Scientific Research Grants
We may be a small Audubon chapter but we are serious supporters of conservation science. For 2022, our Scientific Grants Committee funded the following projects in the amount of $36,182, thanks to generous donations from our membership.
Institute for Bird Populations: Tracking Great Gray Owls to advise habitat management in Yosemite National Park
This project will tag and track Great Gray Owls in Yosemite National Park to improve foraging habitat and to make roadsides less attractive to the owls, thereby reducing vehicle collisions. Great Gray Owls nesting in the Sierra Nevada constitute a putative subspecies (S. n. yosemitensis) that is isolated from the rest of the North American population and likely comprises fewer than 100 breeding pairs. It is listed in the California Endangered Species Act as SENSITIVE.
Project Leader: Ramiro Aragon
Lower Perrazo Meadow
Institute for Bird Populations: Surveying birds for pre- and post-restoration monitoring at meadows in and near the Little Truckee River watershed
These meadows are a mix of sites that have been recently restored, are in the planning phase to be restored, or are for now serving as controls that will help evaluate the effects of restoration at the restored sites. This is a multi-year effort to 1) establish pre-restoration metrics of meadow bird communities prior to restoration, 2) use pre-restoration data to advise on bird-friendly restoration design elements, and 3) monitor post-restoration bird communities to learn lessons for better meadow restoration.
Project Leader: Helen Loffland
Female Williamson's Sapsucker
Institute for Bird Populations: Understanding molt patterns and improving age determination criteria in Williamson's and other sapsuckers to aid conservation
This project will investigate and describe molt patterns in the four Sphyrapicus sapsucker species, Williamson's (S. thyroideus), Yellow-bellied (S. varia), Red-naped (S. nuchalis), and Red-breasted (S. ruber) Sapsuckers. The primary goal of this analysis will be to investigate molt patterns of these four species as related to modeling of age structure and the application of results to the conservation needs of these four species. A second goal of this study will be to compare molt patterns among the four sapsucker species, each of which has differing habitat requirements, migration regimes and conservation requirements, to better understand the evolution and ecological drivers of molt strategies in this group of species.
Project Leader: Peter Pyle
Color banded Snowy Plover
San Francisco Bay Bird Observatory: Color Banding Western Snowy Plovers to Assess Survival and Dispersal Patterns in the South San Francisco Bay Area
SFBBO's continuing banding efforts achieve the following objectives: 1) estimate chick fledging rate per male as defined in the USFWS recovery plan (USFWS 2007), 2) determine juvenile overwinter survival and recruitment into the breeding population, 3) track unbanded brood survival if the adult is banded, 4) determine demographics such as site fidelity, natal fidelity, and habitat use throughout SF Bay. The Western Snowy Plover is listed as THREATENED by the U.S. Fish and Wildlife Service.
Project Leader: Ben Pearl
Dr. Robert Meese for research on Tricolored Blackbirds and funding for maintenance of the Tricolored Blackbird portal
Tricolored Blackbird male in flight
This project conducts research on Tricolored Blackbirds throughout California, with an emphasis on detecting, monitoring, and determining the fates of colonies in the upper San Joaquin and lower Sacramento Valleys, the Coast Ranges, and the Central Coast. Since 2007, Dr. Meese has been banding birds at their breeding colonies and at one non-breeding location. He has banded over 104,000 Tricolored Blackbirds (current to November 2021,) from southern Kern County to northern Colusa County, and has recaptured 2,900 of the birds he has banded. Dr. Meese collaborates with Cornell University researchers to analyze the recapture data to estimate life history parameters and to document patterns of movement. The Tricolored Blackbird is listed as THREATENED by the California Endangered Species Act.
Dr. Robert Meese: Research on Tricolored Blackbirds and funding for maintenance of the Tricolored Blackbird portal.
This project conducts research on Tricolored Blackbirds throughout California, with an emphasis on detecting, monitoring, and determining the fates of colonies in the upper San Joaquin and lower Sacramento Valleys, the Coast Ranges, and the Central Coast. Since 2007, Dr. Meese has been banding birds at their breeding colonies and at one non-breeding location. He has banded over 104,000 Tricolored Blackbirds (current to November1, 2021,) from southern Kern County to northern Colusa County, and has recaptured 2,900 of the birds he has banded. Dr. Meese collaborates with Cornell University researchers to analyze the recapture data to estimate life history parameters and to document patterns of movement.
The Tricolored Blackbird is listed as THREATENED by the California Endangered Species Act.
Institute for Bird Populations: Determining breeding status of Willow Flycatchers discovered in low-elevation areas of the Sierra Foothills.
This project was a follow up on recent anecdotal observations of Willow Flycatchers displaying territorial behaviors in low-elevation portions of the northern Sierra Nevada Foothills, a region where the species was thought to have been extirpated decades ago. Surveys were conducted to determine the locations and types of habitat being used by these flycatchers and to determine whether the sites were being used as migration stopover sites or for breeding. Although no direct evidence of nesting was found, the results suggest that wetland habitat throughout the study area is being used primarily by migratory, rather than nesting, Willow Flycatchers, and that a large proportion of the available appropriate habitat across the region surrounding our study areas is likely being used by migrating flycatchers. As with many passerine species, migration seasons may be the periods of highest mortality for Willow Flycatchers yet also the least studied, and with the least management emphasis. We therefore suggest wetlands throughout the region may be an important resource for migrating Willow Flycatchers, and should be considered when making conservation decisions for the species in California.
