The International Rusty Blackbird Technical Group: The First Year in Review
In March 2005, the International Rusty Blackbird Technical Group (IRBTG) was formed in response to the severe declines that have been document in the species. The causes of the decline remain unclear and the species has not received sufficient attention to understand the underlying problems and to develop management solutions. To begin to address the lack of knowledge and awareness, the IRBTG developed a network of people focused on research and/or elevating awareness in the public and relevant organizations and agencies.
The IRBTG was established to develop an integrated and coherent approach to research and conservation of this species. Through increased communication and collaboration, the key issues can be defined and human and monetary resources focused in a strategic way. In the first year, the IRBTG has increased communications between RUBL researchers through regular meetings, a list-serve, and a website. More important, the IRBTG developed an over-arching research strategy, which serves as a conceptual tool for organizing and prioritizing research activities.
Starting with an almost clean slate, the IRBTG has make substantial, tangible headway in both research and educational outreach on the decline of the Rusty Blackbird. Here we outline the specific accomplishments in breeding and wintering ground research, isotope analysis, outreach both among professionals and the public at-large, and resource development for future work.
Breeding Season Research
The current distribution and areas of concentration of breeding
Rusty Blackbirds in the boreal zone remains poorly documented.
The Alaska Natural Heritage Program in cooperation with
the Alaska Department of Fish and Game compiled information
on the distribution of Rusty Blackbirds in Alaska. Data
sources included the North American Breeding Bird Survey,
Alaska Landbird Monitoring Survey, Checklist program on
DoD lands, and incidental observation by biologists across
the state. These data suggest that wetlands and riparian
areas along the Yukon and Kuskokwim rivers and their tributaries,
particularly in western Alaska, supported the highest densities
of breeding birds in the state. These data will be analyzed
to identify important habitats for breeding Rusty Blackbirds
in Alaska.
Meanwhile, biologists from the Canadian Wildlife Service will be surveying Canadian sites where Rusty Blackbirds were reported to be common in past decades. This includes areas surveyed for the environmental impact report for a proposed gas pipeline in the MacKenzie region of the Northwest Territories. In the Yukon Territory, Rusty Blackbirds have been included in the roadside wildfowl surveys with good success: Rusties were foun at a quarter to a third of the 257 focal wetlands.
Collection of blood and feathers for isotope, genetic, and mercury analysis (see below) was initiated. Steve Matsouka, working with other biologist from the U.S. Fish and Wildlife Service and Alaska Bird Observatory, tested capture techniques and sampled feathers and blood from 15 Rusty Blackbirds in Bethel, Alaska, in August 2005. Birds were captured using a combination of mist nets and baited funnel traps constructed from hardware cloth. Traps were effective in capturing Rusty Blackbirds considering the small number of birds in the area. Pam Sinclair and her coworkers at the CWS collected feather samples from over 100 blackbirds during spring and fall migration in Southern Yukon.
Perhaps the most important short-term goal for breeding season research is the establishment of study areas for more in-depth ecological research. Breeding studies have been proposed for 2006 in multiple locations in Alaska including Innoko National Wildlife Refuge along the Yukon River (USFWS), the Chugach National Forest's Copper River Delta (USFS), and DoD installations and state game refuges in Anchorage and Fairbanks (Alaska Bird Observatory, DoD, Fish and Game, USFWS). The CWS identified a potential study site near Whitehorse, Yukon Territory. Thus it is likely that at least one significant breeding study will be initiated on the species in 2006 in Alaska. Surveys for extant breeding pairs in northern U.S. are being conducted by William Glanz and Thomas Hodgman (Maine).
Fig. 1. Distribution and abundance of breeding Rusty Blackbirds in Alaska based on data from the BBS, Alaska Landbird Monitoring Survey, and DoD checklists. Map symbols denote abundance as follows: yellow = absent, small green = rare to uncommon, large green = common to abundant.
Winter Research
Research on the wintering grounds has begun in earnest with
studies focused on the Lower Mississippi Valley (LMV) alluvial
plain (e.g., Theodore Roosevelt National Wildlife Refuge
complex and the Cache and White River NWR). The two major
themes of the work are increasing our understanding of the
behavioral ecology of the species and use of habitat in
the forest/farm mosaic. Claudia Mettke-Hofmann, collaborating
with Gerhard Hofmann, Russell Greenberg, and Paul Hamel,
has completed a study of novelty responses in Rusty Blackbirds
as part of a comparative study of North American blackbirds.
