Kenneth V. Rosenberg ¹ and Jeffrey V. Wells ²

INTRODUCTION

Setting regional conservation priorities is an important step in the Partners in Flight (PIF) planning process. At the regional level, prioritization may represent a conflict between global needs of the entire population of a species and local concerns or pressures. The PIF species prioritization scheme (Carter et al., this volume) provides an objective means for assessing the relative conservation concern for bird species throughout the United States. Applying these priority rankings to local or regional conservation planning efforts requires detailed knowledge of species’ distributions and relative abundances, so that the geographic areas most important to high-priority species in each region can be identified.

The Northeast region is relatively small and homogeneous, compared with other PIF planning regions. Largely covered with deciduous and mixed conifer forests, this region comprises all or part of 16 physiographic areas, and supports substantial populations of many Neotropical migratory landbirds (NTMB) typical of eastern forests. The earliest studies suggesting that certain species of NTMBs were declining originated in the northeastern U. S. near Washington, D. C. (Johnston and Winings 1987, Robbins 1980, Briggs and Criswell 1978, Lynch and Whitcomb 1978). Since that time, a host of studies throughout the region have examined the question of whether population declines have occurred and why (Askins et al. 1990, Hagan and Johnston 1992, Askins 1993). Except for reviews by Askins et al. (1990) and Smith et al. (1993), no studies have attempted to establish conservation priorities for NTMBs from the perspective of the entire Northeast region. None have considered populations in the Northeast in relation to their entire ranges or total population. None have incorporated up-to-date, region-wide databases (Breeding Bird Survey [BBS], Breeding Bird Atlas [BBA]) to develop region-wide priorities or conservation recommendations. Consequently, land managers remain confused about which species are of greatest concern or conservation priority, and in which areas our efforts should be concentrated.

Building upon the work of Carter et al., we present a scheme for prioritizing NTMBs and determining which geographic areas in the northeastern U. S. are most important for their conservation. The need for a document summarizing the status of NTMBs in the Northeast and outlining regional priorities grew out of: (1) formalization of the Northeast regional planning process of PIF; and (2) the common need, expressed by many states in the Northeast, for assistance in implementing regional priorities at the state level. This paper summarizes our prioritization process; the complete results of these efforts may be found in Rosenberg and Wells (1995).

Our scheme differs from PIF's national prioritization database in that it explicitly considers the importance of the entire region to the total population of each species as the primary criterion for establishing conservation priority. We then consider each species' population trend and local distribution within the region to assess degree of regional concern and to identify areas of greatest importance for high-priority species. This information will serve as the framework behind a Northeast regional conservation plan.

METHODS

The Northeast Region of PIF, defined as U. S. Fish and Wildlife Service (USFWS) Region 5, includes the states of Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. This region also includes portions of 16 physiographic areas (Fig. 1), derived from BBS Physiographic Strata and used in PIF)conservation planning.

Figure 1. Map of physiographic areas of eastern North America, showing the 16 areas represented in the Northeast Region. Note, some physiographic area boundaries and numbers have changed after 1996.

to view a larger version of this image, click on it

Our basic approach is to draw together and integrate several existing databases on NTMBs in the region, roughly following the procedure outlined by Smith et al. (1993) in their preliminary assessment of NTMB status in the Northeast. This "regional-filter" approach integrates abundance and trend data from the BBS with state-level BBA data to identify species of regional importance and concern, based on the proportion of total species populations that are supported in the region and their population trends. For those species with relatively high proportions of their populations in the Northeast, we then determine areas of most concentrated occurrence, based on distribution of occupied atlas blocks. Important geographic areas are defined as those with the highest concentrations of the highest-ranking species. We next identify which of these species also are declining, and identify areas with the highest concentrations of declining species.

This information ultimately will be combined with land-classification programs, such as GAP Analysis, to simultaneously assess the status of bird populations and their habitats. We believe that synthesizing available data on NTMBs using the resources at hand is important now, in anticipation of GAP analysis completion. Our analysis is intended to be a working document that will provide the raw materials for conservation planning in the Northeast.

