Ne:Otropigalmigr:Ant Landbird Monitoring Program for Maineand..New' Brunswick: Assessing Coastal Importance and Management Strategies
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NE:OTROPIGALMIGR:ANT LANDBIRD MONITORING PROGRAM FOR MAINEAND..NEW' BRUNSWICK: ASSESSING COASTAL IMPORTANCE AND MANAGEMENT STRATEGIES Norman Famous, Wildlife Ecologist PROJECT SUMMARY Populations of many Neotropical migrant landbirds and shorebirds have shown both long and short-term declines in the Northeastern U.S. and adjacent Canada. The causes of these declines are not entirely understood and vary among species. A cooperative initiative linking Federal and Provincial agencies, private landowners, conservation organizations, industry and field ornithologists was implemented in 1993 to monitor breeding and migratory bird populations in structurally stable boreal forests, pine-spruce woodlands, bogs and fens in the Bay of Fundy ecological zone in Maine and coastal New Brunswick, as well as the Acadian Peninsula in NW New Brunswick. Careful selection of monitoring sites and control of observer expertise are being exercised. Most sites are relatively free from future habitat fragmentation, large changes in habitat structure, human disturbances and insect infestations. The distribution of birds and vegetation characteristics are being mapped within fixed diameter point count circles along 25 new census routes located within 0.5 km of the coast or on larger islands. Birds were censused and mapped along 13 BBS routes in the region. Twenty-two boreal bogs and fens were surveyed. Habitat use by birds and habitat changes over time will be evaluated in addition to long term population trends in both new routes and BBS routes. Breeding season bird use and vegetation change in nine mined peatlands undergoing natural and human-induced restoration are being monitored in Maine and New Brunswick. (Comment, the habitat work was not completed during subsequent years due to insufficient funds.) Seventy-eight fall migration fixed-diameter area-search point count circles were censused every ten days from August through October at six coastal sites. Many of the same species as well as 10 poorly monitored high-priority species that breed in northern Canada and winter in the tropics are being monitored (Blancher el al. 1993). International Shorebird Surveys were conducted in association with fall migration point counts at several important shorebird staging areas. Both breeding season and fall migration area-search point counts monitor species not currently monitored by other methods. Sample sizes adequate for statistical analysis were obtained, or should be obtained with increased sampling in 1995, for 44 species (28 Neotropical migrants) recorded on coastal breeding season point count routes. Sufficient sample sizes should also be obtained for an additional eight species (six Neotropical migrants) by pooling coastal point counts with the 13 BBS route data. Twelve species (four Neotropical migrants) are reported to be undergoing statistically significant long-term population declines in USFWS's Region 5 (includes study area). Nine more (eight Neotropical species) have shown non-statistically significant declines and 28 (19 Neotropical species) have either stable or increasing population trends. An additional seven species including three Neotropical migrants that are exhibiting significant/long-term regional population declines were less-frequently sampled. 1 Preliminary' resulfsshow poputation differences,some ;arge, between:years.~i£'Significent '. breeding season findings included large population changes in BickneWs thrush (found on seven coastal point count routes in 1993, but were absent in 1994) and steady numbers between years for merlin and boreal chickadee. Two disjunct clay-colored sparrows were detected at opposite ends of New Brunswick. Among Neotropical migrants, bay-breasted warbler numbers dropped dramatically while blackpoll warbler numbers increased. Among short-distant migrants, white-throated sparrow, song sparrow, red-breasted nuthatch, hermit thrush and pine siskin showed declines, probably a result of the severe winter of 1993/94. Rarely quantitatively documented, habitat selection for most migrant birds closely paralleled habitat selection during the breeding season throughout all fall migration sampling areas. Geographic trends in distribution of yellow-rumped warbler and the frugivorous feeding guild were directly related to available food resources and to a geographic barrier (Frenchman's Bay). The six migration monitoring sites were not high concentration areas. Preliminary analysis of the migration point count data show decreased numbers of bay breasted warblers and increased population numbers of yellow-rumped and black-throated green warblers, flycatchers and savannah sparrows. Not surprising, population