Migratory Bird Program
Conserving the Nature of America

NONGAME BIRDS OF MANAGEMENT CONCERN - THE 1995 LIST

Executive Summary Literature Cited
Introduction Discussion
The Evaluation Process Management Recommendations
Selection Criteria Acknowledgments


THE 1995 LIST

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  • Table 1
  • Table 2
  • Table 3
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    Executive Summary

    This document revises the 1987 list of migratory nongame birds that are thought to be of management concern. These species are of concern because of (1) documented or apparent population declines, (2) small or restricted populations, or (3) dependence on restricted or vulnerable habitats. The document partially fulfills the requirements of the Fish and Wildlife Conservation Act of 1980, as amended. The 1988 amendments to the Act direct the Secretary of the Interior to "identify species, subspecies, and populations of all migratory nongame birds that, without additional conservation action, are likely to become candidates for listing under the Endangered Species Act of 1973."

    A five-step process was used to identify species of concern: (1) a modified group decision-making exercise (Delphi), (2) a review of Breeding Bird Survey data, (3) a review of Audubon Christmas Bird Count data, (4) a review of Partners in Flight prioritized regional lists of neotropical migrant landbirds, and (5) a review of the U.S. Fish and Wildlife Service's (USFWS) "candidate" species list. To qualify for national listing, a species had to meet at least one of the following selection criteria: (1) A Delphi score of Moderate or High concern by more than 50% of all respondents, (2) a long-term (1966-1993) population decline documented by the Breeding Bird Survey that equals or exceeds 2.5%/year, (3) a long-term (1959-1988) population decline documented by the Audubon Christmas Bird Count that equals or exceeds 2.5%/year, (4) a composite Partners in Flight rank score of at least 24 in (a) 2 or more USFWS regions or (b) the USFWS region that contains at least 50% of the U.S. breeding range or population, or (5) a Category 1 or Category 2 "candidate" species in a geographical area covering at least 10% of the U.S. breeding range.

    One hundred and twenty-two (122) species were determined to be of management concern at a National level. Of 30 species on the 1987 list, 24 are retained and 6 are deleted (because of Endangered or Threatened species listing or lack of concern). Ninety-eight species are added to the list. Some, but by no means all, of the increase in the number of listed species can be attributed to a change in the listing criteria, with the 1995 criteria being much more comprehensive. Thirty-seven percent of the listed species are also high priority on one or more Partners in Flight regional lists and 34% are listed as "candidates" in one or more regions.

    This list is intended to stimulate a coordinated effort by Federal, State, and private agencies to develop and implement comprehensive and integrated approaches for the management of selected species of nongame birds deemed to be in the most need of additional conservation actions. Since species are the major building blocks of the communities of which they are a part, we also hope that the list will promote greater study and protection of the habitats and ecological communities upon which these species depend.

    Introduction

    A primary goal of the U.S. Fish and Wildlife Service (USFWS) is to conserve avian diversity in North America (USFWS 1990); this includes reducing the likelihood of having to propose any migratory bird species for Federal listing as Endangered or Threatened.

    The purpose of this document is to identify those species of migratory nongame birds that are considered to be of concern in the United States because of (1) documented or apparent population declines, (2) small or restricted populations, or (3) dependence on restricted or vulnerable habitats. It supercedes a similar list prepared in 1987 (USFWS 1987). This document partially fulfills the requirements of the Fish and Wildlife Conservation Act of 1980, as amended (P.L. 100-653, Title VIII), to "identify species, subspecies, and populations of all migratory nongame birds that, without additional conservation actions, are likely to become candidates for listing under the Endangered Species Act of 1973." This list should not be confused with either the "animal candidate review" prepared under authority of the Endangered Species Act and updated biannually (USFWS 1994) or the series of prioritized regional lists of neotropical migrant landbirds prepared under the auspices of Partners in Flight, the Neotropical Migratory Bird Conservation program (e.g., Carter and Barker 1993, Hunter et al. 1993, Smith et al. 1993, and Thompson et al. 1993). Each of these lists was developed for different purposes using different criteria or procedures. However, to the extent possible, the "candidate" and Partners in Flight lists have been integrated into the criteria used to identify species of "management concern."

    The underlying philosophy behind this report is that "an ounce of prevention is worth a pound of cure." We fervently believe that a well-designed program that addresses resource-management issues at an early stage, thereby preventing species from having to be listed as Threatened or Endangered, will be more cost-effective than the full-blown recovery effort required once a species is Federally listed. We hope that "Migratory Nongame Birds of Management Concern in the United States: the 1995 List" will, like its predecessor, stimulate a coordinated effort by Federal, State, and private agencies to develop and implement comprehensive and integrated approaches for the management of selected species of nongame birds deemed to be in the most need of additional conservation actions. Since species are the major building blocks of the communities and ecosystems of which they are a part, we also hope that this list will promote greater study and protection of the habitats and ecological communities upon which these species depend.