Institute for Bird Populations: Molt patterns and age determination in western Willow Flycatchers
This ongoing project seeks to investigate and describe currently unknown molt patterns of Willow Flycatchers breeding in the Sierra Nevada and throughout western North America. Knowledge of these molt patterns will lead to more accurate age determination criteria for target populations, which will enhance understanding of the species’ demography and habitat selection.
Hydrologic restoration and persistence of Willow Flycatchers at Sierra Nevada meadows:
manuscript preparation
This grant was to help finalize preliminary data analysis and prepare a manuscript for submission to a scientific journal detailing findings about the response of Willow Flycatchers to hydrologic restoration at sites along the Little Truckee River. The manuscript underwent peer review and the paper was officially accepted by the journal Western Birds. It is now in press, and will be published in the February 2022 issue of the journal.
Empire Mine Bird Monitoring Program
At the site, we monitor birds through bird banding as well as censuses. Data will be used to inform conservation by estimating species composition, abundance, and demography (through survival and reproductive rates). Long-term monitoring is the most-widely accepted method for measuring trends in bird populations, and an increase in coordinated surveys of North American birds is recommended by the U.S. North American Bird Conservation Initiative Committee. The monitoring station also provides public education to local school groups through field-based monitoring demonstrations.
The primary objectives of this ongoing project are to:
- perform long-term monitoring of species composition, abundance, and vital rates
- provide educational opportunities to schools and other Foothill community members to improve understanding of birds and foster interest in the conservation and improvement of bird populations and their habitats
- provide a unique venue for universities or other entities to conduct Foothills-based avian research
Gold Country Avian Sciences Banding project
Institute for Bird Populations field bird studies
Institute for Biodiversity Burrowing Owls
University of California Black Rail studies
Dr. Robert Meese for research on Tricolored Blackbirds and funding for maintenance of the Tricolored Blackbird portal
John Muir project Black-backed Woodpecker
University of California Black Rail studies
Gold Country Avian Sciences Banding project
Institute for Bird Populations field bird studies
Institute for Bird Populations field bird studies
Northwest Hydraulic Consultants Tricolored Blackbird study
Point Blue Conservation Science bird climate studies
University of California Black Rail studies
Gold Country Avian Sciences Banding project
Institute for Bird Populations Great Gray Owl project
Institute for Bird Populations field bird studies
Northwest Hydraulic Consultants Tricolored Blackbird study
University of California Black Rail breeding in foothills
Lake Davis Flammulated Owl Study
This is the final year of work conducted by David Arsenault on Flammulated Owls that we have supported for 4 years.
The project's main goal is to develop conservation strategies for Flammulated Owls occurring on national forest in the Sierra Nevada by studying populations around Lake Davis. To reach that goal, our objectives are to:
Collect information on and monitor Flammulated Owl populations at Lake Davis;
Determine the effect of Defensible Fuel Profile Zones on Flammulated Owl populations;
Study habitat use to provide management guidelines for forest service and other land managers to conserve owl populations;
Conduct outreach and education regarding owls and cavity- nesting birds;
Involve student interns to help train the next generation of conservationists.
Geolocator Research on Sierra Nevada Swainson's Thrush (continuing)
This project is being conducted by Will Richardson, PhD, of Tahoe Institute for Natural Sciences and 2016 will be the final year.
Over the past century, Swainson's Thrush (Catharus ustulatus) has undergone a significant range contraction, starting in the south and gradually progressing northward, to where the species has quietly become one of the most alarmingly and perplexingly rare species breeding in the Sierra. We have only anecdotal evidence to draw from, but by all accounts (many of which have proven quite trustworthy), Swainson's Thrush was a historically common, albeit locally and discontinuously distributed, breeding summer resident throughout most of the Sierra Nevada. In Beedy and Granholm's 1985 field guide, Discovering Sierra Birds, they open the Swainson's Thrush account by stating 'The disappearance of the Swainson's Thrush from Yosemite Valley is one of the unsolved mysteries of Sierran ornithology', and almost 30 years later these declines have remained largely unaddressed by the scientific community.
Given the apparent abundance of intact, suitable breeding habitat, loss of winter habitat is the prime suspect in these declines. The Tahoe Institute for Natural Science (TINS) has partnered with the Point Blue Conservation Science to use light-level-logging geolocators and GPS loggers to determine where these birds migrate and spend their winters. Point Blue already has had success with this innovative technique on coastal Swainson's Thrush, whose populations remain stable. Researchers in British Colombia also have demonstrated migratory differences in populations from that province using this technology, and preliminary results from four of the geolocators recovered from 2014 indicate that birds from the Ward Creek population winter in northern Colombia, and thus belong to the eastern migratory population. It remains to be determined where Strawberry Creek (just west of the Sierra crest) and Plumas Co. birds migrate.
