Draft 2008
A Plan for Monitoring Shorebirds During the Non-breeding Season in Bird Monitoring Region Pennsylvania – BCR 13
Version 1
2008
1
Draft 2008
Table of Contents
Introduction 3
Methods 5
Results - Shorebirds 7
Site Descriptions – Pennsylvania 8
Presque Isle State Park 8
Shenango Reservoir 11
Figures and Tables
Figure 1. Conceptual framework for integrated bird monitoring. 3
Figure 2. Shorebird Planning and Bird Conservation Regions in Canada and the United States. 4
Figure 3. PRISM sites in BCR 13, 14, 30, 27, and 31. 5
Table 1. Focal shorebird species for BCR 13.. 7
Introduction
The bird conservation initiatives - waterbirds, waterfowl, shorebirds and landbirds - are cooperating to design a comprehensive “integrated bird monitoring” (IBM) program for Canada and the United States. The conceptual framework for IBM (Fig. 1) includes strong emphasis on detecting species at risk and helping to protect them. These broad goals are achieved by estimating population trends and defining requirements for viable populations. These objectives in turn are accomplished by population modeling based on population levels, demographic rates and habitat information. Population trends are estimated by surveying breeding populations whenever possible, and by surveying the species for which this is not feasible at other times of year. Surveys of all species are made throughout the year to help identify and monitor use of suitable habitat.
Figure 1. Conceptual framework for integrated bird monitoring.
Most surveys in upland habitats are designed at a large spatial scale (e.g., southern Canada and the United States) and do not require detailed information at the local level. Surveys of wetland habitats, in contrast, must be carefully designed to insure that the habitat is well covered, and different methods may be needed in different environments. A series of “regional assessments” is thus being prepared to help design the wetland surveys. Regions were formed by intersecting a Bird Conservation Region (BCR) map with a Province and State map, deleting small polygons and smoothing the borders (Fig. 2). The resulting “Bird Monitoring Regions” can be used to scale up results to either BCRs or Provinces and States.
Figure 2. Shorebird Planning and Bird Conservation Regions in Canada and the United States.
Adapted from: USFWS-U.S. Shorebird Plan and CWS-Canadian Shorebird Conservation Plan
The regional assessments summarize current information about wetland bird distribution, abundance, habitat relationships and timing of use within the Region and identify information needed to design reliable monitoring programs. These “needed pilot studies” are then prioritized by people concerned with monitoring birds in the region and a plan is developed to carry out the work. Carrying out the pilot studies is expected to take 1-3 years. Long-term surveys will then be implemented. Additional details are provided in “Managers Monitoring Manual” available at http://www.pwrc.usgs.gov/monmanual/techniques/shorebirdsnonbreedingsites.htm. More information on regional progress can be found at the U.S. Shorebird Plan’s Regional Conservation Plan website (http://www.fws.gov/shorebirdplan/RegionalShorebird.htm).
Methods
Focal wetland species of shorebirds were first identified. The initial list included all wetland species of shorebirds that are common or abundant at any time of year within the Region, according to Brian Harrington, based largely upon data from the International Shorebird Surveys (ISS) and the US Shorebird Conservation Upper Mississippi Valley/Great Lakes (BCR 13) Regional Plan. Sites in which any of the focal species are common or abundant at any time of year were then identified using a list prepared for this project and supplemented by information provided by birding guides, ornithologists and birders knowledgeable of the Region. Most sites were single areas, such as a National Wildlife Refuge or Audubon Important Bird Area, but dispersed sites, such as “lakes >10 ha”, could also be identified.
Figure 3. PRISM sites in BCR 13, 14, 30, 27, and 31.
The International Shorebird Survey (ISS) provided species numbers for some of the identified sites. The ISS is a volunteer based survey initiated in 1974 by Brian Harrington. Volunteers select their survey sites and are given guidelines on census frequency and data collection for spring and fall migration. The ISS guidelines ask volunteers to survey once every 10 days from April 1st to June 10th for spring migration, and once every 10 days from July 11th to October 31st for fall migration. ISS records provided the maximum counts recorded for species where the identified site is also an ISS site.