    The Evaluation Process

    Because of the variety of factors affecting bird population status, and our limited knowledge of bird population trends (e.g., only about one-half of the species breeding in the United States are adequately monitored), a five-step process was used to identify species of concern. The five steps include:

    1. a modified group decision-making exercise (Delphi; see Caughlin and Armour 1992)),
    2. a review of Breeding Survey data,
    3. a review of Audubon Christmas Bird Count data,
    4. a review of Partners in Flight prioritized regional lists, and
    5. a review of the "candidate" list.

    This effort focuses on those species of birds that are:

    1. protected by the Migratory Bird Treaty Act (USFWS 1985);
    2. regularly found in the continental U.S., Hawaiian Islands, Puerto Rico, or the U.S. Virgin Islands;
    3. regular breeders or winter residents in one of the above geographical areas;
    4. not currently hunted for sport under provisions established by the Migratory Bird Treaty Act; and
    5. not Federally listed as Endangered or Threatened throughout their U.S. range.

    Delphi. This is an attempt to harvest the collective wisdom of a selected subset of "experts" on bird distribution and abundance. Delphi is an appropriate data-gathering tool when definitive or quantitative information on a subject is unavailable, a situation that pertains to the status of many bird populations. The Delphi exercise was conducted in three phases:

    (a)Phase I. This exercise was initiated by compiling a list of approximately 545 species of migratory nongame birds known to breed in the continental United States. In March 1992, this list--plus supplementary information--was provided to 10 USFWS biologists with extensive knowledge of bird distribution and abundance. These biologists were asked to review the list and to rank each species according to their perceived degree of concern for the welfare of the species. The results of this preliminary evaluation were compiled in September 1992 (USFWS 1992).

    (b)Phase II. A tabular summary of the results of Phase 1--together with supporting information on national trends from the Breeding Bird Survey, a synopsis of 12 National Audubon Society "Blue Lists" (1972-1982 and 1986; Tate 1986), and the status of "candidates" for Endangered or Threatened species listing--was provided to 52 Regional Editors of American Birds (a journal of the National Audubon Society), and to the USFWS's 7 Regional Migratory Nongame Bird Coordinators (RMNBCs) in July 1993. Collectively, these individuals possess a wealth of knowledge on the distribution and abundance of North American birds. Participants were given four choices for indicating their degree of concern for the welfare of each species: None, Low, Moderate, High. They were instructed to base their evaluations on personal knowledge, personal communications with others, information gleaned from the literature, information on short- and long-term population trends when available, and other information provided. For species that they rated Moderate or High concern, participants were asked to indicate the reason(s) for their concern. Their choices were (a) negative Breeding Bird Survey trend, (b) apparent population decline or range retraction (a subjective evaluation that may or may not be supported by Breeding Bird Survey trends) , (c) small population and/or restricted range, (d) restricted or vulnerable habitat, or (e) specific threats (participants were asked to specify habitat loss, human disturbance, contaminants--including pesticides, or other). Most of the RMNBCs consulted with other experts in their regions (i.e., State nongame programs, university researchers, etc.), and the results of these consultations are reflected in their evaluation forms. Completed evaluation forms were received from 40 individuals (Appendix A), a response rate of 67%.

    (c)Phase III. In response to a concern expressed by the RMNBCs that certain outlying geographical areas (i.e., Alaska, Hawaii, and Puerto Rico/U.S. Virgin Islands) had not been adequately surveyed by the Delphi exercise, special evaluation forms were developed for each of these areas. Except for the species listed, the forms were identical to those used in Phase II. The forms were sent to selected groups of area "experts" identified by the RMNBCs in October 1994. Twenty completed evaluation forms were received from 21 individuals (Appendix A). The distribution of Delphi scores from Phases II and III was tabulated, and median values calculated, for each species by USFWS Regions (Appendix) and other geographical areas.

    Other Data Sources.Procedures followed in reviewing the Breeding Bird Survey, the Audubon Christmas Bird Count, the Partners in Flight prioritized regional lists, and the "candidate" list are discussed in the next section.

    Selection Criteria

    Five selection criteria were used to determine whether a species qualified for national listing. A species could qualify by meeting any one of the following criteria:

    (1) Delphi. Species assigned a Delphi score of Moderate or High concern by more than 50% of all (minimum of 5) respondents. Of approximately 600 species evaluated, 72 met this criterion for listing; 63 were identified in the survey of American Birds regional editors and RMNBCs, and 9 were added in the followup survey of Alaska, Hawaii, and Puerto Rico/U.S. Virgin Islands "experts."