Prioritizing species—importance of area

Percent of range—We began the process of determining importance of area by considering the percentage of each species’ range lying within Region 5. Because of PIF's early emphasis, we consider only Neotropical migratory species; future revisions will include all landbird species. After reviewing many existing published range maps, we determined that the most up-to-date, detailed, and readable maps available for all species are those in the Peterson (1980, 1990) field guides. From these range maps, we estimated the percent of each state or province occupied by each bird species. We then multiplied these percentages by the area (sq. mi) of each state. By summing these areas we derived an estimate of total range size for each species. We then summed the areas for the states within Region 5 and divided by the total range area to determine the percent of range in the Northeast (see Rosenberg and Wells 1995, Appendix 1). Because this method does not compare portions of the entire range to one another, it protects against biases caused by map projection distortions.

Percent of population—A more accurate measure of the importance of an area to a species’ long-term probability of persistence is the percent of the total species population (Wells and Richmond 1995) that occurs within that region. Although in practice this measure is difficult to obtain, an index that reflects percent of population can be formulated by weighting range areas derived from the above procedure with relative abundances from BBS data. We multiplied the range area occupied in each state and province by the relative abundance for that area. We then summed the values for states within the Northeast region and divided by the sum for all areas occupied to determine the percent of total population in the region. Note that this procedure also yielded an index of total population size for each species.

We obtained BBS relative abundances for all states, provinces, and physiographic areas directly from the BBS database (Sauer et al. 1996). These values represent average numbers of birds counted on all BBS routes in each geographic area from 1966 through 1994. Note that we make several assumptions when using BBS relative abundances that could bias our estimates of populations sizes (B. Peterjohn, pers. com.). First is that detectability of a species does not vary across all the geographic areas in our analysis. Also, large changes in relative abundance over the 29 yr period could result in overestimates or underestimates of percent of population, and therefore importance, in a given area. For example, if a species has declined greatly in a physiographic area, using the long-term average abundance may greatly underestimate the true importance of that area to the species’ total population. Our estimates of total populations are probably most accurate for those species that occur primarily in the continental U. S. and southern Canada, and are least accurate for those species with extensive portions of their range in Canada above the region covered adequately by the BBS.

Regional importance of geographic areas

BBAs provide the most detailed and up-to-date information on the distributions of species within individual states or provinces. To incorporate this finer scale resolution into our importance of area rankings, we estimated the percent of BBA blocks occupied in portions of physiographic areas within each state. Atlas data for this analysis were available in published form or were made available from Connecticut (Bevier 1994), Delaware, Maine (Adamus no date), Maryland, Massachusetts, New Hampshire (Foss 1994), New York (Andrle and Carroll 1988), Pennsylvania (Brauning 1992), Rhode Island (Enser 1992), Vermont (Laughlin and Kibbe 1985), Virginia, and West Virginia (Buckelew and Hall 1994). We also used published Atlases or atlas data from adjacent regions (Kentucky, Ohio [Peterjohn and Rice 1991], Michigan [Brewer et al. 1991], Ontario [Cadman et al. 1987], and the Canadian Maritimes [Erskine 1992]) to complete our analysis of physiographic areas that extend beyond the borders of Region 5.

We computed an "area importance score" to identify areas within the Northeast Region with highest concentrations of the highest-priority bird species. First, for each bird species, we "normalized" the percent Atlas-block occupancy across the 44 state/physiographic area units (see Rosenberg and Wells 1995, Appendix 4); the area with the highest percent occupancy was set to 100, and each other area unit was expressed relative to the maximum occupied unit. Then, for each of the 44 areas, we summed the importance rankings of each bird species, divided by its relative percent occupancy of Atlas blocks, to compute an overall importance score:

area importance score =

species rank % occupancy max. % occupancy

These scores also were normalized (i. e., the highest score set to 100) to reflect relative importance of each of the 44 areas in the Northeast.

Incorporating population trends

We used population trend estimates to identify those species that have high proportions of their total populations in the Northeast and that are declining (or increasing) significantly in geographic areas of interest. We obtained estimates of population trends for NTMBs in Region 5, and for each state and physiographic region, directly from the BBS Lab (Sauer et al. 1996). These trend estimates were updated in spring 1995 and are based on BBS data from 1966 through 1994. They therefore represent the most up-to-date estimates available, and supersede any previously published BBS results (e. g., Robbins et al. 1986, Peterjohn and Sauer 1993, 1994). Trends were calculated (by BBS Lab) using the Linear Route-Regression method, modified with estimating equations (Link and Sauer 1994), and are expressed as a percent change per year.

