Science Spotlight

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  • July 5, 2018

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
 

Categories: Wildlife Research
  • July 3, 2018

Woman holding dead nutria
CDFW dog trainer Lynette Shimek uses a dead nutria (caught in the Central Valley) to train Star and Trigger to search and locate the body as well as residual odor from the carcass

Woman in waders and orange shirt stands in water with dog
Successful nutria detection dogs have to spend a lot of time in the water searching for nutria scent and scat. One of the unknowns when dog training began in May was whether Trigger, a German shepherd, would take to water work. He quickly allayed any concerns.

Black dog with red collar sitting with person standing behind holding leash
K9 Star

German Shepherd dog sitting with tongue out wearing orange collar
K9 Trigger

Meet the newest members of CDFW’s “Team Nutria;” a 1-year-old female black Labrador retriever named Star and a 2-year-old male German shepherd named Trigger.

The two scent-detection dogs, their handlers and CDFW’s top canine trainer officially joined CDFW’s nutria eradication effort in late May. The two dogs have been undergoing training to detect nutria scent, scat and residual odor. Recently certified as being proficient at their work, the dogs will soon be deployed to the marshes, wetlands and riparian habit in California’s Central Valley where CDFW teams already have captured some 200 invasive nutria since eradication efforts began this spring.

Star and Trigger are learning quickly and drawing praise.

“Both of these dogs are exceptional to begin with and they are exceeding expectations with how quickly they are adapting to the environment they will be working in,” said Lynette Shimek, CDFW’s canine trainer.

Nutria are semi-aquatic rodents native to South America that have turned up in the Central Valley’s marshes and wetlands and on the edge of the Sacramento-San Joaquin Delta. Their destructive feeding and burrowing threaten the critical wetland habitat needed by native species and jeopardizes the state’s water infrastructure. A top-rated agricultural pest, nutria also pose a serious risk to the state’s multi-billion dollar agricultural economy. CDFW is leading the state’s effort to eliminate nutria from the California landscape.

Nutria, furtive and primarily nocturnal, can be difficult to detect in the heavily vegetative wetland environments they prefer, particularly as trapping knocks down their numbers. Dogs can move more quickly through the wetland habitat and cover more territory than their human partners. The dogs’ responses to nutria scent – sometimes sitting, other times lying down or standing still – can alert CDFW biologists to nutria presence or let them know they need to look elsewhere.

It’s a page right out of the playbook of the federal government’s Chesapeake Bay Nutria Eradication Project, the only successful nutria eradication effort in the United States and a model and source of inspiration for California wildlife officials. That effort removed some 14,000 nutria from more than a quarter-million acres of the Delmarva Peninsula from 2002 to 2015. Nutria detection dogs joined the campaign in 2014 and proved invaluable in finding the last remaining animals. Three years after the last nutria was removed, the project still maintains a team of six nutria detection dogs and their handlers. Their primary role now is not to find nutria necessarily – but rather give biologists confidence that nutria are no longer present.

Many of the Chesapeake Bay nutria detection dogs have been Labrador mixes adopted out of animal shelters. The Labrador blood helps with the water work. The dogs’ high energy and prey drive that made them difficult household pets and forced their owners to surrender them made them ideal working dogs when given a job to do and a focus for their energy.

Star and Trigger, by contrast, have pedigreed bloodlines from proven scent-detection lineage. Still, questions surfaced at the outset of training whether the dogs would take to nutria detection work. Would Trigger, a heavy coated German shepherd, take to water work? Would Star, a bundle of Labrador puppy enthusiasm, have the attention span to stay focused on the job? Their training not only involves accurately identifying nutria scent, but also distinguishing it from that of beaver, muskrat, mink, raccoon and other birds and animals that inhabit the same wetland habitat.

It’s all positive reinforcement. Successful detection is rewarded with praise, affection and play. Star gets to make a few water retrieves of a favorite rubber ball toy. Trigger gets some toy time and a quick game of tug of war.