Despite the rarity of this species, we have had terrific capture and deployment success over the previous two seasons, putting units on a total of 50 birds between Tahoe and Plumas sites (thanks in large part to generous donations from SFAS), and we managed to recover four of seven units from our 2014 Ward Creek deployments. Due to the strong migratory connectivity within populations demonstrated in the previous studies, small sample sizes should be sufficient for population-level inferences. However, the more units we can retrieve, the stronger our confidence in interpreting the geolocator data, the more likely we are to capture variation should it exist, and the more likely we can retrieve GPS units which will give us precise location data for those individuals. We believe this may be the first study to employ both technologies on a migratory passerine. Therefore, we will do our best to retrieve as many units as possible in the 2016 season. With 8 units from 2014 still possibly retrievable, and an additional 38 from 2015 (17 of which were deployed at Tahoe), we have great odds of recovering many units in 2016. However, 2016 also represents our only opportunity to recover a relatively large number of data logger units. This grant request is for funding to support target-netting in the Tahoe sites for the purpose of retrieval of geolocator and GPS units. Point Blue will be responsible for funding the retrieval of units at the Plumas Co. sites, and we are seeking additional funding from other sources to help support the labor-intensive analyses of those data and manuscript preparation and publication.
Institute for Bird Populations: Willow Flycatcher Colonization of Restored Meadows
Many territorial birds aggregate their territories near conspecifics (others of the same species). Willow Flycatchers are believed to use the presence of conspecifics as a means of identifying the intrinsic quality of habitat patches. When settlement at a given site is a function of the presence or density of conspecifics, populations may fail to re-establish in high quality habitat even after otherwise successful habitat restoration, simply because the necessary cues to breed at a location (other singing birds) are absent. This behavior therefore has significant conservation implications for small or declining populations such as the Sierra Nevada Willow Flycatcher population.
Willow Flycatchers have been extirpated from much of their range in California. At many historically occupied locations, current absence of the species likely reflects degraded habitat quality. However, where otherwise successful meadow restoration has occurred, failure of the species to reestablish itself may be a result of a behavioral unwillingness to settle in currently unoccupied meadows despite dramatic improvements in habitat condition. In 2007 we conducted a small pilot study which suggested a positive response of Willow Flycatchers to song broadcasts. In the proposed project, we will build on our past pilot study to implement and more robustly assess conspecific attraction as a restoration tool for encouraging Willow Flycatchers to recolonize restored habitats where they formerly nested, and may now have the potential to thrive again.
We will apply the restoration tool of conspecific attraction at 5-8 sites that have either been restored, or have a history of breeding flycatchers in the recent past and still support apparently high quality habitat despite currently being unoccupied. Sites will be within the high priority zones identified by Loffland et al. We will also complete Willow Flycatcher surveys at a subset of other locations identified as information gaps by Loffland et al., with a special emphasis on restored meadows within the Sierra Nevada. We will use established conspecific attraction protocols at 5 to 8 restored and/or historically occupied sites determined to be currently unoccupied by Willow Flycatchers based on surveys we conducted in 2015 or on other recent surveys. We will also monitor 5-8 control sites where vocalizations will not be broadcast. We will apply this protocol at experimental and control sites during May through July, 2016.
At each experimental site (meadow), we will play prerecorded vocalizations of Willow Flycatchers on portable broadcast devices, spaced at least 200 m apart (2 – 3 devices per meadow). Vocalizations will not be played at the control sites. At the experimental sites, vocalizations will be played at a volume of approximately 80 db from 04:00 to 10:30 daily throughout the settlement period and the breeding season (May through July). We will mount the broadcast devices on platforms approximately 2 m above the ground, with a solar panel or battery powering the system. Over the course of each morning the broadcast devices will play recordings that include approximately 50 minutes of flycatcher song, 4 minutes of alarm calls, 10 minutes of silence, and 10 minutes of songs of other species that co-occur with flycatchers, such as Yellow Warbler, Lincoln’s Sparrow, and Song Sparrow. We will include the silent periods and heterospecific songs to prevent the flycatchers from habituating to the playbacks. Vocalizations will be divided into tracks approximately 1 minute long. The broadcast unit will play the vocalizations in random order, playing each track once before repeating.
We will visit each site approximately once per week (more if time permits) throughout the breeding season and record the locations of any Willow Flycatchers seen or heard. During these visits we will slowly walk through the site and stop for 5 minutes every 100m to watch and listen for Willow Flycatchers. Territory locations will be recorded using GPS, and breeding status will also be determined based on behavioral observations or incidental detections of nests. We will also survey a subset of additional meadows identified as having gaps in Willow Flycatcher occupancy data using the Bombay et al. (2003) survey protocol.
Foothill Tricolored Blackbird Breeding Population Survey
Dan Airola will co-ordinate this survey in 2016
The project will expand on 2014 and 2015 breeding surveys for Tricolored Blackbirds in the lower Sierra Foothills, conducted under Dan Airola’s leadership. Funding will support hiring of 2 part-time area coordinators to assist Dan in conducting surveys and managing volunteer surveyors; to identify and quantify nesting colonies; and determine reproductive fates in the northern, central, and southern foothills. A major priority is to expand the survey area extent and intensity in the southern foothill counties (Merced, Mariposa, Madera, Fresno, and possibly Kern and Tulare), to evaluate responses to expected habitat recovery under drought recovery conditions.
Project goals are as follows:
Acquire a more complete estimate of the size and distribution of the breeding Tricolored Blackbird population in the lower Sierra Nevada foothill grassland region from Butte County south to Fresno County (and possibly Tulare and Kern counties).
Assess potential recovery of southern foothill nesting habitat and populations in response to increased El Nino precipitation (Merced, Mariposa, Madera, and Fresno counties).
Identify areas of suitable foraging habitat that are lacking nesting habitat and could be enhanced to increase the breeding population, especially in the southern Sierra foothills.