    (2) Breeding Bird Survey(BBS). Species has an apparent long-term (1966-1993) continental population decline documented by the BBS that equals or exceeds 2.5%/year (P < 0.05). This is an effort to highlight species suffering chronic population declines that were not identified in the Delphi exercise. An estimated trend of -2.5%/year amounts to a cumulative decline of about 50% over a span of 27 years. A decline of this magnitude is considered to be biologically significant, even for species that are widely distributed and relatively abundant. A review of the approximately 424 eligible species in the BBS database revealed 81 species with significant long-term (1966-1993) population declines at a continental level [NOTE: To avoid biases due to small sample sizes, all species with a degree of freedom (i.e., total number of routes minus total number of states or provinces) of less than 50 were excluded from consideration. Also, two species that otherwise qualified for listing under this criterion (white-throated swift and boreal chickadee) were dropped from consideration because of concerns about the reliability of the BBS trend estimates (B. Peterjohn, pers. comm.)]. The logical next step would be to identify that subset of species with the most extreme population declines. However, when sampling variation is a substantial proportion of the total variation in a collection of estimates (as is the case with BBS data; Link et al. 1994), "the species identified by their extreme trend estimates are likely to be a poor representation of the species actually undergoing the greatest rates of population change" (W. A. Link and J. R. Sauer, unpublished manuscript), even when the assessment is limited to those species with statistically significant trends. To avoid the potential biases of sampling variation, we used constrained empirical Bayes estimates of population trend (W. A. Link and J. R. Sauer, unpublished manuscript) for the 81 species for which there was evidence of significant declines. Twenty-one species met this criterion for listing (including 12 that already qualified on the basis of Delphi scores).

    (3) Aubudon Christmas Bird Count(ACBC). Species has an apparent long-term (1959-1988) continental population decline documented by the ACBC that equals or exceeds 2.5%/year (P < 0.01). As with the BBS, this is an effort to highlight species suffering chronic population declines that were not identified in the Delphi exercise. A review of the approximately 369 species in the ACBC database revealed 49 species with significant long-term (1958-1988) continental population declines. [NOTE: To avoid potential biases in the database, only species with sample sizes equal to or greater than 100 were considered. Also, four species that otherwise qualified for listing under this criterion (semipalmated sandpiper, black-legged kittiwake, "Baltimore" oriole, and rusty blackbird) were dropped from consideration because of concerns about the reliability of the ACBC trend estimates]. Five species met this criterion for listing (including 4 that already qualified on the basis on Delphi scores or BBS trends).

    (4) Partners in Flight (PIF). Species has a composite PIF rank score of at least 24 in (a) 2 or more USFWS regions or (b) the USFWS region that contains at least 50% of the U.S. breeding range or population. Prioritized regional lists were reviewed for USFWS Regions 1-6 (unpubl. data provided by J. Bradley and M. F. Carter in November 1993), USFWS Region 7 (Alaska) (unpubl. data provided by B. Andres in October 1994), and Puerto Rico/U.S. Virgin Islands (unpubl. data provided by W. C. Hunter in November 1994). Each of these lists was prepared using a standardized format and ranking criteria (e.g., Carter and Barker 1993). PIF rank scores ranged from 7-34, with higher scores indicating greater degrees of concern. Within each region, about 10% of the species had scores of 24 or more. Thus, this criterion is designed to incorporate only those species of neotropical migrant landbirds for which the greatest degree of concern has been expressed by PIF (i.e., the highest ranking 10%). Of 254 species reviewed (see Research Working Group 1992), 68 had a score of 24 or more in at least one region, and 44 met this criterion for listing (including 20 that already qualified on the basis of Delphi scores, BBS trends, or ACBC trends).

    (5) Candidate List. Species listed as a Category 1 or Category 2 candidate in a geographical area covering at least 10% of the U.S. breeding range. Of 92 taxa (species, subspecies, and populations) of birds listed as Category 1 or Category 2 candidates (USFWS 1994), 67 taxa (61 species) were eligible for consideration (i.e., they fell within the focus of this exercise) and 40 species met this criterion for listing (including 24 that already qualified on the basis of Delphi scores, BBS trends, or PIF scores).

    Literature Cited

    Butcher, G. S. 1990. Audubon Christmas Bird Counts. U.S. Fish Wildl. Serv. Biol. Rep. 90(1): 5-13.

    Carter, M. F., and K. Barker. 1993. An interactive database for setting conservation priorities for western neotropical migrants. U.S. For. Serv. Gen. Tech. Rep. RM-229: 120-144.

    Coughlan, B. A. K., and C. L. Armour. 1992. Group decision-making techniques for natural resource management applications. U.S. Fish Wildl. Serv. Resour. Publ. 185, 55 pp.

    DeGraaf, R. M., V. E. Scott, R. H. Hamre, L. Ernst, and S. H. Anderson. 1991. Forest and rangeland birds of the United States: natural history and habitat use. U.S. Dep. Agric. Handbook 688, 625 pp.

    DeGraaf, R. M., N. G. Tilghman, and S. H. Anderson. 1985. Foraging guilds of North American birds. Environ. Manage. 9: 493-536.

    Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder's handbook: a field guide to the natural history of North American birds. Simon and Schuster, New York, New York. 785 pp.

    Graham, F., Jr. 1990. 2001: birds that won't be with us. Am. Birds 44: 1074-1081, 1194-1196, 1198-1199.

