During the last year our project continued to be recognized for the valuable role we play in monitoring shorebird populations of the New World. Although we cannot claim to have done a perfect job, we can take pride in knowing that we are the only international project in our hemisphere which is actively and consistently collecting information to document what is happening to shorebird numbers. Although our program design has not been ideal for monitoring populations (see later article in this newsletter), we know that your efforts and our efforts have combined to build the best record of shorebird population numbers in the world. Notwithstanding this expression of pride, we also need to consider ways of doing a better job. Our newsletter this year includes discussion of the growing need to track what is happening to shorebird populations, always with an eye to finding ways to stem declines shown in a summary below. We also share miscellaneous news we have learned, and some good news like the following item.
The Great Arctic Reserve, comprising an area the size of Switzerland on the Arctic Tundra of the Taymyr Peninsula (North-Central Siberia), was created by Resolution 431 of the Russian Government. Establishment of the Reserve has been advocated by a number of organizations involved with shorebird conservation and research. The area is the breeding zone and/or migration stopover site for many of the shorebirds which spend their winter on the Atlantic coasts of Europe and Africa. In summer 1994 expeditions were organized from the Netherlands and other countries to visit Siberia to study nesting shorebirds. Future expeditions are planned.
The Pan American Shorebird Program (PASP) has been revived. If you see any color marked shorebirds, please try to identify the colors and positions of the markers, the geographic location of the bird, and date, and send this information to Dr. Cheri Gratto-Trevor, Canadian Wildlife Service, 115 Perimeter Rd. Saskatoon, SK S7N 0X4 Canada. Cheri will do her best to find the original bander of the bird so that both you and the bander can communicate with each other.
For our Western and Central American cooperators, Pat Baird (Dept. Biology, California State University, Long Beach, CA U.S.A. 90840) has asked that we watch for color-marked Least Terns. If you find one, try to note the colors and locations of the color bands on the legs and send a letter to Pat
Special thanks are due to Ellie Winslow, Carol Wilder, Pauline Patton and Meg Doherty all of whom are the volunteers who have managed and maintained the processing of your shorebird reports. When we receive your report Brian Harrington goes over it to see if he has any questions about what you have reported. The report then joins a file for acknowledgment, which hopefully you receive within 2 weeks of having sent in your report. The report then awaits keying into databases. As recently as 18 months ago we had an enormous backlog of reports awaiting keying. Thanks to the hard work of the team, we are now UP TO DATE (wow! and more exclamations!) with keying. Later the database is printed, and error-checked against your original report to find and eliminate any mistooks that mahavey occurred. Of course, we do not mook mistiks. Finally, when all this is done, the paper files will make their way into the fire-proof vault at Manomet Observatory for use should any later verifications be needed. The proofed and corrected data entry file is then added to the main ISS file where it remains available for research and conservation needs.
Do you want to do even more work for the ISS? Most of the important shorebird habitats we know of in the US are wetlands. When wetlands stand to be modified, whether for functions such as housing or commercial development, or for functions such as wildlife management, dredge-spoil deposition in harbors and rivers, etc. approval for the modification is needed from the U.S. Army Corps of Engineers. Each application for a "Section 404" wetland permit is given public notice, with an opportunity for public comment. At Manomet we have been reviewing notices issued by the New England Division of the Corps in order to watch for applications for projects which we feel might seriously affect large numbers of shorebirds. In the rare instances we find applications which concern us, we respond with written comments.
Unfortunately, we cannot review all notices for all areas of the country. We are uncertain of the number of applications that may occur in different regions of the country, but reviewing the New England applications requires about an hour a week. The regional offices we are seeking coverage for are in the following states: MS, TN, LA, MO, NY, MD, VA, WV, KY, PA, GA, SC, FL, AL, NC, CA, TX, NM, AR, and OK.
We are looking for persons willing to receive and to screen notices, and then to alert us of projects which seem to seriously threaten shorebird populations. We will notify the Corps., and perhaps other organizations, of our concerns when appropriate issues are identified. If you (or someone you know) would be willing to review "Section 404" permits for us, we would be glad to hear from you. Thanks.
Adding a new bent to the International Shorebird Surveys. In another article in this newsletter we summarized published information showing how shorebird populations have fallen according to information in literature. The review included
information from the ISS which was published in 1989, as well as information published in 1993 from the Maritimes Shorebird Survey (MSS), a project has been operated by the Canadian Wildlife Service in close coordination with the ISS. To date, all of the evaluations of population trends have shown either declines or no change; none have shown population increases. The declines have occurred across a broad spectrum of species, and there is no pattern to suggest that any particular habitat is involved, or that any particular region is an obvious source of the declines.
