Recent accomplishments of CDFW's scientific community
The Pacific herring – much like squid and anchovy – is an important forage fish that supports a commercial fishery and provides a prey source for all manner of fish and wildlife, including whales, seals, sea lions, sturgeon, salmon, pelicans and numerous other species of birds and invertebrates.
The largest population of Pacific herring in California spawn in San Francisco Bay, and since 1972, CDFW has been responsible for monitoring and managing their numbers. CDFW uses annual vegetation dive surveys and spawn (herring eggs) surveys to calculate a population estimate each year. CDFW also uses commercial fishery and mid-water trawl survey information to look at the composition and general condition of the spawning population.
CDFW has just completed and posted online the 2016-17 San Francisco Bay Season Summary for the Pacific herring fishery. The good news is that the spawning population, estimated at 18,300 tons, is up slightly from the 2014-15 and 2015-16 seasons. But it is still far below the historical average of 49,400 tons. Less than ideal ocean conditions are cited for the below-average numbers.
CDFW closely regulates the commercial Pacific herring fishery in the San Francisco Bay, setting quotas, season dates and using the commercial catch data to help further analyze the size, age and condition of the spawning population. Typically about six inches long, the fish primarily are harvested for their roe, which is prized in Japan. CDFW maintains a blog on the species called the Pacific Herring Management News.
“We’re getting more accurate and precise numbers for harvest than we’ve ever had before, which is critical for calculating the tag quota for the next year and conserving our deer populations for the future,” said Stuart Itoga, a senior environmental scientist with CDFW and the state’s deer program coordinator.
Until recently, accurate deer harvest data had proved elusive. Prior to 2015, only successful California deer hunters had to report their take and only about 30 percent of those actually complied. CDFW supplemented the harvest data with numbers collected from game processing facilities, an inefficient process that still left an incomplete picture.
“It’s Wildlife Management 101,” Itoga said. “You have to know what your population is, what’s coming in and what’s going out. We needed to have better numbers.”
Following the mandatory reporting requirement in 2015, submittal rates for deer tag harvest reports jumped to 50 percent. In 2016, a $21.60 non-reporting penalty took effect, which applies to the purchase of future tags, and boosted reporting to the all-time high.
Mandatory deer tag reporting data is just one of a number of new tools that has CDFW deer biologists excited about their ability to better assess California’s deer herds.
An innovative DNA study of deer feces promises to give biologists new information about the size and characteristics of the state’s deer population.
CDFW has also greatly expanded the use of deer tracking collars, thanks to improved technology. Since 2016, CDFW has affixed the relatively lightweight, remotely programmable, GPS tracking devices on 350 deer to learn more about their preferred habitat, in-state and out-of-state migration routes and sources of mortality other than hunting. Advanced camera technology also promises to improve the data collected from CDFW’s aerial and ground-based population surveys. A new computer model is being developed to incorporate all of these new data sources into more sophisticated, accurate and precise deer population estimates.
“It’s really an exciting time to be doing this type of work,” Itoga said. “We’ve always used the best available science, but with technology moving at the pace it’s moving now, we have tools available to us now that we didn’t have even five years ago.”
Management changes can happen more quickly as a result. For the upcoming 2017 deer hunting seasons, for example, deer tag quotas were cut in half in three highly desirable, Eastern Sierra X Zones – X9a, X9b and X12 – as a result of new data and field work that showed that migratory deer in these areas suffered from the long, intense winter.
“Winter survival was poor,” Itoga said. “Our hope is that if we reduce the harvest this year, the populations will have a chance to rebound and increase next year.”
Banded black brant feeding on eelgrass
Volunteer John Roser in the field at Morro Bay
Flock of black brant in flight above Morro Bay
Black brant in Morro Bay
John Roser began hearing the stories shortly after he moved to Los Osos, San Luis Obispo County, on the shores of Morro Bay in the mid-1990s.
Longtime birders, waterfowl hunters, biologists and other coastal residents were all saying the same thing: It seemed fewer black brant were showing up on the bay each winter.
The coastal sea goose is a cultural icon of the area, the signature species of the Morro Bay Winter Bird Festival and a temporary visitor welcomed by locals as the geese arrive each fall from their summer breeding grounds in the Arctic. When the geese are present in big numbers, you can hear their cacophony almost anywhere on the bay from November through April or until the warm environs of Baja California lure the birds farther south on their migration.