Provide colony distribution and population data to incorporate with the Audubon CA/UC Davis habitat mapping study, to identify responses of the species to various amounts of nesting and foraging habitat and priority areas for habitat enhancement
Acquire more robust data on reproductive success in representative foothill colonies, and
Involve Audubon chapter representatives in survey efforts to increase knowledge and commitment to Tricolored Blackbird conservation
Field methods will be similar to those used successfully in past surveys, involving:
Identifying suitable Tricolored Blackbird habitat (at a broad scale based on foraging habitat);
Identifying past breeding sites;
Identifying public roads within suitable habitat;
Having volunteers and project staff conduct surveys of past breeding sites and suitable habitat to identify breeding colonies;
Conducting follow-up surveys to identified colonies to assess numbers, persistence, and whether colonies successfully produced young; and
Conducting more intensive monitoring at a subset of colonies where access is available to determine colony productivity (average number of young produced per nesting female).
Data will be summarized in spreadsheets, subjected to statistical analysis, as appropriate, and written up for publication in a format similar to past studies.
Continued Support of Flammulated Owl Study
We increased financial support for nest boxes and recapture effort of the owls.
The Flammulated Owl is listed as a U.S. Fish and Wildlife Bird of Conservation Concern, a California Partners in Flight focal species, and a sensitive species in some national forest regions. Flammulated Owls are small, nocturnal, neo-tropical migrants that vocalize quietly and are rarely seen. Species-specific surveys are necessary to determine the distribution and abundance of this species.
Studies have shown a decline in cavity-nesting bird numbers following timber harvesting due to the loss of nesting cavities, but forest thinning creates open forests that Flammulated Owls prefer for foraging. Our objective is to determine how to balance these two habitat components to help conserve populations of the Flammulated Owl in the Sierra Nevada.
Geolocator Research on Sierra Nevada Swainson's Thrush (continuing)
The Swainson's Thrush has become alarmingly rare throughout the Sierra Nevada. They have become extirpated from many locations where they were formerly regularly breeding summer residents, such as Yosemite Valley. As elsewhere in the Sierra, they were once considered fairly common breeders at Lake Tahoe, reported as being common around Incline Village in June 1931; yet we know of very little current or recent evidence for breeding from the Sierra Nevada region, particularly south of Yuba Pass.
What caused these declines? What is the current breeding status and distribution in the Sierra Nevada? In 2009, TINS biologist Will Richardson found a small concentration of territorial Swainson's Thrushes in Ward Canyon, on the California side of the Tahoe basin. Several pairs of apparent breeders and two old nests were found, the first documented evidence of nesting in Tahoe in many decades.
The Tahoe Institute of Natural Science has partnered with the Point Reyes Bird Observatory to initiate and maintain a database on Swainson's Thrush in the Sierra Nevada. Initial efforts will be focused on compiling spatially-explicit data on breeding status for this species. Secondary efforts will be to monitor breeding populations and study them in greater depth (assess demographic parameters, habitat considerations, etc.), starting with the Ward Canyon population in 2010. Thanks to a generous grant from the Sierra Foothills Audubon Society, we will be deploying optical geolocators on breeding birds in 2014, to determine migratory pathways and wintering grounds for this enigmatic population.
GIS Mapping of Tricolored Blackbird Breeding Locations
Provided financial assistance for technicians to complete GIS mapping of breeding sites for Tricolored Blackbirds.
The Flammulated Owl Project, done in collaboration with the United States Forest Service, Beckworth Ranger District, is a study monitoring differential use of nest boxes in treated and untreated areas. The study areas are located all around Lake Davis and further north near Red Clover Valley.
We purchased geo locators for David Arsenault to mount on Flammulated Owls for his habitat use and migration study.
Migratory connectivity of Golden-crowned Sparrows
Sierra Foothills Audubon supported Point Blue Conservation Science (www.pointblue.org) in a study that used light-level geolocators to determine breeding locations and migratory routes from Golden-crowned Sparrows (Zonotrichia atricapilla). Of 15 geolocator tags that were deployed on Golden-crowned Sparrows in Placer County in the winter of 2013, 8 were recovered the following fall. Preliminary analysis of the data from these tags showed that these birds bred at interior sites in the Yukon, Northwest Territories, and British Columbia. On average, these birds traveled about 2,500 km to their breeding grounds and during spring their migration rate was about 115 km per day. Studies like this can increase our understanding of this understudied migratory species.
Rationale: Birds in general and raptors in particular represent a subset of wildlife that readily captures the attention and concern of the public. Besides the fact that several species of raptors are of conservation concern, these birds inspire widespread awe and respect among the general public.
The Central Valley of California supports an impressive abundance and diversity of these birds, especially in winter. A number of species are found in this area only in winter and even the species that are present year-round are augmented by a large winter influx of individuals from other parts of North America. Studies of the winter distribution of open country raptors (which comprise most species within this group) show that just two areas of the continent support the bulk of these populations in winter: the Coastal Plains of Texas and Louisiana and the Central Valley of California (Root 1988, Pandolfino 2006). Data from the annual Christmas Bird Count (CBC) show that, when comparing open country raptor abundance among nearly 2000 count circles located all across North America, five of the top six circles are found within the Central Valley of California (Pandolfino 2006). The Central Valley is host to significant numbers of more than a dozen different species of open country raptors in winter.
To this point, there have been almost no large scale studies of the winter distribution of raptors in the Central Valley. There is an almost complete lack of quantitative data on the habitat associations of these birds in the Central Valley during winter. We know that these birds are almost exclusively dependent on working farmland and rangeland in our area, but have no real data to understand the specific types of habitat each species uses.