It seems clear from the evaluations that there are broad-scale population declines occurring among a variety of species. It also is very likely that there are ongoing declines in many more species than we have demonstrated. Why do we say this?
The most simple answer to this question is that none of the surveys which have been used for evaluating population trends were designed for this purpose. For instance, the ISS and the MSS have aimed to gather information that would show major zones of shorebird migration and principal times of migration for common species. We do not want to burden our readers with a description of the statistical quagmire that is involved in using the ISS data for evaluating changing populations of shorebirds, but bottom line, there need to be very large changes in the bird populations before we can detect them. We are convinced that we need refine our ability to detect population change, and that we need to begin reorganizing operation and goals the ISS so that the information we collect will be more powerful for assessing population change, or in other words, so that we will be able to detect change earlier than we currently can do.
The ISS is staffed largely by volunteers, and so has been operated so as to minimize data sampling restrictions that might interfere with cooperators' bird watching enjoyment. Thus the program has achieved very broad coverage, but sampling protocols needed for uses such as population trend monitoring were not employed. It is time to begin modifying protocols at sites selected to provide more useful data for population monitoring over the long term. Wildlife refuges, because of their protection, staffing and managed status, are an ideal focus for this effort. We have decided to begin a trial project in the Northeastern US, which within the Fish and Wildlife Service is known as Region 5, because of its high human density and good volunteer resources. We made this decision based on the volunteer participation we have had in the ISS over the last 20 years (See accompanying figure which shows the number of sites in each Fish and Wildlife Service Region). ISS data have been collected at about 900 locations within the contiguous 48 United States; 375 of these are within the USFWS Region 5 (see Figure), including refuges that are important to shorebirds.
Another analysis of ISS data showed that many of the key migration staging areas used by shorebirds during passage through the United States are National Wildlife Refuges. This, in combination with the fact that we can expect refuges to remain undeveloped in decades to come, make refuges, and similar governmental lands, a logical target for a special ISS project aimed at population monitoring.
We have not yet settled on what new protocols we will set up during the next year. For now we are simply pointing out the need for change, and anticipating the addition of a special project focused on refuges. We will keep you posted, and include an extra newsletter after the 1995 migration season is ended.
Shorebirds: Status, and Trends East of the 105th Meridian
The following are excerpts from a paper prepared at Manomet for the National Biological Survey 1995 publication of Our Living Resources
Many shorebirds migrate by using a 'stepping-stone' strategy; they visit 'staging sites' where they accumulate fat before continuing with a long-distance, nonstop flight to the next site. The fat accumulated at staging areas provides fuel for the subsequent flight. Growing evidence (Schneider and Harrington 1981) indicates that staging areas are unusually productive sites with highly predictable but seasonally ephemeral 'blooms' of invertebrates, which the shorebirds use for fattening. In some cases, especially for 'obligate' coastal species, specific sites are used traditionally. In other species, especially those which have staging sites in nonmarine habitats, major staging area locations may shift between alternative sites between years, perhaps responding to annual variables such as water levels or variations of spring phenology. Whichever situation prevails, it is clear that high proportions of entire populations of some species may use one or a small number of staging sites (Morrison and Harrington 1979; Senner and Howe 1984; Harrington et al. 1991). Because of this, conservationists believe that some species' populations are at risk through loss of strategic migration sites (Myers et al. 1987). Other species evidently are threatened by loss and/or lost use of breeding habitat (Haig and Plissner 1993, Page et al. 1991). Still others evidently are threatened by loss of wintering habitat (Leachman and Osmundson 1990).
Monitoring shorebird population trends is warranted for other reasons as well. Predicted consequences of global warming include substantial changes of sea level (Lester and Myers 1989). This will strongly affect intertidal marine habitats, which many species of shorebirds depend upon. Another prediction is that some of the strongest warming effects will be at high latitudes, which includes the latitudes where many shorebirds migrate to breed as well as south temperate latitudes, where many of them winter. A third prediction is that the relative synchrony of seasonal events at different latitudes will change. For example, Spring phenology at Arctic latitudes may advance by 3 weeks, but only by a week at temperate migration staging sites. The 'stepping stone' migration strategy that most shorebirds employ must have an evolutionary basis in a highly predictable relationship between seasonal events at widely distant latitudes.