Roser, who holds a degree in biology from Cal Poly San Luis Obispo and spent 25 years as an environmental educator, set out to see if the old-timers’ stories were true. For the past 21 years, he has provided CDFW and brant biologists throughout the Pacific Flyway with their most credible and reliable source of data on wintering brant in Morro Bay.<
“I’m retired, and I wanted to take on a volunteer project that would make a difference in this community,” Roser said of his motivation. “I wanted to create a Morro Bay specific data set significant enough that it would be valuable in brant studies and research across the Pacific Flyway.”
Roser’s retirement project has led him on a brant-like odyssey.
He banded brant one summer in Alaska, worked in Humboldt Bay with leading brant researcher Jeff Black and his Humboldt State University graduate students, and traveled to Baja California to help biologists read bands on birds at the extreme end of their southern range. Much of Roser’s winter observations take place at CDFW’s Morro Bay Wildlife Area.
“John is our go-to guy on the ground in Morro Bay for sure,” said Melanie Weaver, the head of CDFW’s Waterfowl Program. “We only have two employees in our program, myself included, so we depend on regional staff and volunteers like John to help compile survey data. John is part of the local community, he cares, and he is close to the resource.”
The data Roser supplies are incorporated into CDFW’s Mid-winter Waterfowl Survey, which is used to set hunting regulations for the following waterfowl season.
What attracts brant to Morro Bay is the same thing that prompts the birds to stop at other coastal bays along their southward migration: eelgrass. The underwater seagrass grows in shallow marine environments and is the birds’ primary food source.
Roser’s initial research in 1997 confirmed the reports he was hearing: The wintering brant population in Morro Bay had declined significantly and corresponded with a crash in eelgrass acreage in the bay.
While CDFW surveys from the 1930s through 1960s documented Morro Bay’s wintering brant population as high as 11,800 birds, Roser’s first survey in 1997 recorded a population high of fewer than 700 birds.
The eelgrass crash in the mid-1990s was temporary and well-understood, caused by an influx of sediment from a fire-ravaged landscape, a deluge of freshwater from a rainy year and warming El Nino ocean conditions. As environmental conditions normalized in subsequent years, the eelgrass rebounded, and the brant returned. Roser counted a population high of 4,600 birds in Morro Bay in 2001.
The story since then, as told in Roser’s annual reports to CDFW, is of another dramatic crash in eelgrass acreage in Morro Bay and a corresponding drop in the numbers of brant wintering there. Unlike the eelgrass crash of the mid-1990s, the latest decline has been more persistent and perplexing.
Biologists measure Morro Bay’s eelgrass acreage each year. Eelgrass spanned 344 acres as recently as 2007 but had dwindled to just 14 acres by 2017. Not surprisingly, Roser’s 2016-17 brant survey recorded a population high of just 319 birds and a low of 43. Roser’s brant-use-day metric has fallen by 90 percent since the nearly 500,000 brant use days he recorded in 2001. In the past five years, brant use days have measured around 50,000 a year. Money from the purchase of the California duck stamp-validation, required to hunt waterfowl in California, is funding research into the eelgrass decline along with restoration efforts.
In addition to fewer numbers of brant frequenting Morro Bay, Roser has noticed behavioral changes in the birds that still show up. Increasingly, the brant are foraging on secondary food sources that include salt marsh vegetation and green algae species such as sea lettuce with eelgrass in short supply.
Roser takes some solace that the overall Pacific Flyway brant population is holding steady if not increasing, estimated between 130,000 to 165,000 birds. Roser says waterfowl biologists are seeing flyway-wide changes in brant behavior that they suspect may be linked to climate change.
Fewer brant are migrating to Mexico for the winter. More are remaining in Alaska and their northern range throughout the year as warming Arctic conditions require fewer calorie demands and less ice exposes more eelgrass. Ten years ago, less than 10 percent of the population wintered in Alaska. By 2017, almost 40 percent of the Pacific Flyway population spent the winter there.
“This bird is tied to Morro Bay, our culture and our identity,” Roser said. “A robust wintering brant population needs abundant eelgrass beds. Eelgrass needs a healthy bay and watershed. Our actions as stewards of Morro Bay really do reverberate across the globe.”
CDFW photos: courtesy of John Roser
Top photo: Pair of black brant on Morro Bay
Once on the verge of extinction in the lower 48 states, the bald eagle (Haliaeetus leucocephalus) has made a remarkable comeback in California. Management programs and protective laws (most notably, a ban on the pesticide DDT) have had a profoundly positive effect on both the reproductive success and survival rate of the species. Its breeding range is rapidly expanding and today, bald eagles can be found in 42 of California’s 58 counties, rebounding from a low of eight counties in the mid-1990s.