    Hunter, W. C., D. N. Pashley, and R. E. F. Escano. 1993. Neotropical migratory landbird species and their habitats of special concern within the southeast region. U.S. For. Serv. Gen. Tech. Rep. RM-229: 159-171.

    Link, W. A., R. J. Barker, J. R. Sauer, and S. Droege. 1994. Within-site variability in surveys of wildlife populations. Ecology 75: 1097-1108.

    Peterjohn, B. G., and J. R. Sauer. 1993. North American Breeding Bird Survey annual summary 1990-1991. Bird Popul. 1: 52-67.

    Research Working Group. 1992. Preliminary lists of migrants for Partners in Flight. Partners in Flight 2(1): 30.

    Robbins, C. S., D. Bystrak, and P. H. Geissler. 1986. The Breeding Bird Survey: its first fisteen years, 1965-1979. U.S. Fish Wildl. Serv. Resour. Publ. 157, 196 pp.

    Smith, C. R., D. M. Pence, and R. J. O'Connor. 1993. Status of neotropical migratory birds in the northeast: a preliminary assessment. U.S. For. Serv. Gen. Tech. Rep. RM-229: 172-188.

    Tate, J., Jr. 1986. The Blue List for 1986. Am. Birds 40: 227-236.

    Thompson, F. R., S. J. Lewis, J. Green, and D. Ewert. 1993. Status of neotropical migrant landbirds in the midwest: identifying species of management concern. U.S. For. Serv. Gen. Tech. Rep. RM-229: 145-158.

    U.S. Department of the Interior. 1990. Report of the Secretary of the Interior to the Congress of the United States on the Federal conservation of migratory nongame birds pursuant to Section 13 of Public Law 96-366, the "Fish and Wildlife Conservation Act of 1980," as amended. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C. 61 pp.

    U.S. Fish and Wildlife Service. 1985. Revised list of migratory birds. Final rule. Fed. Reg. 50(66): 13708-13722.

    U.S. Fish and Wildlife Service. 1987. Migratory nongame birds of management concern in the United States: the 1987 list. Office of Migratory Bird Management, Washington, D.C. 25 pp.

    U.S. Fish and Wildlife Service. 1990. Conservation of avian diversity in North America. Office of Migratory Bird Management, Washington, D.C. 22 pp.

    U.S. Fish and Wildlife Service. 1992. Species of management concern--1992: preliminary working list--phase 1. Office of Migratory Bird Management, Washington, D.C. 2 pp.

    U.S. Fish and Wildlife Service. 1994. Animal candidate review for listing as Endangered or Threatened species. Fed. Reg. 59: 58982-559028.

    U.S. Fish and Wildlife Service. 1995. U.S. Fish and Wildlife Service ecosystem approach: watershed based units. Division of Realty, Washington, D.C. 2 pp (map).

    Discussion

    Comparison with the 1987 List

    Of the 30 species on the 1987 list, 24 are retained (including 17 for which minor inter-Regional changes are made) and 6 are deleted (3--roseate tern, black-capped vireo, golden-cheeked warbler--because of Endangered or Threatened species listing throughout their ranges since 1987; 3--Harris' hawk, gull-billed tern, ladder-backed woodpecker--because of lack of convincing evidence that continued listing is warranted). Ninety-eight species are added to the list, resulting in a net gain of 92 species and a current (1995) list of 122 species.

    Table 3 provides a side-by-side comparison of the data sources, participants, and selection criteria used in developing the 1987 and 1995 lists.

    Comparison with Other Lists

    Of 122 species on the 1995 National list, 44 are also of high priority on one or more PIF regional lists and 41 are listed as Category 1 or 2 "candidates" in one or more regions. In other words, 44 (17%) of the 254 PIF species (Research Working Group 1992) and 41 (67%) of the 61 bird "candidate" species (USFWS 1994) also qualify as species of management concern. A "preliminary list of species deserving additional conservation measures" found in a 1990 report to Congress (U.S. Department of the Interior 1990) includes 72 species that fall within the focus of this exercise, and 48 (67%) of them qualify as species of management concern.

    Fifteen (79%) of the 19 species on the National Audubon Society's "Blue" list (Tate 1986) are listed here as species of concern, as are 13 (41%) of 32 "Special Concern" species and 4 (21%) of 19 "Local Concern" species. Of 30 species that Graham (1990) suggested "won't be with us" in the year 2001 without renewed conservation attention, 13 (43%) are also on the management concern list (and 15 others are Federally listed as Endangered or Threatened).

    Relationships Among Selection Criteria

    The relationships among the selection criteria are examined by calculating indices of overlap or similarity. EXAMPLE: if two biologists each had 100 books in their offices, and 50 of the titles were identical, the amount of overlap or similarity in the cumulative collection of 200 books would be 50% (i.e., 2 x 50 / 100 + 100). Similar calculations reveal the following amounts of overlap or similarity between various combinations of selection criteria: Delphi and "candidate" 46%, Delphi and PIF 31%, Delphi and BBS 26%, BBS and PIF 25%, BBS and ACBC 23%, BBS and "candidate" 13%, PIF and "candidate" 9%, Delphi and ACBC 8%, ACBC and PIF 8%, and ACBC and "candidate" 0%. On average, the list of species selected by the "candidate" criterion overlapped 31% with the lists selected by the other four criteria, Delphi overlapped 30%, BBS overlapped 22%, PIF overlapped 20%, and ACBC overlapped just 8%.