Information on population trends in North American shorebirds comes largely from studies designed for other purposes, except in the case of a few species that breed within latitudes covered by the Breeding Bird Survey (BBS) and one game species, the American woodcock. We divide these studies into two types, those based on surveys during (1) breeding and (2) nonbreeding seasons. Population trend evaluations have been completed for 27 of the 41 species (listed with scientific names in Table 1) of shorebirds common east of the 105th Meridian.
Population trend data from breeding seasons come mostly from studies of declining or threatened species such as piping plover (Haig and Plissner 1993), mountain plover (Graul and Webster 1976; F. L. Knopf, U. S. Fish & Wildlife Service, unpublished data) and snowy plover (Page et al. 1991). There is no recent, reliably documented sighting of an Eskimo curlew, the only endangered North American shorebird. Additional data come from the BBS and from special survey efforts of game species such as American woodcock (Sauer and Bortner 1991).
Nonbreeding season data from east of the 105 th Meridian come mostly from aerial surveys of migrants on Delaware Bay during Spring (Clark et al. 1993), of migrants by the International Shorebird Surveys during Spring and Fall (Harrington et al. 1989), and by the Maritimes Shorebird Surveys (MSS) in eastern Canada during Fall (Morrison et al. in press). Although none of these projects was designed principally to gather data for population trend monitoring, they are the only databases on migrant species that have been systematically compiled through a period of years. An exception is the Christmas Bird Counts which are conducted when most shorebirds are south of the United States. To err on the side of caution in evaluating these data, a population trend change at the P<0.10 level was considered to be statistically significant; these are noted as pluses (+) for increases and minuses (-) for decreases in Table 1.
Results and Discussion
The resources that have been applied to tracking shorebird numbers pale in comparison to efforts spent on waterfowl and other game birds. Nonetheless, largely voluntary efforts of the International Shorebird Surveys (ISS) of Manomet Observatory, the Maritimes Shorebird Survey (MSS) of the Canadian Wildlife Service, the Breeding Bird Survey (BBS) of the National Biological Survey, and surveys on Delaware Bay (DELBAY) coordinated by New Jersey and Delaware state wildlife agencies, have produced coarse data that are useful for trend analysis. Inasmuch as the BBS is conducted during the breeding season and is based on roadside surveys, its value is greatest in analyzing population change of broadly distributed shorebirds common in temperate latitudes where survey effort is greatest. The ISS, MSS, and DELBAY projects have focused on migration season counts and, therefore, are the best (though not ideal) available resources for monitoring northern-breeding shorebirds, which includes the majority of species in North America.
Plovers. Three of the eight species of plover that regularly occur east of the 105th Meridian (snowy plover, piping plover and mountain plover) are species of concern (endangered, threatened or candidate species); killdeer and perhaps black-bellied plover are in decline (Table 1). In North America, all of these except the black-bellied plover are distributed principally in temperate latitudes; snowy, piping, and mountain plovers breed in special, localized habitats (principally sandy beaches and salt lakes/salt flats for snowy/piping, short-grass prairie for mountain). There has been no evaluation of trends for Wilson's plovers, typically a beach-nesting species in southern North America. There are no statistically significant population changes in lesser golden and semipalmated plovers.
Oystercatchers, Avocets, and Stilts. No significant population changes have been detected in the three species of these groups east of the 105th Meridian (Table 1).
Sandpipers. This is the largest family of shorebirds. Five of the 28 species in Table 1 (willet, upland sandpiper, long-billed curlew, marbled godwit, and American woodcock) commonly breed in the contiguous 48 United States; two (long-billed curlew, which nests principally in short-grass prairie and American woodcock (second-growth woodland)) show significant population trend declines. Upland sandpipers (tall grass habitats, including croplands) show a significant increase. The remaining 23 sandpiper species breed principally north of the contiguous 48 states; six of these (ruddy turnstone, red knot, sanderling, white-rumped sandpiper, baird's sandpiper, and buff-breasted sandpiper) are principally high-latitude breeders, and two (red knot and sanderling) of the three species for which trend analysis data are available were in decline (Table 1). The 16 remaining species can be grouped as taiga and/or middle Arctic breeders; seven of these have not been evaluated for population trend change, and five species (whimbrel, semipalmated sandpiper, least sandpiper, short-billed dowitcher, and common snipe) were found to be in significant decline (Table 1), and four species (greater and lesser yellowlegs, spotted sandpiper, and dunlin) showed no significant change (Table 1). No species showed significantly increased population trends.