We combined estimates of regional trends with our previously determined percent of total population to compute a "species concern score" for each declining species. This score was calculated as:

species concern score =

(% of population) (trend) total population size

where the total population size was estimated by summing relative abundances times the area occupied for each state and province.

Finally, to identify geographic areas with the highest concentrations of high-concern species, we calculated an "area concern score" based on the percent Atlas-block occupancy of each declining species in each state/physiographic area unit:

area concern score =

(species concern score) (% Atlas-blocks).

These area concern scores were then normalized (i. e., highest score set to 100) to represent relative concern among the 44 areas in the Northeast.

RESULTS

Percent of population and range in the Northeast

We estimate that 34 species have =15% of their population in the Northeast region (Table 1). This analysis identified three species (Bicknell’s Thrush, Scarlet Tanager, Worm-eating Warbler), for which the Northeast supports > 50% of the population; ten other species have >25% of their population in the region. Our cut-off of 15% is somewhat arbitrary; an additional 15 species have between 10% and 15% of populations. These include mostly widespread species such as Song Sparrow, Common Yellowthroat, and Chimney Swift, which happen to be abundant in the Northeast. These species may be considered of moderate priority in regional planning.

Table 1

Initially we had identified 44 species with >10% of their range in the Northeast (see Rosenberg and Wells 1995, Table 1). When population size was considered, the importance of the Northeast to several of these species was enhanced (relative to percent of range alone) . For example, even though Scarlet Tanager is a widespread species, its high relative abundance in several northeastern states suggests a much higher percent of population in the region than predicted from geographic range alone (60% vs. 21%). Other species that gained considerably in importance compared with their percent of range included Gray Catbird (39% vs. 10%), Eastern Phoebe (31% vs. 11%), Cerulean Warbler (30% vs. 12%), Solitary Vireo (23% vs. 11%), and Northern Oriole (16% vs. 7%). Species with higher relative abundances outside the Northeast dropped in importance rank, however; these included Henslow’s Sparrow, Chestnut-sided Warbler, Canada Warbler, and Whip-poor-will. Still others (e. g., Nashville Warbler, Grasshopper Sparrow) dropped off our importance list because the bulk of their populations are outside our region.

The resulting list of 34 top-ranked species (Table 1) is diverse, both taxonomically and ecologically, and includes species of both northern and southern affinities. The largest group represented are the wood warblers (14 species); other "typical" NTMBs include 3 flycatchers, 3 thrushes, and 3 vireos. Although most of the list can be considered forest species, several important species of grasslands and successional habitats are represented. Even among the top 10 species are birds of coniferous mountaintops, deciduous bottomland forests, shrubby clearings, and pastures. Clearly, no obvious suite of species associated with a particular habitat type stands out as being of highest conservation priority.

Shared importance with adjacent regions

To determine which regions to consider in collaborative conservation planning for NTMBs, we compared percentages of total populations in the Northeast with those in adjacent USFWS Regions and Canada (Appendix 1). The clearest result of this analysis is the overriding importance of Canada to NTMBs. Among all NTMBs that breed in the Northeast, 42 species have >50% of their population within Canada, and 29 species have >75% of their population there. For 16 species, Canada supports >90% of the total population. Among the top 34 ranked species in the Northeast, almost half have the largest proportion of their population in Canada. For Black-throated Blue, Blackburnian, and Canada warblers, Ontario and Quebec alone hold 40 – 70% of the total population (Rosenberg and Wells 1995, Table 5). For Bicknell’s Thrush, at least 1/2 of the total range is in Quebec and the Maritime provinces. Clearly, any conservation plan for northern forest birds in the Northeast must seek cooperation with Canadian provinces, although populations may be larger in the U. S.

