Science Spotlight

Staff and volunteers of the Oiled Wildlife Care Network, managed by UC Davis, capture oiled wildlife using nets.


Staff of the Oiled Wildlife Care Network examine a bird collected from the Nov 7 2007 oil spill in San Francisco Bay.


Staff and volunteers of the Oiled Wildlife Care Network wash oil from a bird.


Staff and volunteers release rehabilitated wildlife.
 

Scientists from the California Department of Fish and Wildlife (CDFW) and University of California, Davis have published an opinion essay that advocates rehabilitation and release, rather than euthanization, of animals injured by oil spills. The essay, entitled “Life and Death: How Should We Respond to Oiled Wildlife?” can be found in the June 2018 issue of the Journal of Fish and Wildlife Management.

CDFW Environmental Scientist Laird Henkel and Dr. Michael Ziccardi, director of the Oiled Wildlife Care Network at the UC Davis School of Veterinary Medicine, argue that a coordinated effort to attempt rehabilitation of oiled wildlife is warranted on scientific, financial and ethical grounds.

Efforts to clean birds and mammals oiled by spills are not only publicly expected in California, but also mandated by laws enacted in the early 1990s. However, some critics have argued that rehabilitation is a waste of resources and that the most responsible action is to immediately euthanize impacted animals.

In their paper, Henkel and Ziccardi cite scientific studies that show oiled animals often survive just as well as non-oiled control animals, and that euthanasia should only be considered for animals unlikely to return to normal function after rehabilitation.

The scientists assert that the costs for wildlife rehabilitation are typically a very small portion of overall oil spill response costs. Costs are also typically independent of post-spill funds secured to restore impacted natural resources — the cost of cleaning wildlife does not reduce the post-spill restoration work.

From an ethical standpoint, Henkel and Ziccardi note that some people consider individual animals to have intrinsic value, and that as consumers of petroleum products, we have an obligation to reduce suffering and mitigate injuries from spills associated with the production, distribution, and use of petroleum products.

The scientists cite public safety and legal issues as additional rationale for rehabilitation. They contend that members of the public, untrained to care for animals, will attempt to help oiled animals on their own if professional organizations do not. They further assert that legislation protecting the environment is often catalyzed by public outrage over seeing oiled wildlife.

The essay can be found online at the Journal of Fish and Wildlife Management website.

For more information on oiled wildlife rehabilitation in California, visit the Oiled Wildlife Care Network, or CDFW’s Office of Spill Prevention and Response.

All photos courtesy of University of California, Davis. Cover: One of many oiled ducks being soaped and treated.

The California Department of Fish and Wildlife (CDFW) has completed its 2018 waterfowl breeding population survey -- and it’s good news for hunters and birdwatchers alike, as the total waterfowl population in the state now tops out at over a half million, for the first time in six years.

Melanie Weaver, who oversees CDFW’s Waterfowl Program, said that duck populations responded positively to the wet winter conditions of 2017. “Given the good upland and wetland habitat conditions last year from excessive precipitation, we anticipated good production,” she said. “We are pleased to see that higher recruitment reflected in this year’s breeding population survey.”

The full Breeding Population Survey Report, which can be found on the CDFW website, indicates the 2018 breeding population of mallards increased from 198,392 in 2017 to 272,859 (an increase of 38 percent). Mallards are the most abundant waterfowl species in the state, followed by gadwall (102,637) and cinnamon teal (78,498).

Other ducks that increased in number include northern shovelers, wood ducks, redhead and canvasback. Overall, the total number of ducks increased from 396,529 to 549,180 (an increase of 39 percent).

A few duck species did decline, including American wigeon, northern pintail, lesser scaup, ring-necked duck, ruddy duck and common merganser. But Weaver gave two possible explanations for these dips. First, none of these species are considered “strong nesters” in California. They migrate through the state, but don’t breed here in high numbers. And second, the survey is designed for dabbling ducks, meaning that diving ducks (such as mergansers) are harder for biologists to detect.

The survey also included Canada geese, which dropped slightly in number, from 55,224 in 2017 to 54,851 this year. (Canada geese are detected and recorded throughout the survey; however, the number reported refers to the traditional nesting population in northeastern California.)

CDFW biologists and warden pilots have conducted this survey annually using fixed-wing aircraft since 1948. The population estimates are for those areas where the vast majority of waterfowl nesting occurs in California, including wetland and agricultural areas in northeastern California, throughout the Central Valley, the Suisun Marsh and some coastal valleys.

In 2018, the survey was flown April 24-28 in the Central Valley and May 9-10 in northeastern California. A few planned survey segments were cancelled due to weather conditions (fog in the Napa-Santa Rosa area, and high winds in a few planned transects in the northeastern part of the state). However, the crew was able to cover 97 percent of the planned survey transects.

The majority of California’s wintering duck population originates from breeding areas surveyed by the U.S. Fish and Wildlife Service (USFWS) in Alaska and Canada. Those survey results should be available in early August. CDFW survey information, along with similar data from other Pacific Flyway states, is used by the USFWS and the Pacific Flyway Council when setting hunting regulations for the Pacific Flyway states, including California.

CDFW Photo

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Media Contacts:
Melanie Weaver, CDFW Wildlife Branch, (916) 445-3717
Kirsten Macintyre, CDFW Communications, (916) 322-8988