“They’re both doing extremely well,” said Shimek during a training break recently at the Upper Butte Basin Wildlife Area in Northern California. ”I am extremely confident these two dogs will be a big help in our eradication efforts.”

Star and Trigger are pioneers of sorts as biological detection canines. While CDFW has used canines in law enforcement work since 1989, Star and Trigger are part of two separate pilot programs to determine whether biological detection canines can support CDFW’s scientific work.

Star and Trigger’s handlers are not wildlife officers, but rather environmental scientists Harvest Vieira and Helayna Pera, respectively. Before their nutria assignment, Star was being trained to detect the nests of Western pond turtles, a Species of Special Concern in California due to declining populations. Trigger is trained to find downed deer that have been darted with tranquilizers. He can even locate errant darts from missed shots.

Both Vieira, based in Redding, and Pera, based in Sacramento, believe the nutria eradication effort is exactly the kind of high-profile project where their scent-detection dogs can shine, perhaps leading to a formalized program and additional biological detection dogs that can support CDFW’s various conservation and scientific efforts across the state.

 

 

 

 

CDFW Photos by Peter Tira. CDFW Video Courtesy of Sandra Jacks. Top Photo: From left to right: Trigger, his handler Helayna Pera, CDFW dog trainer Lynette Shimek, Star’s handler Harvest Vieira, and Star pause for a photo during a training break at the Upper Butte Basin Wildlife Area.

Categories: General
  • June 20, 2018

Birds eye view of waterways and land

Birds eye view of waterways and land masses

In the heart of California’s Sacramento-San Joaquin River Delta lies a 3,000-acre flooded island called Franks Tract.

Before humans diked and drained Franks Tract to grow potatoes, grains, asparagus and corn, the island was part of a vast freshwater marsh. Breaches in levees flooded Franks Tract in 1937, and farmers never reclaimed the island. Franks Tract today is a nexus point of many delta uses, ranging from duck hunting and bass fishing to fresh water supply for California cities and farms.

But the island is also a hot spot for invasive plants and predatory fishes, as well as a conduit for saltwater intrusion into waterways used to convey freshwater supplies to cities and agriculture in the Delta and other parts of California. For these reasons, Franks Tract is considered a strong candidate for partial restoration.

“Franks Tract is a microcosm of many of the larger problems pervading the inner Delta, said Carl Wilcox, Delta policy advisor to the director of the California Department of Fish and Wildlife. “Some native fishes are in serious decline, improving the quality of available habitat in the Delta and increasing resilience to drought and climate change could support their persistence and recovery.”

Various partners, led by CDFW, are proposing to restore about 1,000 acres of Franks Tract to tidal marsh. The proposed restoration is consistent with the Delta Smelt Resiliency Strategy, state goals for the Franks Tract State Recreation Area, and state water quality control plans for the San Francisco Estuary. The effort also aligns with the multi-agency Delta Conservation Framework and the Central Delta Corridor Partnership.

The proposed restoration could shrink waterweeds, grow fish food, create habitat for Delta smelt and other declining species, and prevent salinity intrusion into the south Delta. It may also improve recreational opportunities for residents and visitors.

Results of hydrodynamics modeling indicate the proposed restoration would provide more fresh water to the central Delta shielding regions upstream from ocean saltwater intrusion. A 2017 UC Davis survey documented year-round use of Franks Tract and surrounding channels by locals, visitors and researchers, and seasonal use by hunters, anglers and boaters. Many survey respondents were concerned about changes in access to the water and effects on the local economy and sport fishing, which is dependent on that access. The survey yielded useful information for the next, more detailed, planning and design round including a locally proposed alternative design.

“We will continue to work with stakeholders to not only address habitat and water quality priorities, but also enhance recreational and sport fishing opportunities,” Wilcox said.

A recently released report, Franks Tract Futures: Exploring Options for Multi-Benefit Restoration and Increased Resilience in the Central Delta Corridor, summarizes the technical studies and stakeholder input that’s been collected relative to the potential restoration of Franks Tract.