Among other Regions in the U. S., Region 4 (Southeast) is next in terms of shared importance with the Northeast. Twenty shared species have >50% of their population in Region 4 (recall that only 3 species had >50% in Region 5). Of the 34 top-ranked species, 9 have the highest proportion of their population in Region 4; the most important examples are Hooded Warbler (82%), Yellow-throated Vireo (55%), Northern Parula (52%), Louisiana Waterthrush (51%), Cerulean Warbler (51%), and Wood Thrush (46%).

Region 3 (Midwest) is important for several highly ranked species. Henslow’s Sparrow, Golden-winged Warbler, and Whip-poor-will have >50% of their population in this region, which also ranks highest in importance for Blue-winged Warbler, Field Sparrow, and Northern Oriole. For Golden-winged Warbler, Wisconsin and Michigan hold 59% of the total population, and Michigan, Ohio, and Wisconsin support nearly 80% of the total population of Henslow’s Sparrow.

This analysis clearly shows that collaboration with Canada, the Southeast, and Midwest regions will be important for the conservation of NTMBs in the Northeast.

Important Geographic Areas

Having identified species for which the Northeast is particularly important, our next step was to highlight the most important geographic areas for bird conservation in the Northeast. Based on relatively high atlas-block concentrations of high-priority species among state/physiographic area units (Table 2), the most important areas occur in several disjunct blocks (Fig. 2). The first includes the Northern New England and Northern Spruce-Hardwood Forest portions of Vermont and New Hampshire. This area is important because of high concentrations of Bicknell's Thrush, Scarlet Tanager, Wood Thrush, and Black-throated Blue Warbler. Adjacent portions of Maine, Massachusetts, Connecticut, and New York are classified as of secondary importance.

Table 2

Figure 2. Map of important state/physiographic area units in the Northeast, based on high atlas-block concentrations of high-priority NTMB species. Red areas are those with area importance scores > 75 (see Table 3); pink areas scored 70-75. These areas represent those where long-term planning for regionally important populations is most needed.

The second major area of high importance includes all of West Virginia, and adjacent highland and Ridge and Valley portions of Maryland. Note that the contiguous Ohio portion of Ohio Hills also is classified as of highest importance. This area supports among the highest relative concentrations of Scarlet Tanager, Worm-eating Warbler, Louisiana Waterthrush, and Wood Thrush, our 2nd through 5th-ranked species. In addition, the New York portion of the Allegheny Plateau was classified of relatively high importance because of moderate concentrations of many priority species.

Note that in this analysis, very small areas may tend to receive greater importance ranks because Atlas coverage my have been more complete there, resulting in greater percentage occupancy for many species than is shown in larger, more diverse areas. Combining small areas with adjacent portions of the same physiographic area probably would give a more accurate assessment of their importance.

Incorporating population trends

Overall, it appears that the high-priority species identified in the Northeast are not the same species for which population declines have generated so much concern within PIF. Of the top 12 high-ranked species (other than Bicknell's Thrush) which have at least 30% of their total population in the Northeast, only three show significant long-term declines since 1966 (Fig. 3). Of the 6 most important species, only the Wood Thrush has declined. Overall, two-thirds of the 34 priority species are stable or increasing.

Figure 3. Relationship between percent of total population in the Northeast and long-term population trend for 34 NTMB species. Species below the dotted line are declining significantly, according to BBS data.

Species showing the steepest declines (>5% per year) region-wide are Henslow's Sparrow, Golden-winged Warbler, and Canada Warbler. Of the 11 declining species, about half are species of successional habitats or forest edge. Declining forest birds include Wood Thrush, Cerulean Warbler, Canada Warbler, Eastern Wood Pewee, and Black-and-white Warbler. Solitary Vireo has shown the largest significant increase in the region, and Yellow-bellied Sapsucker and Ovenbird also have increased significantly since 1966.

Among the total list of NTMBs that breed in the Northeast, 35 species (31%) show significant long-term declines of at least 1% per year, whereas 15 species (13%) have increased significantly (Table 3). Among this list of declining species, 67% are birds of primarily open (non-forest or successional) habitats. Of the top 10 species with the steepest declining trends, only 2 (Olive-sided Flycatcher, Canada Warbler) can be considered forest species. In contrast, of the top ten increasing species in the region, all but two are forest species. This pattern of greater declines in non-forest species in the Northeast previously has been noted (Askins et al 1990, Witham and Hunter 1992, Askins 1993, Franzreb and Rosenberg 1997).