The Project: Nineteen different roadside survey routes have been established throughout the Central Valley from Shasta County to Kings County (see map). In addition, routes have been established outside the Central Valley in the Carrizo Plains of San Luis Obispo County and the Fall River Mills area of Shasta County. Each of these routes is assigned to a well-qualified observer who will survey that route throughout the winter (attempting to survey each route at least once per month from December through February). For each observation the observer records the species, location and behavior of the bird. The nature of the habitat has been determined along each route at ½ mile intervals so that each raptor observation can be placed in a particular habitat type. Weather data and other information on the status of the habitat are also collected.
The first year of data collection (winter 2007-08) has been completed. These data will be collected for at least three consecutive winters. At that point a correlation will be established of the specific types of habitat which is most strongly associated each species.
The project is being conducted under the auspices of the Central Valley Bird Club (a California 501c3 organization).
Why is Sierra Foothills Audubon Society interested in this Project?: As discussed above, the Central Valley is arguably the most important area in North America for wintering raptors. It is also an area where substantial portions of critical raptor habitat are being lost to urban development and conversion to more intensive forms of agriculture. In order for conservation organizations like Sierra Foothills Audubon Society to influence public policy to preserve raptor habitat, we need good quantitative data on exactly which habitats are most important to the various species of wintering raptors. This project will provide those data and permit solid, science-based prioritization of areas most in need of preservation. Additionally, in terms of educating and motivating the public, hawks have special appeal. By highlighting the conservation needs of raptors, one can often rally support for preservation of habitat that also benefits a suite of other species that may not be quite as charismatic to the general public.
The costs for this project are modest and we are hopeful we can raise sufficient funding from local California organizations to support the project to its completion. We have received support from a couple of organizations and are in the process of soliciting donations from Audubon Chapters throughout the Central Valley. A grant from Sierra Foothills Audubon Society would greatly help our efforts. We are committed to completing the project and getting the results published in peer-reviewed journals. Data will also be made available to government agencies and planning authorities. Sierra Foothills Audubon will be regularly supplied with updates on progress of the project.
Zach Smith and Ed Pandolfino are the principal investigators for this project.
References:
Pandolfino, E.R. 2006 Christmas Bird Counts reveal winter bird status and trends in California’s Central Valley. Central Valley Bird Club Bulletin 9:21-36.
Root, T. 1988. Atlas of wintering North American birds. University of Chicago Press, Chicago, IL U.S.A.
Preliminary Budget for the Central Valley Raptor Project
Sierra Foothills Audubon Society made a significant gift in 2007 and 2009 toward a Black Rail research project that will promote the conservation of our newly discovered Sierra foothill population. The objectives of this research are to understand the factors that promote the success of this bird and to work with and engage private landowners in conservation on private land.
The planned result of this project will lead to a protocol so that this population can be properly assessed in California Environmental Quality Analysis (CEQA). It is important to note that the sites occupied by Black Rails are undergoing habitat destruction, habitat alteration and climate change from global warming.
The Black rail is a state threatened bird that is very secretive and sparsely distributed in the U.S. This species was discovered in the Sacramento valley in 1994 by Jerry Tecklin who is the field supervisor for this project. Dr. Steve Beissinger, the Black Rail Project Organizer, is the former chair of the Department of Environmental Sciences at UC Berkeley and a National Audubon Society board member.
Black Rails in the Sierra foothills primarily inhabit small, perennial, shallow wetlands. Most sites occur between 100-1200 feet in elevation and are densely vegetated. In addition, most are maintained by natural springs and/or leaks from canals carrying irrigation waters artificially created from the Gold Rush era to present.
Background proposal of work
Distribution and Metapopulation Dynamics of Black Rails in the Sierra Nevada Foothills.
Steven R. Beissinger and Jerry Tecklin,
Dept. of Environmental Science, Policy & Management, 151 Hilgard Hall, University of California, Berkeley, CA 94720-3110 beis@nature. berkeley.edu
We propose to continue and expand a study of the roles of land and water management on the population dynamics and distribution of Black Rails in the foothills Sierra Nevada Mountains (Yuba, Nevada and Butte Counties). This area is undergoing both rapid land conversion, and climate change from global warming. Black Rails are highly secretive and sparsely distributed in the U.S., and listed by the state of California as a threatened species. Black Rails had not been detected in the Sacramento Valley, except for one winter record, until 1994 when Jerry Tecklin and colleagues discovered a population in the foothills of the Sierra Nevada Mountains near Marysville. Surveys from 1996-1999 found rails at over 70 sites.
Black Rails in the Sierra foothills primarily inhabit small (0.5-10 ha), perennial, shallow (< 3 cm deep) wetlands. Most sites are at 200-700 m in elevation and were densely vegetated. Many are maintained by natural springs and/or by leaks from canals carrying irrigation water artificially created from the Gold Rush era to present. Dry annual grasslands, partially wooded grasslands, or oak or pine woodlands surround these wetlands, which occurred primarily as isolated habitat patches occasionally connected by slow flowing streams or water courses. Thus, the rails are distributed in a metapopulation (a population of populations), with hundreds of clearly defined local patches of suitable wetland habitats surrounded by an inhospitable matrix of other habitats.