    Strengths and Weaknesses

    No process designed to identify species at risk is going to satisfy everyone, and that certainly applies to the current document. Many people will question why particular species are not listed. For example, 470 of the 570 species evaluated in the Delphi exercise were considered to be of Moderate or High concern by one or more participants, yet only 72 of them met the Delphi criteria for listing. Others may question the appearance on the list of such widespread and abundant species as the eastern meadowlark and field sparrow, although we believe that their inclusion (based on the BBS criterion) is biologically justified. Overall, we feel that the five-step process yielded a comprehensive and reasonably sound list of species most deserving of additional conservation actions at a national level.

    In particular, we feel that the Delphi exercise was a positive addition to the process. The Delphi exercise has been criticized by some reviewers as being too subjective. Although the process requires that participants make subjective value judgments, the selection criteria (i.e., a score of Moderate or High concern by more than 50% of all (minimum of 5) respondents) is conservative enough to ensure considerable confidence in the results. For example, the cumulative Delphi scores of the 72 species selected by this criterion have a much higher proportion of Moderate and High values than those of all other nongame birds combined (71% vs 15%, P < 0.01). Furthermore, the distribution of Delphi scores of 66 (92%) of the 72 selected species differs significantly (P < 0.05) from that of the nongame bird community at large.

    Some reviewers commented that the combination of BBS and PIF criteria resulted in a bias against wetland birds. Most wetland birds are poorly monitored by the BBS, thus reducing a species' chance of being selected by this criterion, and the PIF criterion specifically excludes most wetland birds from consideration. Despite this bias, two major groups of wetland birds (herons and non-harvested waterfowl, and rails) are represented on the list by larger numbers of species than expected. To guard against potential biases in future lists, it would be beneficial to include a criterion that uses status information from the The Nature Conservancy's Natural Heritage Program. Consideration should also be given to incorporating information from the International Shorebird Survey and the various colonial waterbird databases.

    Primary Reasons for Concern

    Why are listed species considered to be of management concern? To gain some insight into this question, we analyzed the data provided by participants in the Phase II Delphi exercise. Participants were asked to indicate which of five factors were of concern to them. More than one factor could be checked for each species. The 65 species selected in Phase II and examined here received a total of 823 tallies to this question, an average of nearly 13/species (range, 1-30). The primary reasons for concern (i.e., those mentioned by the largest number of Delphi participants) were, in decreasing order:

    a. Known or apparent population declines or range retractions  30 species
    b. Dependence on restricted or vulnerable habitats             21 species
    c. Small populations or restricted range in U.S.               15 species¹ 
    d. Potential impacts of perceived threats                      14 species²

    In the case of the 30 species that were of concern primarily because of known or apparent population declines or range retractions, significant long- or short-term declines have been documented by the BBS for 22 species. The exceptions are black-shouldered kite (poorly sampled), red-shouldered hawk (significant increase), burrowing owl (no detectable trend), common nighthawk (no detectable trend), Bewick's wren (no detectable trend), gray-cheeked thrush (poorly sampled), golden-winged warbler (no detectable trend), and Lawrence's goldfinch (poorly sampled).

    Assuming that concerns for these 65 species are a representative sample of concerns for all 122 listed species, it is apparent that about 46% of the species are of concern because of known or apparent population declines or range retractions, 38% are of concern because of ecological bottlenecks (i.e., this includes the 32% that are dependent on restricted or vulnerable habitats, and the 23% at risk due to small populations or restricted ranges in the United States), and 22% are of concern because of the potential impacts of perceived threats..

    ¹ Includes 4 species listed under "b"
    ² Includes 11 species listed under "a," "b," or "c."

    Nature of Perceived Threats

    Although the potential impacts of threats, whether real or perceived, was the primary cause of concern (i.e., that mentioned by the largest percentage of participants) for only 14 of the 65 species examined, threats were of at least some concern for 62 (95%) of them (Table 3). What is the exact nature of these threats? The primary threats are, in decreasing order:

    a. Habitat loss                                                52 species
    b. Human disturbance                                            9 species¹
    c. Other(unspecified)threats                                    6 species²
    d. Contaminants                                                 2 species³

    If we again assume that this sample is representative of all listed species, expert opinion suggests that habitat loss is a threat to the overwhelming majority (80%) of the species of concern, followed by human disturbance (14%), other (unspecified) threats (9%), and contaminants (3%).