Table 3

These trends highlight the dichotomy between importance of regional populations (and therefore responsibility of the Northeast region to conserve them) and population declines (which may dictate concern and conservation action). In general, the most important species are not declining, and the most steeply declining species do not have large proportions of their populations in the Northeast. The implications of this dichotomy will be discussed further below.

Species of conservation concern

Some species do have important populations in the region and also are declining. Combining information on importance of regional populations and their trends, our concern scores identified four species that stand out as being in need of immediate conservation action (Table 4). The Henslow's Sparrow score was much higher than that of any other species because of the small total population of the species, relatively large proportion in the Northeast, and precipitous declining trend. Immediate planning and active management for this sparrow should be a high regional priority. Golden-winged Warbler was second in terms of regional concern, followed by Worm-eating and Cerulean warblers. Although the declining trend for Worm-eating Warbler was not statistically significant, any potential declines are of concern because of the small population of this species and its high importance in the region. Louisiana Waterthrush, Whip-poor-will, and Canada Warbler were ranked as species of moderate concern. Other species such as Wood Thrush, which receive attention because of their declining trend, scored much lower—indicating less of an immediate concern from a global perspective.

Table 4

Conservation "hot-spots"

Our final procedure was to identify geographic areas that support high concentrations of species designated as high concern. This process identified only one highest-priority "conservation hot-spot" within the region (Table 2; Fig. 4). This area encompassed the Ohio Hills portions of West Virginia and Pennsylvania (and also Ohio), and the adjacent Cumberland Plateau portion of West Virginia. All four of the highest concern species occur in relatively high concentrations in this area. Surrounding areas formed a "second-priority hot-spot" (Fig. 4). Areas to the north on the Allegheny Plateau and Great Lakes Plain ranked highly because of high concentrations of Henslow's Sparrow and Golden-winged Warbler, whereas areas to the east (Ridge and Valley) have high concentrations of Worm-eating and Cerulean Warblers.

Figure 4. Map of conservation "hot-spots," based on high atlas-block concentrations of NTMB species with high species-concern scores. Black areas represent state/physiographic areas with area concern scores > 60 (see Table 2); gray areas scored > 30. These areas are those where immediate conservation action for regionally declining bird populations can best be implemented.

Note that the highest priority area also is one of the two areas identified as regionally important in terms of concentrations of highly ranked species (regardless of trend). The other high importance area in northern New England was not identified as an area of high immediate conservation concern (Table 2). Realize, however, that we lack population trend estimates for Bicknell’s Thrush; a declining trend for that species would elevate northern New England to highest-concern status. Most coastal areas from Virginia to southern New England did not rank highly in terms of either regional importance or concern for declining species. These coastal areas, however, may be extremely important as migration stopover sites for birds breeding to the north, and they support important communities of widespread grassland species that independently have been recognized as a conservation priority (Askins 1995, Wells and Rosenberg in press).

DISCUSSION

Any scheme to assign conservation priorities to species or sites necessarily is based on a number of assumptions and must be interpreted with caution. The numbers, scores, and ranks that we have generated are not absolute; rather they are intended to illustrate relative importance from a regional or global conservation perspective. Because our results may appear to differ from the widely accepted scheme of Carter et al. (this volume), and because the critical reader may question certain aspects of our analysis, we will address several issues and concerns related to prioritization. In the end, we want to stress that there is no one "best list" of priority species; each approach will generate a list that should elicit particular conservation actions. In this regard, our analysis has highlighted a dichotomy between species of long-term regional responsibility and those of immediate conservation concern, which we discuss below.

Importance of area—the "regional filter" approach

By considering importance in the entire Northeast region as a means of selecting species for further consideration in conservation planning, we have employed a "regional filter" approach to species prioritization. Species with high proportions of their total population in the region initially rank highly in our analysis, regardless of their population trend or threats to their habitats. Highly ranked species that also show declining population trends are of greatest immediate conservation concern. We believe that conservation actions and dollars can be directed most efficiently at those species for which the region can significantly influence global population status or trends.