During the past three years we have been systematically surveying 130 sites to determine the rate that occupied wetlands become unoccupied from one year to the next (“local extinction”) and the rate that unoccupied wetlands become occupied (“colonization”). During the first year we visited potential wetland sites up to 5 times to determine presence or absence of rails by broadcasting rail calls and measured a variety of coarse habitat characteristics at each site. Most marshes registered a response on the first visit, with additional detections during the second visit. Three visits were sufficient to yield a >97% probability of detection. Rails were present in 66% of the marshes. Rails were more likely to inhabit large marshes with permanent water sources that were not grazed. Our work has documented that rates of extinction and colonization vary annually, marshes used by rails can be both readily created and destroyed, and private land owners can be engaged in conservation activities
Objectives of our Research
The ultimate objectives of our research are to understand the factors promoting persistence of a threatened, poorly known and secretive water bird, the Black Rail, and to work with and engage private landowners in conservation on private lands. Our first phase of work (2001-2005) is based on conducting large-scale surveys to determine the occurrence of rails, and to develop models of habitat use and extinction-colonization dynamics for conservation. A second phase of work will begin in 2006 (-2008) that will include direct studies of rail biology using telemetry and other methods.
The specific objectives of this project are to: (1) Resurvey all 130 sites visited previously to determine the presence or absence of Black Rails; (2) Develop a statistical model to predict the occurrence of black rails throughout the foothills based primarily on remotely sensed data; (3) Conduct surveys at additional sites to test the model and determine the extent sites supporting Black Rails throughout the Sierra foothills; (4) Estimate rates of extinction and colonization of sites using consecutive years of presence/absence data: (5) Examine how rates of extinction and colonization are related to wetland size, isolation, water management, grazing, and land use activities; and (6) Use this information to inform and work with private land owners through extension activities, and state and federal agencies.
Methods
High spatial resolution (small pixel size), multispectral (including more information than just visible color) satellite-acquired imagery has been used successfully in mapping wetland ecosystems in estuarine environment. The near infrared data provided in these products is particularly well-suited to capture variations in vegetation. We propose to use multispectral imagery to map small wetlands in a grassland habitat. Field reconnaissance and initial investigation with digital color aerial photography suggest that the resolution provided by the QuickBird satellite will be sufficient to identify wetlands used by rails in a semi-automated manner. This satellite provides both multispectal imagery (the imagery has blue, green, red and near infrared bands at 2.44m spatial resolution), and panchromatic (black and white imagery at 0.61m spatial resolution).
We are requesting support for “pan-sharpened” (where the two resolutions are combined) QuickBird multispectral imagery taken at the end of the dry season for the study area (approximately 200 km 2). We will use the 130 wetlands we have been studying to develop a semi-automated algorithm for locating the sites based on the largest spectral difference between the wet spring vegetation and the surrounding dry grasslands. We measure wetland size, isolation; and characteristics from the images. We will also evaluate the characteristics of the landscape surrounding each marsh at various scales (100-1000 m radii) to estimate the proportion of land cover, distance to road, and fragmentation. Using logistic regression, we will determine which characteristics are most likely to predict the presence of rails. To test the model, we will use the imagery to identify 75 additional wetlands where we have yet to survey, measure the appropriate variables, and then use the model to predict the likelihood of rails occurring in each site. Finally, we will conduct rail surveys to test the model.
From June-August 2005 we will survey 75 new sites (identified from remote sensed images) and resurvey all 130 sites surveyed previously by contacting each landowner personally and getting permission to enter the site. We will conduct playback surveys at each site up to three times to determine presence or absence of rails. Sites will be visited from 30 minutes before sunrise until 210 minutes after sunrise and from 180 minutes before sunset until 30 minutes after sunset. The tape includes 4 min. of calls and silence intervals interspersed, followed by a final listening period of 2 min. timed by a wristwatch. If a rail is not detected, we walk another 50 m into the prime habitat and repeat the playback protocol. Surveys end at a site when unambiguous rail responses are detected and confirmed, or the entire marsh is surveyed. At each site we also collect information about habitat conditions. Area will be measured by GPS. Habitat conditions fall in three themes: (1) grazing; (2) water sources; and (3) vegetation types.
The final products will be: (1) a statistical model to estimate the chance that a marsh will support black rails in the Sierra Nevada foothills that can be used by agencies in assessing impacts of future development; (2) Determining and mapping the extent of wetland sites that support Black Rails throughout the Sierra Nevada foothills; (3) estimates for rates of local extinction and colonization of wetlands in relation to land ownership (public vs. private), wetland size, isolation, water management, grazing, and land use: and (4) Use this information to inform and educate private land owners, citizens, and state and federal agencies.
Sierra Foothills Audubon Society has recently financially supported a proposal by Robert J. Meese, Ph.D. and William J. Hamilton, III, Ph.D. Department of Environmental Science & Policy University of California at Davis to monitor Tricolored Blackbirds in the Central Valley.
The Tricolored Blackbirds is a California endemic species that diverged ca. 3.5 million years ago from its nearest relative and commonest bird in North America, the red-winged blackbird. The Tricolored Blackbird has two major populations: the Central Valley population, including the surrounding foothills to 3,000′, and the Southern California population, from Riverside County to northern Baja California.
Due to the near-elimination of its native breeding habitat (fresh water emergent marsh) and surrounding foraging habitats, the tricolor has declined steadily in abundance throughout its range. In response to this steep population decline, a petition has been filed to list the species for protection under the Endangered Species Act (Center for Biological Diversity, 2004).