Phalaropes. Only one (Wilson's phalarope) of the three species of North American phalaropes has been evaluated for population change, and it showed significant declines (Table 1).
Summary and recommendations. Population trend evaluation has been conducted for 27 of 41 shorebird species common in the United States east of the 105th Meridian. In Table 1 we have grossly classified the principal habitat used by each species within this defined area as a first step in considering whether population trends correlated with types of habitats used. Of the 27 species for which trend data are available, 12 show no change, one increased, and 14 decreased (Table 1). There were no clear correlations with habitat.
As described earlier, shorebird populations are important to be monitoring nationally. Yet because most species inhabit difficult-to-access regions for much of the year, they are difficult to monitor during summer breeding and winter nonbreeding periods. Migration seasons appear to be the most practical time for monitoring most species. Unfortunately, sampling for population monitoring during nonbreeding seasons presents a group of unresolved analytical challenges. Additional work on existing data can help identify how (whether) broad, voluntary/professional networks can collect data that will better meet requirements for monitoring population change.
Table 1. Species, major habitats, and population change ('-' for declining status, '+' for increasing status) in North American breeding shorebirds in the United States east of the 105th Meridian.
Tables are a real bear on the Internet so we are going to use the following format instead:
Binomial name/Common name/Habitat/Ref.& status/Significance
Codes for the references are listed at the bottom of the table.
Pluvialis squatarola/Black-bellied plover/Coastal/a-; d+/P<.10(a); ns(d)
Pluvialis dominica/Lesser golden plover/Upland/d-/ns
Charadrius alexandrinus/Snowy plover/Coastal/g threatened/
Charadrius wilsonia/Wilson's plover/Coastal/unk/
Charadrius semipalmatus/Semipalmated plover/Mixed/a-; d+/ns(a); ns(d)
Charadrius melodus/Piping plover/Coastal/c threatened/
Charadrius montanus/Mountain plover/Upland/b+/ns
Haematopus palliatus/American oystercatcher/Coastal/unk/
Himantopus mexicanus/Black-necked stilt/Fresh water/b-/ns
Recurvirostra americana/American avocet/Fresh water/b-/ns
Tringa melanoleuca/Greater yellowlegs/Mixed/a-/ns
Tringa flavipes/Lesser yellowlegs/Mixed/a+/ns
Tringa solitaria/Solitary sandpiper/Fresh water/unk/
semipalmatus/Willet/Coastal/a+, b+; d-/ns(a), ns(b), ns(d)
Actitis macularia/Spotted sandpiper/Fresh water/b+/ns
Bartramia longicauda/Upland sandpiper/Upland/b+/P<.05
Numenius phaeopus/Whimbrel/Coastal/a-; d+/P<.01(a); ns(d)
Numenius americanus/Long-billed curlew/Upland/b-/P<.05
Limosa haemastica/Hudsonian godwit/Coastal/unk/
Limosa fedoa/Marbled godwit/Mixed/b+/ns
Arenaria interpres/Ruddy turnstone/Coastal/a-;d+;e-/ns(a), ns(d), ns(e)
Calidris canutus/Red knot/Coastal/a-;d-;e-/ns(a);P<.10(d);ns(e)
Calidris pusilla/Semipalmated sandpiper/Mixed/a-;d-;e-/Ns(a);P<.02(d);
Calidris mauri/Western sandpiper/Mixed/unk/
Calidris minutilla/Least sandpiper/Mixed/a+;d-/ns(a);P<.05(d)
Calidris fuscicollis/White-rumped sandpiper/Mixed/unk/
Calidris bairdii/Baird's sandpiper/Fresh water/unk/
Calidris melanotos/Pectoral sandpiper/Fresh water/unk/
Calidris maritima/Purple sandpiper/Coastal/unk/
Calidris himantopus/Stilt sandpiper/Fresh water/unk/
Tryngites subruficollis/Buff-breasted sandpiper/Upland/unk/
Limnodromus griseus/Short-billed dowitcher/Coastal/a-;d-;e+/P<.05(a);P<.08(d); P=.12(e)
Limnodromus scolopaceus/Long-billed dowitcher/Fresh water/unk/
Gallinago gallinago/Common snipe/Fresh water/b-/P<.05
Scolopax minor/American woodcock/Special/b-;f-/P<.05(b);P<.05(f)
Phalaropus tricolor/Wilson's phalarope/Fresh water/b-/P<.05
Phalaropus lobatus/Red-necked phalarope/Special/unk/
Phalaropus fulicaria/Red phalarope/Special /unk/
a=Howe et al. (1989) for the years 1972-1983; b=Peterjohn, unpublished analysis, Breeding Bird Survey, National Biological Survey, 1982-1991; c=Haig and Plissner, 1993; d=Morrison et al, in press for years 1974-1991; e=Clark et al., 1993 for the years 1986-1992; f=Sauer and Bortner, 1991; g=United States Fish and Wildlife Service, Office of Endangered Species, unpublished.