If approved for further development, the Franks Tract restoration proposal would enter a second phase of planning, design and environmental review with a target end date of December 2020.

CDFW Photos.

Categories: General
  • June 11, 2018

Man holding large cardboard box in front of man holding turkey.
Tim Hermansen of CDFW carries a turkey holding box to CDFW’s Levi Sousa while John Davis clears the net.

Person holding turkey while another person holds turkey foot against wooden post.
Derek Schiewek of CDFW holds a turkey while CDFW’s Laura Cockrell measures the tarsus.

Recent efforts to determine the number of turkeys on the Upper Butte Wildlife Area have been a net success.

CDFW staff and volunteers from the National Wild Turkey Federation (NWTF) began annual turkey banding efforts in 2015 to gather information about turkey demographics and movements to facilitate better management of the population and assess future hunting opportunities. Approximately a dozen volunteers and staff have since worked on this effort two months each year, in the late winter through early spring.

Captured birds are fitted with a numbered band, and their age, gender and weight are determined before they are released. The number of times a turkey is recaptured through ongoing trapping activities, or when a hunter returns a band to CDFW, provides data about the density and the movements of the birds. Approximately 20 wild turkeys have been captured each of the past four years, using air cannons that propel nets. Last year was the sole exception, as torrential storms resulted in zero captures because portions of the property were flooded and could not be traversed with trapping equipment.

“That year was very frustrating, but part of being a wildlife biologist is going with the flow,” recalled CDFW Environmental Scientist Laura Cockrell, who is involved in coordinating and facilitating wildlife surveys on the wildlife area.

This year, walk-in traps were used for the first time to supplement the traditional use of air cannons, and the final tally was 38 turkeys banded, increasing the total number banded over the course of the project to 88. This baseline data will inform decisions on how many turkey hunters will be allowed access to the wildlife area each spring.

“Our volunteers and all our staff are what makes this project successful,” Cockrell said. “Everyone completes a safety training so we can make sure the birds are handled quickly and carefully, and then it is a lot of ‘hurry up and wait’ during the trapping operations. If we did not have a dedicated crew on this project, it would not be successful. The walk-in traps allow staff to set up trapping operations in the morning, check the site throughout the day, and process birds as they are captured.”

Also appreciative of the banding efforts were turkey hunters, who had an extra “spring” in their step this year at the Upper Butte Wildlife Area.

The 2018 spring turkey hunts recently ended after 64 hunters who hunted on Upper Butte Basin harvested 35 turkeys. During the previous three spring seasons combined since spring turkey hunts began on the wildlife area in 2015, 133 hunters participated and 47 turkeys were harvested.

All the result of field conversations between CDFW staff and fall turkey hunters.

“During the fall turkey seasons some years back, hunters at the check stations would frequently ask us when we were going to offer a spring season, which we had not done before,” Cockrell said.

At the wildlife area’s Howard Slough and Little Dry Creek units, the problem was not a lack of turkeys but rather a lack of funding to hire staff to advertise, prepare, regulate and operate the extra hunts – and a lack of scientific data to support an extra hunting season.

A collaborative effort between CDFW and the NWTF solved that problem.

In 2014, NWTF applied for and received a state grant from the Upland Game Bird Stamp Fund. The grant proposal, which was spearheaded by NWTF District Biologist Kevin Vella, obtained five years of funding to support a seasonal coordinator position.

“This spring we had almost 1,800 applications for 144 open spots,” said Cockrell. “Our hunters really appreciate the opportunities that the spring turkey hunts provide. We frequently hear after a hunt what an amazing time they had out in the field and how much they enjoyed their time on the wildlife area. One of our hunters this season was so excited because he was able to harvest a nice turkey at his very first hunt!”

All photos © National Wild Turkey Federation, all rights reserved. Top Photo: Tim Hermansen of CDFW holds a turkey while Laura Cockrell of CDFW measures its beard with calipers.