The Rusty Blackbird is significantly more neophobic than
the other common blackbirds of the area, an attribute that
may contribute to its decline in the face of anthropogenic
change in habitat.
Jason Luscier is developing survey techniques that will provide statistically robust data on the distribution of species with respect to habitat and the abundance of other potentially competing blackbirds. In a pilot study he surveyed 84 sites at least four times and will be able to analyze the data for seasonal changes in distribution and habitat use. The technique is relatively easy to implement and, therefore, can be used by large numbers of observers to conduct regional atlas projects.
Pilot work on radio-tracking individuals has just been initiated by Claudia and Gerhard Hofmann and Paul Hamel, with some success at tracking individuals. This should prove to be an invaluable tool in determining space use. In addition, over 50 birds have been captured, measured, color banded, and sampled for blood and feathers at the LMV site. One interesting finding is that flocks at different localities have different sex/age class composition, a phenomenon that if found to be general could provide insights into how Rusty Blackbirds assess habitat quality.
Isotope Analysis
The goal of the isotope analysis, spearheaded by Keith Hobson, is to establish the connectivity of breeding and wintering populations. Through analysis of deuterium ratios in museum skins and free-ranging birds, the latitude of breeding origin can be estimated both historically and under present-day conditions. A comparison of historical and current patterns may provide insights into where declines are occurring on the breeding grounds. Over 190 samples have been obtained from 11 museum collections and more are still coming. In addition, as the above accounts state, samples of 15 and over 50 birds have been obtained from Alaska and the LMV, respectively. We currently have field teams heading to sites in the Carolinas to sample the Atlantic coastal plain winter population (where declines have been particularly severe). Preliminary analysis of museum samples has provided results that verify that the technique will provide good results.
Mercury and Calcium Analysis
In the acidic wetlands of the boreal forest, the impact of acid rain and mercury contamination may be exacerbated. In addition, mercury contamination may be an issue in regions of the southeast where the Rusty Blackbird winters. David Evers has initiated a project sampling both Rusty Blackbirds and other species that share its habitat, to look for evidence of high mercury levels and depletion of calcium (an effect of acid rain). He has run analysis on blood and tissue samples from Alaska, and will be analyzing feathers from historical samples in museum collections. He is particularly interested in obtaining new samples from the scattered populations in northern New England, as well as the coastal plain and piedmont of the Carolinas. A field team is headed to collected samples in the Carolinas later this winter, and material is being taken from birds in the LMV as well.
Outreach
Information about the decline in Rusty Blackbirds is being disseminated to ornithological communities as well as agencies and organizations involved in bird conservation. Short communications have been disseminated on regional and national list-serves (e.g. E-birds) and to the bulletin of the Ornithological Societies of North America. Short articles or letters have been or will be published as well (e.g. Audubon Naturalist Society Newsletter, and the Cornell Lab of Ornithology "Winging It").
A great opportunity for raising awareness comes this spring, when the theme of International Migratory Bird Day will be birds of the boreal forest. The Rusty Blackbird has made it on the t-shirt and poster and information about the species will be included in the organizer information kit as well. It is fair to say that the awareness of the problem has increased greatly in the past year and, working with Partners in Flight and the Boreal Bird Initiative, we will be able to expand upon our efforts greatly.
Financial Strength
DOD Legacy will provide $20 K to support research on the wintering grounds. Support ($8 K) has been obtained for winter field work from the Migratory Bird Division of the Southeast Region of the FWS thanks to the work of Dean Demarest and Claudia Mettke-Hofmann. It appears likely that an additional $35 K will be provided from the National Wildlife Refuge cost-share program. Additional direct or in-kind support has been provided by the USFS, Smithsonian Bird Center, USFWS, Alaska Bird Observatory, Biodiversity Research Institute, Max-Planck-Institute for Ornithology, Arthur-von-Gwinner Foundation, and the USDA Forest Service. A proposal to list the species as one of management concern for the USFWS is in the works and if this occurs, then the potential for support for research and management of this species will increase in the future.