Field work in support of Tricolored Blackbird conservation may be roughly divided into two phases: 1) Detection, and 2) Monitoring. These are followed by Phase 3 – Analysis.
Phase 2, from the first of May until the end of July or middle of August, consists of detecting colonies forming in the northern portions of the Central Valley and following and documenting the fates of all large colonies, including entering colonies to estimate reproductive success, and quantifying the results of breeding efforts from the largest silage colonies.
The Phase 2 proposal supported by SFAS will leverage the funding to be provided by the U.S. Fish & Wildlife Service and cover the month of May, and allow the completion of the field work in the southern San Joaquin Valley and detect, document, and estimate the sizes of the nesting colonies in the Sacramento Valley.
Background
The Tricolored Blackbird, Agelaius tricolor, is a California endemic species that diverged ca. 3.5 million years ago from its nearest relative and commonest bird in North America, the red-winged blackbird (Agelaius phoeniceus; Yasukawa and Searcy, 1995). The Tricolored Blackbird (hereafter, tricolor) has two major populations: the Central Valley population, including the surrounding foothills to 3,000′, and the Southern California population, from Riverside County to northern Baja California (Beedy and Hamilton, 1999). The extent of mixing between these subpopulations is unknown, but the Riverside County population is known to be resident (Tom Paulek, San Yacinto State Wildlife Area Manager, pers. comm.).
Due to the near-elimination of its native breeding habitat (fresh water emergent marsh) and surrounding foraging habitats, the tricolor has declined steadily in abundance throughout its range (Beedy, Sanders, and Bloom, 1991; Hamilton 2003). The first formal population assessment was conducted in the 1930’s (Neff, 1937), and population estimates made in the last decade have demonstrated a decline of nearly 60% in the interval from 1930 to 2000. Recent estimates were derived from data gathered through all-out efforts to locate colonies on a single weekend in late April in three years: 1994, 1997, and 2000 (DeHaven, 2000, Hamilton, 2004). These efforts continued with another all-out effort in 2005. In response to this steep population decline, a petition has been filed to list the species for protection under the Endangered Species Act (Center for Biological Diversity, 2004).
The current status of the rapidly declining Southern California population of tricolors is imprecisely known, as previous surveys have not included dates encompassing the southern California breeding season. However, the known large (>20,000 birds) colonies frequenting eastern Riverside County have not been reported in recent (since 2000) years, and searches for San Diego County colonies have found fewer colonies in recent (2000-2004) than in previous years (Phil Unitt, pers. comm.), so what data exist suggest a decline to near-extinction in the Southern California population over the past several decades.
Federal and State agencies, NGOs (e.g., Audubon California), and private landowners, with the assistance of University of California and other researchers, have responded to the decline in abundance of tricolors in several ways, primary among them the support of small, dedicated teams of field researchers employed to detect settlements and to assist in the subsequent protection of large nesting colonies in silage. Several of these groups and individuals have been come together to form the “Tricolored Blackbird Working Group” (TCBBWG). The TCBBWG holds bimonthly meetings in Sacramento with the goal of working cooperatively to better understand the reasons for and to stem the decline in abundance of the tricolor and to coordinate efforts to reverse the decline and to ensure the long- term persistence of the species. Members of the TCBBWG have provided partial financial support for the intensive studies of the species that began over a decade ago, with the work of William J. Hamilton, III and his collaborators and students (Hamilton, 1997).
These studies have documented, among numerous other aspects of tricolor biology, the rapid utilization, over the past decade, of silage fields for nesting substrate in the San Joaquin Valley, concomitant with the rapid expansion of the dairy industry in this region. These silage fields, primarily triticale (a vigorous and productive wheat x rye hybrid grain grown to feed dairy cattle) supported over 50% of all nests observed in 2005. Thus, a primary management activity has become the early detection, by tricolor field researchers, of birds settling in to triticale fields on or adjacent to dairies followed immediately by the reporting of these colonies to U.S. Fish & Wildlife Service staff who then contact the landowner and attempt to buy out the triticale. Due to this recent dependence upon breeding in silage, any strategy to conserve this species must focus on the increasing silage dependence and protect silage colonies in the short term while providing alternative, more secure nesting substrates in the region for the longer-term.
Required Field Work
The tricolor has been studied for over a decade by a small group of dedicated researchers, and many recommendations for tricolor conservation and management have developed in response to these studies (Hamilton, 1997; DeHaven, 2000; Hamilton and Meese, 2005). We propose to continue the required field studies to support tricolored blackbird conservation efforts in the Central Valley of California. It is stressed that similar if not greater efforts need to be made in Southern California, but logistical constraints prevent one individual from working in both portions of the species’ range in a single field season.
Field work in support of tricolor conservation may be roughly divided into two phases: 1) Detection, and 2) Monitoring. These are followed by Phase 3 – Analysis.
In Phase 1, which begins on the first of March and lasts until the end of April, field researchers survey previous large tricolor breeding colony sites and search for new colonies as they begin to form. In the earliest part of this period, essentially all efforts at colony detection are directed toward the silage fields of the San Joaquin Valley, as these sites recently have supported a disproportionate number of breeding birds. The locations of all colonies are documented with GPS coordinates, the physical dimensions of each colony are measured directly or via GPS, and estimates of the numbers of birds present on each visit are made. A proposal for funding has been submitted to the U.S. Fish & Wildlife Service, Sacramento to support the Phase 1 field work.