trends for several migrants paralleled migration season trends. Decreased numbers during breeding and migration of several short-distant migrants such as white-throated sparrow, song sparrow, swamp sparrow, white-crowned sparrow, American goldfinch, and pine siskin were probably correlated to the severe winter in SE United States. Shorebird surveys on this and concurrent studies showed dramatic regional declines for semipalmated sandpiper, semipalmated plover, and ruddy turnstones and smaller declines for short-billed dowitcher and black-bellied plover over the past 15-20 years. Steady or increased populations of whimbrel and white-rumped sandpipers occurred over the same time interval. Additional funds are needed to conduct vegetation surveys and evaluate bird-habitat interrelationships. Relationships among vegetation cover type, vegetation structure, height, and density and bird use will be evaluated. Background The decline of Neotropical migrant landbirds is of global concern. Populations of North American Neotropical migrants have declined due to a variety of reasons, most of which appear to be human-related. The magnitude of these declines is being critically examined (Smith et a/. 1993, Peterjohn and Sauer 1994, Sauer et a/. 1994) and the causes are being evaluated in breeding, migrating and wintering habitats by a variety of investigators (Askins et a/. 1990, Rappole and McDonald 1994). This study, initiated in 1993, is examining long term population trends and changes in habitat characteristics during the breeding season and fall migration in coastal spruce-fir forests, pine-spruce woodlands, bogs and fens in eastern Maine and coastal New Brunswick. For quality assurance, censusing protocol calls for fixed-diameter point counts conducted in controlled habitat types by highly-qualified observers. The preliminary results of the first two seasons are summarized in this report. Cooperative studies bringing together high-profile conservation organizations, private landowners, corporate sponsors, and Provincial and Federal land managers are needed to address the plight of Neotropical migrant land birds whose habitat requirements have no 2 ···politicallownershipboundaries. Managemenfdecisioris affecting land use.requireaccur8t~,· reliable long-term data on bird populations and vegetation changes which this study is evaluating. In addition, existing BBS population trend data collected under less rigorous protocol, without concurrent vegetation and land use analysis, need to be critically evaluated. This study will provide a means of accomplishing these tasks. The study is divided into 6 components: 1) Breeding Season Point Counts, 2) Fall Migration Point Counts, 3) Shorebird Surveys, 4) Data Compilation and Analysis, 5) Breeding Season Vegetation Analysis, and 6) Fall Migration Vegetation Analysis. Tasks 1-3 have been completed for both years, data are partially compiled, and tasks 4 and 5 are in progress. Additional funds are needed to complete data analysis and to conduct a detailed vegetative survey. This report summarizes the preliminary analysis of tasks 1-3. Data entry and analysis are ongoing. Data are available for individual routes/point counts upon request. Objectiv~s • to continue long-term monitoring of Neotropical and short-distant migrants in discreet ecological zones in the Bay of Fundy region in Maine and the Bay of Fundy and Bay of Chaleur regions in New Brunswick, • to monitor species, mostly Neotropical migrants, under-sampled by the BBS within the region (15 species) and Canada (9 species) or reported to be declining (39 species), • to concurrently monitor habitat/vegetation change within point count locations, • to evaluate and compare habitat selection and usage during the breeding and migration seasons, • to complement and enhance the results and interpretation of Breeding Bird Survey data for the spruce-fir forest biome, • to monitor disjunct populations of Bicknell's thrush and blackpoll warbler and a regionally unique population of breeding merlins, • to monitor vegetation recovery and bird use in mined bogs, • to monitor declining migrant shorebird populations, and • to enhance Watchable Wildlife and education opportunities on lands managed by conservation organizations, private landowners and government agencies. 3 Cooperating'.. Organizati6ns Th~ cooperating groups include the U.S. Fish and Wildlife Service, U.S. Navy, Acadia National Park, New Brunswick Department of Natural Resources and Energy, Roque Island Gardner Homestead Corporation, Roosevelt Campobello International Park, the Canadian Sphagnum Peat Moss Association, The Nature Conservancy, Maine Coast Heritage Trust, Maine and National Audubon Societies, Stanton Bird Club, and corporate sponsors including Bausch and Lomb, Leica, and Sony International. Monitoring Avian Productivity Survivorship (MAPS) sites will be