Survey methods for sites include appropriate tide levels for surveys, if that information is available. Tide levels for surveys are based on the advice of biologists and birders with knowledge about the sites. Due to the different geography of the sites, different tide levels
are recommended to concentrate the birds for a survey. While high tide at one site may bring in birds that are spread out over an expansive area at low tide, high tide at another site may completely cover the habitat or food resources and scatter the birds elsewhere. Therefore, different tide levels may be recommended for different sites.
Additional site information may also include information about visibility. Excellent/good visibility simply means that the birds can be seen without obstruction clearly enough to identify to species, either by physically getting close enough or with a good scope or binoculars.
Maps showing land ownership, roads and wetlands were prepared for the region. Maps of each site were also prepared and information useful in designing surveys for the focal species was presented. The survey objective was assumed to be estimating the average number of birds of each focal species present within the site during a specified interval. Up to three types of habitat were described for each focal species: Type 1 habitat, outlined in purple on the maps, included regularly-used areas that should be sampled using a well-defined sampling plan. Type 2 habitat, which was outlined in red, included areas used sparingly by the focal species. Type 2 habitat is not surveyed as often or with rigorously defined methods, but is surveyed less formally every few years to document continued low use by the focal species. Type 3 habitat receives virtually no use by the focal species during the study period and is not surveyed as part of the monitoring program. Requests, however, are circulated for any records of the focal species occurring in substantial numbers in these areas.
A description of each site was prepared with the following headings:
Boundaries and ownership
Focal species using the site and timing of use
Location of type 1 and 2 habitat within the site
Access to the type 1 and 2 habitat and visibility of the birds
Past and current surveys
Potential survey methods
Description
Selection bias
Measurement error and bias
Needed pilot studies
We assume for any survey that the study area and study period (within years) have been defined. The goal of the survey was assumed to be estimating the trend, across several years, in the average number of birds present during the study period. Bias means a long-term trend in the ratio (number recorded)/(average number present). Selection bias ensues when some portion of Type 1 habitat has zero chance of being surveyed, usually due to access problems, and there is a long-term trend in the proportion of birds using the non-sampled portion. Exclusion of some Type 1 habitat does not necessarily cause selection bias because trends in the sampled areas might be the same as trends in the non-sampled areas. Anytime some portion of Type 1 habitat could not be included in the sampled areas, the potential for selection bias and ways to reduce it were discussed. Measurement error means not detecting all birds present in the surveyed area at the time of the survey. Measurement bias is a long term trend in the proportion of birds present at the time of the survey that are detected on the survey. Measurement error does not necessarily cause measurement bias because the proportion of birds detected might not change through time. Anytime measurement error was probable, its magnitude and probable stability through time were discussed along with ways to reduce the proportion of birds missed on the surveys.
Results - Shorebirds
Table 1. Focal shorebird species for BCR 13. The list includes Tier A (general occurrence and high concern) and B (local occurrence and/ or lower concern) system. The list was expanded to include all species that received either high or medium ratings of concern in the American or Canadian Shorebird Plans.
Tier / Breeders / MigrantsA
B / Piping Plover*
American Woodcock
Upland Sandpiper
Wilson’s Phalarope / Whimbrel*
American Golden-Plover
Hudsonian Godwit*
Marbled Godwit*
Buff-breasted Sandpiper
Sanderling
Solitary Sandpiper
Short-billed Dowitcher
Red Knot*
Black-bellied Plover
Dunlin
Semipalmated Sandpiper
Greater Yellowlegs
Lesser Yellowlegs
Least Sandpiper
* indicates species that are extirpated as breeders (Piping Plover) or that overfly the BCR, and are noted rarely as they stop only occasionally to rest. Little direct management activity other than some basic habitat protection can be undertaken for these species.