The PIF prioritization scheme (Hunter et al. 1993, Carter et al. this volume) is intended to inform managers at state and local levels about the global significance of their lands and to give federal and international policy makers the information needed to preserve entire species. In its most recent form, the prioritization scheme ranks species according to a variety of factors, some of which are considered global factors (e. g,. threats on nonbreeding grounds) and some of which are area specific. Among the latter, the Area Importance score reflects the abundance of a species within an area relative to its rangewide abundance. For example, if a species was relatively abundant on BBS routes in a given state, then the state would receive a high Area Importance ranking for that species. Although this scheme will provide an overall priority ranking based on equal consideration of all factors, it may be preferable to give greater initial weight to particular factors that reflect local status. For example, by first listing species with high Area Importance scores in a particular state or physiographic area, managers can focus on those species that they can effectively conserve.

Small states in the Northeast face a particularly difficult dilemma in trying to prioritize conservation strategies for NTMBs. We understand that state fish and wildlife agencies have a mandate to preserve the species found within their state borders. Therefore, each state must consider the importance of its own lands for the persistence of the species within their state. A state such as Rhode Island could opt to put efforts either into preserving species at high risk of extirpation within the state, without consideration of their global status, or into managing species that are widespread and abundant within the state (i. e., with high Area Importance scores), but that are exhibiting regional or global population declines. Ideally, Rhode Island could enter into partnerships with other New England states to help conserve bird populations on a larger scale. Prioritization of species and habitats at the regional level will facilitate this process by providing a larger perspective for local decisions.

One of our goals in this analysis was to provide a quantitative evaluation of Area Importance at regional, state, and physiographic-area scales that incorporates both the percentage of the total range and various measures of relative abundance (see Rosenberg and Wells 1995 for discussion of species' status in individual states and physiographic areas). Basing conservation strategies on the total species population usually is not considered feasible for small, migratory landbirds. The analogy of waterfowl management in North America, however, illustrates the importance of a global perspective. The successful North American Waterfowl Management Plan (USDI 1986) explicitly considers the total population of each species, including breeding potential, limiting factors, and seasonal and geographic variation in habitat use. Strategies for management (providing habitat, setting harvest limits) are then apportioned among the migratory flyways, USFWS regions, states, and individual wildlife refuges. Provisions for state and local needs exist, and conflicts between local and national goals may arise, but the ultimate goal of conserving waterfowl populations is accomplished at an international scale.

Similarly, conservation of migratory songbirds cannot be accomplished in a piecemeal manner, with each local entity solely responsible for setting priorities and carrying out actions. Although the knowledge necessary to craft an analogous conservation plan for NTMBs is fragmentary and difficult to attain, this remains the ultimate goal of PIF. By drawing together extensive, existing data on the distribution, status, and relative abundance of each species, we have made the first attempt to provide such a global perspective for NTMBs in the Northeast.

Assessing population trends—controversy and consensus

Although importance of area rankings may identify bird species most appropriate for long-term, regional conservation planning, setting priorities for short-term management requires knowledge of species' status or population trends at regional or continental scales. At present, the only dataset available for evaluating changes in abundance of land bird populations at these scales, over a relatively long time period, is the BBS (Robbins et al. 1986, Droege 1990, Butcher et al. 1993, Sauer 1993).

Like all datasets, the BBS has certain limitations that can complicate trend analysis. The various limitations of the BBS dataset have been discussed by a number of authors (e.g. Droege 1990, Geissler and Sauer 1990, James et al. 1990, O'Connor 1992, Butcher et al. 1993). Despite these limitations, with proper analytical techniques the BBS dataset can yield important trend information. Recently, much controversy has centered over which analytical techniques are appropriate for studying trends in BBS data. The BBS Lab's statisticians developed a technique called the Linear Route-Regression method (Geissler and Noon 1981, Geissler and Sauer 1990), which was modified with estimating equations estimates (Link and Sauer 1994). Others have criticized this technique and have applied other methods of analyzing BBS trend data (e. g., James et al. 1990, O'Connor 1992, Lauber and O'Connor 1993, Wiedenfeld et al. 1992, James et al. 1996).