Though the U.S. Fish and Wildlife Service removed the bald eagle from its list of threatened and endangered species in 2007, the species remains endangered under California state law, and data is constantly being gathered and analyzed to support ongoing population recovery efforts. But studying California’s eagle population is more difficult than one might think. Although reports of single eagle sightings are a useful tool for determining range expansion, they are often inconsistent and inappropriate for estimating the overall population. A better method is documenting bald eagle observations and breeding territories and monitoring them over time. To do that, CDFW relies heavily on survey data submitted by other agency partners, researchers, consultants and the general public.
According to CDFW’s Statewide Raptor Coordinator Carie Battistone, there are two ways for members of the public to contribute to this important database.
Single observations can be reported using the California Natural Diversity Data Base (CNDDB) Online Field Survey Form. This may include breeding (for example, a nest location or a pair constructing a nest) or nonbreeding (a single bird foraging or perched) observations. For all data submissions, the more information that is provided to the CNDDB on population size, site condition, threats, etc., the better.
People who have more time (or experience in long-term monitoring) should use the Bald Eagle Nesting Territory Survey Form (PDF). This form is typically used by observers who monitor a nest frequently during an entire breeding season (from when a pair arrives at or builds a nest to when the young fledge). The information recorded on this form allows CDFW to determine nest success and productivity. Observers take notes during each survey they conduct, including behavior, the number of adults and young seen, number of fledglings, predation events, nest conditions, etc. Observers should closely follow the survey instructions and keep their distance from the eagles so as to not disturb breeding activities.
Various other types of data are tracked in CDFW’s databases, including the coordinates of observation or nest location, land ownership, the number of nests within a territory, the nest-tree type and nest condition, the number of surveys at a territory or nest, the number of adults or sub-adults seen, the number of eggs laid, the number of young fledged, predation events associated with an observation, general behavior, and other pertinent information.
“The more information we have on nest location, behaviors and breeding activities, the easier it is for us to decipher how eagles are using their territory and what the status is at any given site,” said Battistone.
According to Battistone, 371 nest sites have been reported and entered in CDFW’s bald eagle database to date (early 1990s through 2016). This data, however, is incomplete -- not all nests are reported or known, and of the nests that are entered in the database not all are surveyed every year.
CDFW receives regular reports of bald eagle sightings throughout the state during both the breeding and nonbreeding season, and as the population continues to grow and expand it is expected the number of sightings will continue to increase.
“Because the bald eagle population seems to be increasing in California, reports of new nests are not entirely surprising,” Battistone said. “However, to get a better understanding of the extent of the population increase and expansion throughout different regions of California, it is helpful to have the most complete dataset possible. We encourage and appreciate participation from the public!”
Bald eagle photos used with permission, courtesy of Marcia Grefsrud.
CDFW Seasonal Aid Katie Schroyer determines the age of a dove by examining its wing
A banded mourning dove at a CDFW trap site in northern California
Age and sex data are recorded before the bird is banded and released.
A large kennel trap can catch more than 30 birds at a time.
As the second half of California’s split dove season kicks off, dove hunters may put more than birds in their bags. They may harvest a bird with a band on its right leg – thus getting an opportunity to contribute important data that will help guide future management efforts.
Since 2003, California has been an active partner in a nationwide assessment of mourning dove populations. California is one of 39 states that currently participate in dove banding. During the months of July and August, trained biologists and volunteers trap and band doves throughout the state. The banding of migratory birds requires a Master Banding Permit issued upon approval of a study application by the U.S. Geological Survey. All banders must pass an annual training to participate and are then issued a sub-permit.
Mourning doves are so widely distributed that banding operations can be – and are – located almost anywhere, from rural locations to urban backyards. Larger operations located on Wildlife Areas, ranches and open desert sites may employ the use of a large kennel trap capable of trapping 30 or more birds at a time, while smaller operations (“backyard banders”) use small Kniffin traps that catch just one or two birds at a time.
When a bird is banded, age and sex data are recorded. This information, along with capture location, date, bander name and corresponding band number, becomes part of a massive database managed by the USGS’s Bird Banding Laboratory. The mourning dove banding data is available to any interested party, but is mainly used by the U.S. Fish and Wildlife Service (PDF), university scientists and state agency scientists to analyze and estimate annual survival, harvest rates, recruitment and abundance.
The resulting analysis is used by wildlife managers in setting annual hunting regulations. For instance, in 2015, the USFWS increased the take of mourning doves in the Western Management Unit (which includes the states of California, Oregon, Washington, Idaho, Nevada, Utah and Arizona) from a daily bag limit of 10 to 15. The California Fish and Game Commission followed suit, also increasing the possession limit from two to three times the daily bag limit, in order to accommodate hunters on multi-day hunting trips.