2
Draft 02/07
Site Descriptions – Pennsylvania
Presque Isle State Park
Description: Presque Isle is a long-shore drift-formed peninsula that extends northeastward into Lake Erie from the city of Erie. Totaling roughly 3200 acres, the peninsula spans just 600 to 1500 feet for much of its 3 mile neck, then widens to ¾-1 mile in width by 3 miles in length. The south shore of the larger part of the peninsula essentially runs parallel to the Erie shoreline, and at its narrowest point is separated by a narrow channel. The peninsula in effect shelters the City of Erie shoreline and Presque Isle Bay. Presque Isle is Pennsylvania’s only dune and shoreline habitat.
Presque Isle has up to 4 million visitors a year, making it one of the most heavily used Parks in the country. The park is open to many aspects of recreation, including boating, swimming, hunting and hiking, and human disturbance is one of the most obvious threats to nesting and migrating birds.
The Park is composed mainly of broadleaf deciduous vegetation (oak, maple, cherry, willow and cottonwood) and freshwater marshes. Between the peninsula and the mainland is the sheltered Presque Isle Bay. While Presque Isle is not associated with flowing waters, steady winds regularly affect the water levels around the Park up to 10 to 12 inches, varying available shorebird habitat as often as from one day to the next.
Many of the thousands of waterfowl and waterbirds that use the area actually use the sheltered Presque Isle Bay. Shorebirds, however, are usually observed at Gull Point, the roughly 319-acre tip of Presque Isle. Thirty-nine species of shorebirds have been observed along a narrow stretch of shoreline here, including up to 1500 individuals. Shorebirds can be observed during both the fall and spring migration periods. Presque Isle seems to serve mainly as a roosting site rather than a feeding site (Jerry McWilliams, Pers. Comm., February 2006). It may be that food sources are in shorter supply at Gull Point relative to other places, due to substrate composition. Large numbers of shorebirds are typically seen resting here during stormy weather.
Sixty five acres of Gull Point have been closed to the public since 1994 from late spring to early fall as protected shorebird habitat, but is under pressure from Park users to be reopened to the public for hiking and boating purposes. Just under four miles of shoreline at Gull Point are designated Critical Habitat for the piping plover. Piping Plovers historically nested there and continue to use the area as transients. Enforcement of the beach closure at gull point is difficult, and disturbance does occur. Breakwaters built offshore along the north side of Presque Isle around 15 years ago have significantly slowed sand deposition at Gull Point with the purpose of retaining sands at the beaches west of Gull Point. As a result, beach habitat is slowly being lost due to plant succession.
Maximum count data from ISS records (~1977-2006) are as follows:
Priority – A Species / Spring / Fall / Priority – B Species / Spring / Fall / Other Species / Spring / FallAGPL / 7 / 17 / BBPL / 25 / 62 / KILL / 15 / 75
AMWO / 1 / 2 / DUNL / 350 / 400 / SPSA / 30 / 15
BBSA / 2 / 3 / GRYE / 32 / 25 / WILL / 3 / 3
HUGO / 2 / 32 / LESA / 400 / 70 / RUTU / 31 / 135
MAGO / 1 / 4 / LEYE / 75 / 30 / SESA / 430 / 230
PIPL / 3 / 2 / SEPL / 45 / 50 / WRSA / 7 / 13
REKN / 52 / 60 / WIPH / BASA / 14 / 8
SAND / 108 / 350 / PESA / 18 / 120
SBDO / 880 / 35 / STSA / 2 / 30
SOSA / 11 / 2 / LBDO / 1 / 6
UPSA / 2 / 1 / DOsp. / 1 / 7
WHIM / 110 / 74 / COSN / 135 / 12
REPH
RNPH
WIPH
WESA
Management: Pennsylvania State Parks, Presque Isle Audubon Society, Audubon IBA, SubFocus Area of the North American Waterfowl Management Plan, proximity to Long Point, Ontario (field base of Bird Studies Canada), Pennsylvania Breeding Bird Atlas.
2
Draft 02/07
Access: Access into the Park is via roads which go up the neck and encircle most of the outer edge of the peninsula. The 65-acre Special Management Area is accessible only by special permit holders from April 1 to November 30. This includes shorebird monitors, park staff, US Fish & Wildlife Service and Pennsylvania Game Commission biologists.