Although much has been made of the controversy between these schools of thought (see James et al. 1996, Thomas 1996), no comprehensive, quantitative comparison of the results of the different methods has yet been published. A full review of the controversies regarding BBS data and its analysis is beyond the scope of this paper. We believe, however, that problems with data and discrepancies among results of different analytical techniques have been overstated and exaggerated by some authors.

From what we have seen of the various critiques mentioned above, the overall result of determining which species are exhibiting long-term, region-wide trends seems little affected by choice of analytical method. For example, all studies of BBS trends have concluded that Wood Thrushes and Cerulean Warblers have experienced long-term, steady population declines. Although caution must be used when interpreting BBS trends for smaller geographic areas or shorter time periods, a conservative approach to conservation planning suggests that erring on the side of concern for potentially declining species is best. Important, long-term, regional declines, such as those evident in Cerulean Warbler, Golden-winged Warbler, and Henslow's Sparrow, are usually unambiguous, and are verifiable from data other than the BBS.

Responsibility versus concern: A dichotomy in landbird conservation

In this paper we have identified bird species and geographic areas that are "important" or "high-priority" for two very different reasons. The reasons behind these priority rankings lead to two very different kinds of conservation action. Some species are important because a high proportion of their total population resides in the Northeast region. Some areas within the Northeast are important because, from a global perspective, they support high relative concentrations of these same important species. Importance or priority for these species or areas can be interpreted as the responsibility of managers in a given state or physiographic area to conserve the populations of those species, or similarly, their ability to affect the entire populations of these species through conservation planning or action. As an example, Scarlet Tanager is a widespread species with (mostly) stable populations, but also is a species for which the Northeast Region has a high responsibility for conserving. Conservation planning in areas with high local abundances or concentrations of Scarlet Tanagers (e. g., West Virginia, Pennsylvania, Allegheny Plateau) can have a large effect on the total population of this species.

Another set of bird species can be considered important because their populations are experiencing long-term declines in the region. From a global perspective, declining species are of greatest concern if they also have a large proportion of their population in the region of decline. Geographic areas with high concentrations of these important and declining species become conservation "hot-spots." As an example, Henslow's Sparrow has only a moderate proportion of its population in the Northeast (ranked 19 out of 34 species), but its populations are declining precipitously. Concern for this species, therefore, is higher than for any other in our analysis, and areas with relatively high concentrations of Henslow's Sparrows (western Pennsylvania and New York, Great Lakes Plain) become extremely important from a regional or global perspective.

The dichotomy, then, is between concern for declining species, which leads to immediate conservation action, and responsibility for species with high proportions of their population in the region, which leads to long-term conservation planning. The PIF regional landbird conservation plan being developed for the Northeast is considering both types of priority and action.

ACKNOWLEDGMENTS

This paper represents a portion of a report submitted to the USFWS Region 5 office in Hadley, MA; we are grateful to Diane Pence and the USFWS for funding this project. We thank members of the Northeast Working Group of Partners in Flight for their initial suggestions that served as the basis for this project, and for their comments at our presentations to regional meetings. For help in providing state Breeding Bird Atlas information, we thank Roger Clapp (Virginia), Steve McRae (Massachusetts), Brainard Palmer-Ball, Jr. (Kentucky), Ann Raspberry (Maryland), Glenn Therres (Maryland), Winston Wayne (Delaware), Richard West (Delaware). For providing BBS data, advice, and maps, we thank Sam Droege, Bret Hoover, Sandy Orsillo, Bruce Peterjohn, and John Sauer. We benefited from advice and discussions about Neotropical migrants with Rick Bonney, Mike Carter, André Dhondt, George Fenwick, John Fitzpatrick, Chuck Hunter, Larry Niles, David Pashley, Diane Pence, Dan Petit and Tom Sherry, among others. We also thank Lynda Field, Pat Hanley, and Allison Childs Wells for help in compiling data and constructing tables and appendices. David Pashley, Chuck Hunter, and Rick Bonney made helpful suggestions that improved this manuscript.

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Appendix 1

¹ Cornell Lab of Ornithology
   159 Sapsucker Woods Rd
   Ithaca, NY 14850

¹ National Audubon Society
   c/o  Cornell Lab of Ornithology
   159 Sapsucker Woods Rd
   Ithaca, NY 14850