    ¹ Includes 4 species listed under "a"  
    ² Includes 2 species listed under "a" or "b" 
    ³ Both species also listed under "a"

    Attributes of Listed Species

    Do the species of management concern share attributes that distinquish them from other members of the nongame bird community? To answer this question, the distribution of listed species in various guilds and attribute categories is compared with the distribution of all other nongame bird species. Specifically, the following paragraphs compare the BBS guilds of Peterjohn and Sauer (1993), the foraging guilds of DeGraaf et al. (1985), the life-history traits of Ehrlich et al. (1988: xiv-xxiii), and the major taxonomic categories of the American Ornithologists' Union (1983).

    (1) BBS Guilds. (a)Nesting Habitat.--Listed species are not proportionally distributed among the five nesting habitats (P < 0.01). Species in the grassland-nesting guild are over-represented (P < 0.01), while wetland and open water, successional-scrub, woodland, and urban guilds occur in about the proportions expected (P > 0.05). (b) Nest Type.--Species of concern are distributed among the cavity nesting and open-cup nesting guilds in about the proportions expected (P > 0.05). (c) Nest Placement.--Species in the ground and low-nesting guild are over-represented on the list (P < 0.01), while those in the mid-story and canopy nesting guild are under-represented (P < 0.01). (d) Migration Status.--Listed species are not proportionally distributed among the three migration status categories (P < 0.05). Neotropical migrants are over-represented (P < 0.05), permanent residents are under-represented (P < 0.05), and short-distance migrants occur in about the proportion expected (P > 0.90).

    (2) Foraging Guilds. (a) Foraging Substrate.--Species of concern forage on at least 12 of the 20 wetland substrates and all 5 of the terrestrial substrates of DeGraaf et al. (1985). Listed species do not forage proportionally among the three major substrates: wetland, terrestrial, and air (P < 0.05). Wetland-foraging species are under-represented (P < 0.05), while terrestrial- and aerial-foraging species occur in about the proportions expected (P > 0.05). (b) Food Type.--When classified according to 10 major categories of food eaten, the distribution of listed species does not differ from that of all other nongame bird species (P > 0.05).

    (3) Life-History Traits. (a) Clutch Size.--Distribution of clutch sizes of species of concern does not differ from that of the other members of the nongame bird community (P > 0.95). (b) Nest Location.--Listed species are proportionally distributed among the eight major nest location-types (P > 0.10), with the exception that ground-nesting birds are somewhat more abundant than expected (P < 0.10). (c) Nest Type.--Distribution of listed species among the nine major nest types is proportional to the expected distribution (P > 0.10). Species that lay eggs in situations in which they are exposed to visual predators were not more likely to be listed than species that lay eggs in protected situations (P > 0.10). (d) Breeding-Season Diet.--Listed species are proportionally distributed among the eight major breeding-season diet categories (P > 0.25). (e) Chick Development.--Listed species are proportionally distributed among the four chick-development categories (P > 0.10).

    (4) Major Taxonomic Categories. Listed species are not proportionally distributed among the major taxonomic groupings (P < 0.01). The list contains higher-than-expected numbers of herons and non-harvested waterfowl (P < 0.10), diurnal raptors (P < 0.10), rails (P < 0.01), and sparrows (P < 0.05). Pelicans and related species (P < 0.05), and corvids and parids and related species (P < 0.01), are under-represented on the list. Other taxonomic groups occur in about the proportions expected (P > 0.10). Passerines and non-passerines are proportionally represented among the listed species (P > 0.50).

    To summarize, over-represented guilds or attribute categories include the grassland-nesting guild, the ground and low-nesting guild, and neotropical migrants (sensu Peterjohn and Sauer 1994); ground-nesters (sensu Ehrlich et al. 1988); and herons and non-harvested waterfowl, diurnal raptors, rails, and sparrows (sensu AOU 1983). Under-represented groups include the mid-story and canopy nesting guild and permanent residents (sensu Peterjohn and Sauer 1994); birds that forage in wetland substrates (sensu DeGraaf et al. 1985); and pelicans and related species, and crows and chickadees and related species (sensu AOU 1983).

    The Habitat Connection

    Are the species of management concern randomly distributed over the landscape, or are they found in certain habitats or physiographic provinces in greater numbers than expected? This question is addressed by comparing the distribution of listed species in various habitat classifications with the distribution of all other nongame species. Specifically, the following paragraphs compare the 47 forest and non-forest cover types identified by DeGraaf et al. (1991: 531-575), the 69 physiographic regions analyzed in the BBS database (Robbins et al. 1986, as modified; see Butcher 1990), and the 41 USFWS watershed-based ecosystem units located in the contiguous United States (USFWS 1995).