Categories: General
  • May 31, 2018

Diver underwater in black diving suit holding underwater writing tablet underwater in kelp forest
WARC diver Shelby Kawana assesses habitat at one of the CDFW red abalone stocking sites located off the coast of southern California.

Diver underwater in black diving suit holding a large grid made from PVC pipes and wire in kelp forest
WARC diver Armand Barilotti assesses habitat at one of the CDFW red abalone stocking sites located off the coast of southern California.

Curled up octopus hiding underwater
Octopus are a top abalone predator and therefor pose a threat to newly stocked juvenile red abalone populations. Researchers catch and relocate octopus when they are found hiding in crevasses near stocking sites.

Abalone attached to a rock
A rediscovered stocked red abalone was found clinging to the underside of a rock during a one year post stocking survey.

Harvesting abalone for dinner used to be as fundamental to a Southern California lifestyle as fish tacos and flip-flops. But by 1998, a combination of overfishing and disease led to the closure of all abalone fishery south of San Francisco. By 2001, the white abalone was listed as an endangered species because populations continued to decline despite protection from fishing pressure. Population numbers are so low today that the only option for recovery is believed to be through a robust captive breeding and stocking program.

Scientists from the California Department of Fish and Wildlife (CDFW) White Abalone Recovery Project and their partners in the White Abalone Recovery Consortium (WARC) are working to bring back the iconic white abalone from the brink of extinction. Since 2016, CDFW and partners have been working to actively restore abalone populations through stocking of young captive-reared abalone. Successful stocking is the critical next step to reestablishing self-sustaining wild populations of this culturally and ecologically important mollusk. The early stocking studies have aimed to perfect the methods that will be used to restore wild white abalone populations in the future by using red abalone as a test case. Red abalone, a sister species of the white abalone, lives in the same deep kelp forest habitats, and their populations in Southern California have also been very slow to recover.

Every few months, scientific divers on board the CDFW research vessel Garibaldi wrestle into thick neoprene wetsuits and load heavy steel tanks onto their backs in order to check on the stocked abalone. As the divers descend deeper into the kelp forest, they enter the world of the white abalone. Sunlight streams through the towering giant kelp, briefly illuminating the shiny sides of the small fish taking cover in the kelp blades. Lobsters and octopuses are tucked into the crevices of rocks, and abalone and urchins shelter in the shadows. Many of those abalone are adorned with small brightly-colored numbered tags that identify them as the new additions to the neighborhood. After a few months in the wild, the stocked abalone can show an extensive amount of growth which speaks to the quality and abundance of resources in their new habitat.

Since restoration stocking began in 2016, the partnership has stocked close to 10,000 red abalone off the coast of southern California. These studies are helping scientists understand how stocked abalone interact with their new environment in the wild. Researchers are increasing the effectiveness of future stocking work by teasing out the risk factors that abalone face in their new environment. For multiple years after releasing the abalone, divers track the number and identity of each abalone, and assess the ecosystem health and predator abundances at each site. The divers also collect any abalone shells encountered to determine the effects of different predators at each site through time.

Octopuses, lobsters, sea stars and fish are all major predators of the young abalone, and care is taken to introduce the abalone during times of the year when the predators will be least abundant. All of the data from these early studies are aimed at lessening the risks that stocked abalone face, and to improve long-term growth and survival.

The WARC understands that abalone are at the heart of coastal California’s identity and culture. The return of red and white abalone to the wild marks the beginning of a new chapter in the love story between California and this amazing mollusk. This is true for the ecosystems that rely on them as well as for the humans that cherish them. Please stay tuned for updates on the lessons learned from these studies, and plans for upcoming white abalone stocking work!

For more information, please visit the following pages:

CDFW Photos. Top Photo: Newly tagged red abalone that are ready to be released into the ocean during a WARC stocking study in 2016.

Categories: General
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