If you harvest or find (encounter) a banded bird, CDFW asks that you report the number directly to the Bird Banding Laboratory. This can be done online at www.reportband.gov, or by calling (800)327-2263. When reporting an encounter you will be asked for the band number and basic information about where and how you obtained the band.
The person reporting is allowed to keep the band, and will receive a certificate with the details about where, when and by whom the bird was banded.
The USGS Bird Banding Lab is the keeper of banding data for both the US and Mexico. As of September 18, 2017 and since 1960, the BBL has received over 64 million banding records. Since the inception of the North American Bird Banding Program, the BBL has received over 4 million encounter records. On average, over the past decade, the BBL received 1.2 million banding and 87,000 encounter records per year.
For more information about mourning dove banding, including the 2017 Mourning Dove Harvest Strategy, visit the Doves and Pigeons page on the FWS website.
CDFW photos by Kloey Helms
Featured photo: CDFW Seasonal Aid Katie Schroyer determines the age of a dove by examining its wing.
The latest issue of California Fish and Game, 103-3, makes a significant contribution to the body of research related to longfin smelt in California. A paper titled, “Historic and contemporary distribution of Longfin Smelt (Spirinchus thaleichthys) along the California coast (PDF)” analyzes and presents observation data for this species from a variety of published and unpublished sources dating from 1889 to 2016. This anadromous fish, which is listed as threatened under the California Endangered Species Act, has been documented in a diverse range of habitats, including coastal lagoons, bays, estuaries, sloughs, tidal freshwater streams and nearshore habitats. In addition to providing a comprehensive look at the existing information available for longfin smelt along the California coast, this paper identifies additional information needed to improve management and enhance recovery of the species within the state.
In “Distribution and derivation of dabbling duck harvests in the Pacific Flyway (PDF),” the authors look at abundance, banding and harvest data from throughout the Pacific Flyway and other important source areas in the Central Flyway to estimate the distribution and derivation of Pacific Flyway dabbling duck harvests during 1966−2013. The Pacific Flyway has long been considered an important wintering area for dabbling ducks. Better knowledge of the origins of these birds could assist in both harvest and habitat management.
The authors of “Distribution of Amargosa River pupfish (Cyprinodon nevadensis amargosae) in Death Valley National Park, CA (PDF)” endured harsh environmental conditions to document the occurrence of Amargosa River pupfish along the lower Amargosa River drainage where the species has not been previously documented. The downstream-most location of Amargosa pupfish captured in this study extends the previously recorded geographic range approximately 49 river km. The findings not only determine the distribution of Amargosa River pupfish within Death Valley National Park, but will help identify suitable locations at which to establish long-term monitoring sites.
California Fish and Game has published high-quality, peer-reviewed science for the past 103 years, making important contributions to the understanding and conservation of California’s wildlife.
Cover photo courtesy of Gerald and Buff Corsi © California Academy of Sciences.
The California Department of Fish and Wildlife (CDFW) has completed its annual waterfowl breeding population survey.
Mallards, gadwall and cinnamon teal comprised 54 percent of the ducks observed, down 30 percent from last year. The number of mallards decreased from 263,774 to 198,392 (a decrease of 25 percent) and total ducks decreased from 417,791 to 396,529 (a decrease of five percent).
The most notable decrease occurred in the Sacramento Valley area, where mallards were estimated at a record low of 31,000 (73 percent below the long-term average).
Given the abundant precipitation, one might expect the numbers to be higher. In some parts of the state, it did indeed increase available habitat (uplands and ponds). But in many areas, last winter’s heavy rains largely resulted in deep, fast-flowing water, which is not ideal for dabbling ducks. Other reasons for low duck observations could include winter flooding of nesting habitat that normally remains dry, the late-season flooding of the rice fields in the Sacramento Valley and the conversion of rice fields and pastures to tree crops.
CDFW biologists and warden pilots have conducted this annual survey using fixed-wing aircraft since 1948. This year’s survey was conducted from April 3 through May 4 in the Central Valley, and May 9-10 in northeastern California. The population estimates are for the surveyed areas only, which include the majority of the suitable duck nesting habitat in the state. Surveyed areas include wetland and agricultural areas in northeastern California, throughout the Central Valley, the Suisun Marsh and some coastal valleys.
The full Breeding Population Survey Report can be found at www.wildlife.ca.gov/conservation/birds/waterfowl.
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.
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