    (1) Forest and Non-Forest Cover Types. (a) Absolute Numbers. The number of listed species found in each habitat (based on Tables 1-5 of DeGraaf et al. 1991) ranges from 4-35, with the central one-half of the values falling in the range of 12-23. Habitats in the top 20% (i.e., those supporting 25 or more listed species) include 1 Eastern Forest cover type (oak-hickory), 5 Great Plains cover types (Gulf prairies & marshes, south Texas shrub grassland, southern plains, central plains, and wetland and riparian), and 3 Western & Southwestern Non-Forest cover types (desert/riparian deciduous woodlands/marshes, annual grasslands/farms, and river/riparian woodlands/subalpine meadows). (b) Relative Numbers. The proportion of listed species (expressed as a percentage of the total number of nongame bird species found in each habitat) ranges from 7-75%, with the central one-half of the values falling in the range of 12-19%. Habitats in the top 20% (i.e., those in which the nongame bird community is composed of at least 20% listed species) include 1 Eastern Forest cover type (oak-hickory), 2 Eastern Non-Forest cover types (pasture/wet or sedge meadow, and everglades/mangroves/tropical hardwoods), 3 Great Plains cover types (southern plains, central plains, and northern plains), and 4 Western & Southwestern Non-Forest cover types (Sonoran desert scrub, Chihuahuan desert scrub, Mohave desert scrub, and annual grasslands/farms). Species of concern are not proportionally distributed among cover types (P <0.05). Listed species are represented in higher-than-expected numbers in Great Plains (P < 0.05) and Western & Southwestern Non-Forest (P < 0.05) cover types, and in lower-than-expected numbers in Western Forest (P < 0.01) cover types.

    (2) BBS Physiographic Regions. (a) Absolute Numbers. The number of listed species found in each physiographic region (and detected on at least 1 BBS route) ranges from 5-32, with the central one-half of the values falling in the range of 14-22. Regions in the top 10% (i.e., those supporting 26 or more listed species) include 1 in the Atlantic Coastal Plain province (Upper Coastal Plain), 3 in the Eastern Piedmont Plateau province (Ridge & Valley, St. Lawrence River Plain, and Great Lakes Transition), 1 in the Appalachian Mountains & Boreal Forest province (Northern Spruce-Hardwoods), and 3 in the Great Plains province (Drift Prairie, Glaciated Missouri Plateau, and Great Plains Roughlands). (b) Relative Numbers. The proportion of listed species (expressed as a percentage of the total number of nongame breeding bird species found in each region) ranges from 6-29%, with the central one-half of the values falling in the range of 15-21%. Regions in the top 10% (i.e., those in which the nongame breeding bird community is composed of at least 23% listed species) include 1 in the Atlantic Coastal Plain province (South Texas Brushlands) and 6 in the Great Plains (High Plains Border, High Plains, Drift Prairie, Glaciated Missouri Plateau, Great Plains Roughlands, and Staked Plains). Species of concern are not proportionally distributed among physiographic regions (P < 0.01). Listed species are present in higher-than-expected numbers in physiographic regions of the Eastern Piedmont Plateau (P <0.05) and Great Plains (P < 0.01) provinces; and in lower-than-expected numbers in physiographic regions of the Western Mountains (P <0.01) and Pacific Slope (P < 0.01) provinces.

    (3) USFWS Ecosystem Units. (a) Absolute Numbers. The number of listed species found in each ecosystem unit (and detected on at least 14 BBS routes) ranges from 2-25, with the central one-half of the values falling in the range of 8-15. Ecosystems in the top 10% (i.e., those supporting 23 or more listed species) include the Arkansas/Red rivers, Upper Mississippi River/Tallgrass Prairie, Great Lakes, and Ohio River Valley. (b) Relative Numbers. The proportion of listed species ranges from 6-36%, with the central one-half of the values falling in the range of 14-20%. Ecosystems in the top 10% (i.e., those in which the nongame breeding bird community is composed of at least 23% listed species) include the Lower Rio Grande, Pecos River, Edwards Plateau, and Texas Gulf Coast. When ecosystems are grouped into six major geographical regions corresponding approximately to FWS administrative regions, listed species are present in higher-than-expected numbers in Southwest (P <0.05) ecosystems; and in lower-than-expected numbers in West Coast (P < 0.01) ecosystems.

    To summarize, over-represented habitats include the Great Plains, and Western & Southwestern Non-Forest cover types (sensu DeGraaf 1991); the physiographic regions of the Eastern Piedmont Plateau and Great Plains provinces (sensu Robbins et al. 1986, as modified; see Butcher 1990); and ecosystems in the Southwest (sensu USFWS 1995). Under-represented habitats include the Western Forest cover types (sensu DeGraaf 1991); the physiographic regions of the Western Mountains and Pacific Slope provinces (sensu Robbins et al. 1986, as modified; see Butcher 1990); and the ecosystems of the West Coast (sensu USFWS 1995).

    The reader is cautioned against placing too much importance on the results of these preliminary analyses. We present this information merely as an interesting way of looking at the list, and hope that it will encourage others to undertake similar, but more rigorous, exercises to identify and prioritize avian habitats needing management attention.