Phase 2, from the first of May until the end of July or middle of August, consists of detecting colonies forming in the northern portions of the Central Valley and following and documenting the fates of all large colonies, including entering colonies to estimate reproductive success, and quantifying the results of breeding efforts from the largest silage colonies. In Phase 2, as time permits, intensive field observations are made of foraging birds in order to document choices of destinations, foraged substrates, foods selected, and time of breeding cycle. Then, following fledging, the numbers of nests in the largest colonies are estimated by plot or transect sampling to provide a quantitative estimate of breeding colony population sizes, and serves as a check on previous visual estimates. This proposal would leverage the funding to be provided by the U.S. Fish & Wildlife Service and cover the month of May, and allow us to complete the field work in the southern San Joaquin Valley and detect, document, and estimate the sizes of the nesting colonies in the Sacramento Valley.
Phase 3 begins as soon as field work ends, and consists of office work: data input, analysis, and synthesis, report writing, map production, and manuscript preparation. These activities take the remainder of the year (i.e. August through December). Additional proposals will be submitted to the California Department of Fish & Game and other funding agencies to support the late-season field work and subsequent office work.
The early detection of breeding colonies is essential, as early detection allows: 1) an opportunity to conserve those colonies established in silage fields in the southern San Joaquin Valley, 2) an estimate of colony chronology (i.e. an estimate of when the nests were built, eggs were laid, etc.), and 3) a chance to make specific management recommendations that may help to ensure colony productivity. A knowledge of breeding chronology is essential to enable field staff to enter colonies at the appropriate times to estimate reproductive success and to correlate foraging behavior with stage in the breeding cycle, as major shifts in foraging occur as soon as the eggs hatch. An annual effort to follow and document the fates of all of the larger colonies is essential to estimate reproductive success and to monitor the population. And an opportunity to make specific management recommendations may help to increase the chances for successful reproduction as predators may be detected and deterred. Both black-crowned night herons (Nycticorax nycticorax) and coyotes (Canis latrans) may cause severe reductions in productivity, and early detection of coyotes, especially, may enable managers to take steps to reduce mortality due to coyote predation.
A more thorough understanding of tricolor foraging is required to better estimate the amount and types of foraging habitats needed to support a breeding colony. Historically, very little has been written about the foraging habits of tricolors and many novel insights were gained from the intensive observations made in 2005.
Significance to Species Management and Conservation
Major declines in tricolored blackbird abundance have resulted in the implementation of a few initial habitat management actions including mitigation, active refuge management, and fencing of traditional nesting sites. The need for active management is due both to the steep decline in abundance as well as the recent trend toward silage-dependent nesting. The precipitous decline in the southern California population – a population that may be genetically distinct from the Central Valley population, urgently requires its own conservation actions. It is essential to have experienced observers in the field to detect initial settlements and to communicate with local U.S. Fish & Wildlife Service staff in those cases where settlements occur in silage on private property. Dedicated field researchers are necessary to monitor the fates of the breeding colonies through the breeding season, to estimate reproductive success, and to document the relationships between breeding and foraging. The essential outputs from these activities will be specific management recommendations that will most effectively and efficiently support the long-term persistence of the species.
Literature Cited
Beedy, E.C. and W.J. Hamilton III. 1997. Tricolored blackbird status update and management guidelines. (Jones & Stokes Associates, Inc. 97-099) Sacramento, California. Prepared for U.S. Fish and Wildlife Service, Portland, Oregon and California Department of Fish and Game, Sacramento, California.
Beedy, E. C. and W. J. Hamilton III. 1999. Tricolored blackbird (Agelaius tricolor). In A. Poole and F. Gill (eds.), The Birds of North America, No. 423. Philadelphia, PA: Academy of Natural Sciences and Washington, DC: American Ornithologists Union.
Beedy, E.C., S.D. Sanders, and D. Bloom. 1991. Breeding status, distribution, and habitat associations of the tricolored blackbird (Agelaius tricolor) 1850-1989. Prepared by Jones and Stokes and Associates for U.S. Fish and Wildlife Service, Sacramento, California.
Center for Biological Diversity. 2004. Petition to list Tricolored Blackbird under the State and Federal Endangered Species Acts and Request for Emergency Action to Protect the Species.
DeHaven, R.W.. 2000. Breeding tricolored blackbirds in the Central Valley, California: A quarter century perspective. Prepared for the U.S. Fish and Wildlife Service, Sacramento, California.
Hamilton, W.J. III. 2000. Tricolored Blackbird status report 2000. Report prepared for the U.S. Fish and Wildlife Service, Portland, Oregon.
Hamilton, W.J. III. 2004. Management implications of the 2004 Central Valley Tricolored Blackbird Survey. Central Valley Bird Club Bulletin 7: 23 – 31.
Hamilton, W.J. III. and R.J. Meese, 2005 (in prep.). Habitat and Population Characteristics of Tricolored Blackbird Colonies in California. Report to be submitted to the California Department of Fish & Game.
Neff, J.A. 1937. Nesting distribution of the tri-colored red-wing in Central California. Condor 39:61-81.
Yasukawa, K. and W. A. Searcy. 1995. Red-winged blackbird (Agelaius phoeniceus). In A. Poole and F. Gill (eds.), The Birds of North America, No. 184. Philadelphia, PA: Academy of Natural Sciences and Washington, DC: American Ornithologists Union.