin led by Christopher Jennelle has published a report in JWM (v. 73/5) that may shed light on the potential of chronic wasting disease (CWD) to spread to species that scavenge on infected carcasses. CWD affects deer by attacking neural tissues, causing extreme weight loss and eventual death. Found in more than a dozen states and Canadian provinces, the illness to date has been seen only in mule deer, white-tailed deer, elk, and moose. Some fear, however, that it could infect other species, perhaps even humans. To learn which species might be vulnerable to the spread, Jennelle’s team placed 40 disease-free white-tailed deer carcasses and 10 gut-piles in parts of Wisconsin where CWD is endemic, then, over two years, monitored the animals that scavenged upon the remains. Remote cameras captured images of 14 mammal and 14 bird species feeding on the remains, including crows, raccoons, and domestic dogs, cats, and even cows. Despite a lack of firm evidence indicating that CWD could affect humans and other species, the authors note that testing deer-carcass scavengers for the disease could be a useful strategy to monitor its spread.