    A Look at Species Groups of Concern

    Thus far, we have been concerned with identifying species of management concern, as mandated by the Fish and Wildlife Conservation Act. However, we recognize that there may be occasions when it would be useful for land managers to know if there are certain species groups that are generally considered by the "experts" to be of greater concern than others. This question was addressed by examining the distribution of 10,250 scores submitted by participants in the Delphi exercise. The 599 species evaluated by the 60 participants were aggregated into 40 taxonomic groups (orders, families, or subfamilies) of varying sizes, and the proportion of Moderate and High scores in each group was compared to the expected value of 22%. For example, 43% of the scores submitted for five species of loons were Moderate or High. Since this proportion is much larger than expected by chance (P < 0.01), loons might be considered a species group of management concern. Similar calculations revealed that 10 other species groups also had larger-than-expected proportions of Moderate or High scores, and therefore might also be considered of concern (except where indicated, all P values are < 0.01): grebes (32%), ciconids and non-harvested anserids (34%), rails and limpkins (84%), terns (41%), alcids (28%, P < 0.05), columbids (53%), cuculids (37%), owls (33%), caprimulgids (43%, and shrikes (58%). Twelve species groups had lower-than-expected proportions of Moderate or High scores, and might be considered to be of little or no concern (except where indicated, all P values are <0.01): sandpipers (17%), gulls (4%), woodpeckers (12%), larks and swallows (12%), corvids (5%), parids and relatives (12%), nuthatches and creepers (5%), sylviids (9%), waxwings and phainopeplas (0%), tanagers (12%, P < 0.05), icterids (16%), and finches (8%). The proportion of Moderate and High scores in the following 17 species groups did not differ from the expected value of 22% (all P values are > 0.10): albatrosses and procellarids, storm-petrels, pelecanids, falconids, plovers and relatives, swifts, hummingbirds, trogons and kingfishers, tyrannids, wrens and dippers, turdids, mimids, motacillids, vireos, warblers, cardinalids, and emberizids.

    Once again the reader is cautioned against placing too much importance on the results of these preliminary analyses. We present this information merely for comparison with the list of species of management concern, and as an alternative way of assessing species groups at risk, and encourage others to undertake similar, but more rigorous, exercises to identify avian species groups in need of priority management attention.

    Management Recommendations

    While the species identified in this document are believed to be of high priority for additional research and conservation actions, we do not believe that it is appropriate to focus conservation actions (including management and research activities) on these species to the exclusion of all others. For example, on an individual basis, most species of shorebirds, beach-nesting terns, and marsh-nesting birds did not rank out as species of National concern. Still, there is little doubt that the habitats used by these assemblages should be high priorities for management and protection.

    On a regional basis, a certain amount of discretion and flexibility should be applied in using this document to provide guidance to local managers and landowners. For example, it is conceivable that in some situations, species not listed in Table 1 may be of sufficient concern at a local scale (e.g., physiographic regions, States, USFWS Regions) to still warrant priority action. Conversely, it is likely that certain species of "concern" in a given Region (Table 1) will be relatively low priority for management action. Table 1 can be used to coordinate management efforts on those species that occur in more than one Region, and to track progress in meeting management goals.

    Earlier, reference was made to the need to protect the habitats and ecological communities upon which the "species of management concern" depend. Accordingly, it is suggested that Table 1 be used, in concert with other available information (e.g., Western Hemisphere Shorebird Reserve Network sites, atlases of colonial waterbird breeding sites, etc.), to identify avian habitats most in need of management attention.

    Acknowledgements

    This report was authored by John L. Trapp. I thank Stan Senner and Susan Drennan of the National Audubon Society for their support and encouragement. For their participation in the Delphi process, I owe a special debt of gratitude to the 33 American Birds Regional Editors and selected others (Raymond Adams, Stephen Bailey, Gordon Berkey, William Boyle, Kenneth Brock, Jim Cox, Richard Davis, Bruce Deuel, Walter Ellison, Jeff Gilligan, Jim Granlund, George Hall, Greg Jackson, Hugh Kingery, Rudolf Koes, David Lambeth, H. Landridge, Greg Lasley, Ron Martin, Guy McCaskie, David Muth, Blair Nikula, Richard Paul, Wayne Peterson, Robert Pyle, Thomas Rogers, Christopher Siddle, Stephen Stedman, David Stejskal, Peter Taylor, Daryl Tessen, Thede Tobish, Richard West, and Sartor Williams), the 7 USFWS Regional Coordinators (Richard Coon, Stephanie Jones, Steve Lewis, Kathleen Milne, Diane Pence, Kent Wohl, and Tara Zimmerman), and the 22 area experts (Bob Armstrong, Robert Askins, Vernon Byrd, Ellen Campbell, Terry Doyle, David Ewert, Elizabeth Flint, Daniel Gibson, Scott Johnston, Rod King, Brian McCaffery, Joe Myers F. Nùñez-García, Thane Pratt, Michael Reed, Jorge Saliva, Fred Schaffner, Tom Snetsinger, Robert Snydam, F. J. Vilella, John Wright, and Fred Zeillemaker). Richard Coon, William Howe, Stephanie Jones, Steve Lewis, Diane Pence, Kent Wohl, and Tara Zimmerman helped develop the selection criteria and provided helpful comments on several earlier drafts of this report.

     

     

     

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    Last updated: April 11, 2011