Clark, K.E., L.J. Niles, & J. Burger. 1993. Abundance and distribution of migrant shorebirds in Delaware Bay. Condor 95:694-/705.
Forbush, E.H. 1912. Game birds, wild-fowl, and shore birds. Massachusetts State Board of Agriculture, Boston, 622 pp.
Graul, W.D., and L.E. Webster. 1976. Breeding status of the mountain plover. Condor 78:265-267.
Haig, S.M., and L.W. Oring. 1985. Distribution and status of the piping plover throughout the annual cycle. Journal of Field /Ornithology 56:334-345.
Haig, S., and J.H. Plissner. 1993. Distribution and abundance of piping plovers: results and implications of the 1991 /international census. Condor 95:145-156.
Harrington, B.A., J.P. Myers, and J.S. Grear. 1989. Coastal refueling sites for global bird migrants. Pages 4293-4307 in O.T. Magoon, H. Converse, D.Miner, L.T. Tobin, and D. Clark, editors, Proceedings of the sixth symposium on coastal and ocean /management 5:4293-4307. American Society of Civil Engineers, NY.
Howe, M.A. , P.H. Geissler, and B.A. Harrington. Population trends of North American shorebirds based on the International /Shorebird Survey. Biological Conservation 49:185-200.
Lester, R.T., and J.P. Myers. 1989. Global warming, climate disruption, and biological diversity. Pages 177-221 In W.J. /Chandler, editor, Audubon Wildlife Report 1989/1990, Academic Press, NY.
Morrison, R.I.G., and B.A. Harrington. 1979. Critical shorebird resources in James Bay and eastern North America. /Transactions of the 44th North American Wildlife and Natural Resources Conference, Wildlife Management Institute, /Washington, D.C., pp. 498-507.
Morrison, R.I.G., C. Downes, and B. Collins. In press. Population trends of shorebirds on fall migration in eastern Canada, /1974-1991. Wilson Bulletin 106.
Myers, J.P., R.I.G. Morrison, P.Z. Antas, B.A. Harrington, T.E. Lovejoy, M. Sallaberry, S.E. Senner, and A. Tarak. 1987. /Conservation strategy for migratory species. American Scientist 75:19-26.
Page, G., L.E. Stenzel, W.D. Shuford, and C.R. Bruce. 1991. Distribution and abundance of the snowy plover on its western /North American breeding grounds. Journal of Field Ornithology 62:245-255.
Sauer, J.R., and J.B. Bortner. 1991. Population trends from the American woodcock singing-ground survey, 1970-88. Journal /of Wildlife Management 55:300-312.
Schneider, D.C., and B.A. Harrington. 1981. Timing of shorebird migration in relation to prey depletion. Auk 98:197-220.
Senner, S.E., and M.A. Howe. 1984. Conservation of Nearctic shorebirds. Pages 379-421 in J. Burger and B. Olla, editors. /Shorebirds: breeding behavior and populations. Plenum Press, NY.
The International Shorebird Survey is operated by Manomet Observatory for Conservation Sciences. For More information write PO Box 1770, Manomet, MA USA 02345
The following may interest some of our cooperators:
WSG members are sometimes invited to participate in work expeditions of the Australian Wader Study Group at migration staging areas on the NW Australian coast. Work includes banding, censusing, and camp maintenance. Costs, apart from travel to Broome, are moderate. There are daily flights to Broome from Perth and Darwin. For further information write to: Clive Minton, 165 Dalgetty Rd., Beaumaris, Melbourne, VIC 3193, Australia. For information about membership in the Wader Study Group, contact Rodney B. West, Farnham Barn, Farnham, Saxmundham, Suffolk, U.K. The bulletin published by WSG is a wonderful source of information about shorebirds and shorebird projects around the world.
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