Conservation and Management

Shooting, Trapping, And Egging

In the past, market-hunting and egging greatly reduced East Coast populations (see Distribution: historical changes, above). Audubon (1871: 327) wrote that “ . . . eggs afford excellent eating” and that young “. . . grow rapidly, become fat and juicy, and by the time they are able to fly, afford excellent food.”

Pesticides And Other Contaminants/Toxics

Arsenic, selenium, mercury, DDE, and other organochlorines are potential contaminants that are associated with agricultural runoff or historical practices and that accumulate in coastal sediments. All of these contaminants occur at coastal sites in s. Texas, and all found in Willets; only arsenic found at elevated levels (Custer and Mitchell 1991). In S. Carolina, concentrations of organochlorines found in several species of estuarine birds dropped between 1971 and 1975; DDE detected in single adult Willet, but no PCBs found (Blus and Lamont 1979).

Insecticides (e.g., carbaryl, chlorpyrifos, deltamethrin, dimethoate, malathion: primarily for grasshopper control) used in western breeding habitat (D. Forsyth pers. comm., O. Olfert pers. comm.); extent and possible effects on adults or growing young unstudied. Possibly more important indirectly, in decreasing food availability.

Ingestion Of Plastics, Lead, Etc

No information.

Collisions With Stationary/Moving Structure Or Objects

Western Willets occasionally hit by vehicles, especially during brood period. Many leg and wing injuries and deaths at site in s. Alberta presumed due to impact with power lines, common through wetlands there (see Causes of mortality, above). In prairies, power lines often put through wetlands as less expensive than acquiring right-of-way through cultivated land. Smaller power lines often accompany oil and gas activity. Adults probably most at risk during aerial territorial and sexual chases early in season and during brood care. Newly fledged young also vulnerable (CLG-T).

Degradation Of Habitat

Breeding, Western. Worldwide, grasslands most imperiled ecosystem. Huge decrease in historic grasslands in North America: <1% intact in some areas (Sampson and Knopf 1996). Grazing useful in maintaining preferred low vegetation, but overgrazing may be a problem. Conversion of native grassland to agricultural crops disadvantageous (possibly acts as “sink” where birds may try to nest but rarely successfully). Willets generally avoid tall, dense nesting cover planted for waterfowl in prairies. Draining and plowing of temporary and ephemeral wetlands for crops and maintenance of high water levels for tourism and irrigation also are problems. Managed wetlands advantageous if they have shallow water and little vegetation at edges, not steep slopes or cattail (Typha spp.). In wetland complexes, advantageous if variety of water levels present, including very shallow wetlands. Permanent habitat loss when oil and gas pipeline routes, roads, and pump stations replanted in tall, dense, nonnative and invasive grasses. Temporary habitat loss when large areas sprayed with drill mud via largetracked vehicles during breeding season. Center-pivot irrigation allows cultivation of formerly arid lands, and may lower water table, thereby changing surface water and vegetation (Ryan et al. 1984, Senner and Howe 1984, Clary and Medin 1992, Page and Gill 1994, D. Johnson pers. comm., CLG-T).

Breeding, Eastern. Mosquito-ditching results in replacement of natural grass associations with shrubby growths and reduced invertebrate prey of shorebirds (Bourn and Cottam 1950). Draining and impoundment of salt marshes in Maritime Provinces reduced habitat quality in some locales (Erskine 1992).

Migration and Wintering. Many potential coastal staging sites in California lost or degraded due to development (e.g., in San Francisco Bay, tidal mudflat habitat decreased from 20,000 ha in 1800 to about 12,000 ha at present; Goals Project 1999). Un-known effects of changes in benthic invertebrate prey due to introduction of nonnative invertebrates from ship ballast, etc. (G. Page pers. comm.). In Mexico, economic development increasing at important shorebird sites: agriculture, commercial fishing, shrimp aquaculture, tourism (including ecotourism), and hunting (Page et al. 1997, Engilis et al. 1998). Interior-staging Willets depend on shallow-water habitats. Increasing numbers of ephemeral and temporary wetlands converted to agriculture, and water in remaining wetlands often managed at high levels for irrigation and tourism (Skagen and Knopf 1993, CLG-T).

Disturbance At Nest And Roost Sites

In area of intense oil and gas activity in s. Alberta, disturbance itself from heavy machinery and vehicles apparently little or no effect on nesting Willets, and return rates to site in subsequent years normally high. Birds, even in areas of permanent wetlands, nest in low concentrations; in many hours of all terrain–vehicle (ATV) driving in 19-km²area for 6 yr, re-searchers observed no Willet flushed from completed clutch by ATV (CLG-T). Increasing distur-bance of roosting birds by dogs in some areas of Baja California, especially San Quintin Bay (L. Tibbitts pers. comm.) and in s. California (G. Page pers. comm.).

Direct Human/Research Impacts

Auxiliary wing markers (patagial tags of Herculite plastic secured around humerus with small aluminum grommet) greatly affected return rates of Eastern Willets: 0 of 27 (0%) patagial tagged birds returned in subsequent year versus 14 of 22 (64%) untagged but leg-banded; suggestion that tags interfered with transoceanic migratory flight, causing severe mortality in tagged birds (Howe 1980).

Four of 79 (5%) nests abandoned in Prairie Pothole Study where nests monitored but birds not captured (Kantrud and Higgins 1992). In s. Alberta, only 4 known desertions (3 nests with 2 eggs, 1 female with broken wing from power line) of 242 nests (2%), many of which had both parents captured on nest and often blood sampled; no known desertions if birds flushed from incomplete clutches, no effect of capture or blood sampling on return rates in subsequent years. In s. Alberta study, most nests found by chain-drag technique, which occasionally resulted in dented or broken eggs in Marbled Godwits, but not Willets. No known injuries to adults from capture, banding, or blood sampling; broken leg and chest injuries in male possibly from nest-finding, possibly power line; swelling in upper chest of 2 birds possibly from chain drag, both continued to incubate and were unaffected several weeks later. Unclear if flushing birds from nests results in slightly higher egg-predation rates (CLG-T). Nest visits probably increased raccoon predation upon nests at Wallop’s I., VA (Howe 1982). Increased disturbance results in longer observed incubation periods (see Breeding: incubation, above).

Conservation Status

Not listed.

Measures Proposed And Taken

No specific protection in Canada and U.S. other than Migratory Bird Convention Act and Migratory Bird and Game Management Treaty between Mexico and U.S. (1937). Western Hemisphere Shorebird Reserve Network (WHSRN) sites provide some protection by increased awareness of site’s importance. Important shorebird sites in U.S. and Canada (potential WHSRN sites) listing Willets as significant species are: Bolinas Lagoon, Elkhorn Slough, and Morro Bay in California, and Coot Bay-Everglades in Florida (Harrington and Perry 1995, Morrison et al. 1995). San Francisco Bay, CA, most important site in U.S. for nonbreeding Willets (Page et al. 1999).

Management recommendations include: Breeding. Protect contiguous blocks of native grassland >1 km²with diverse complex of wetland types, including temporary ponds; maintain preferred habitat of shorter, sparser vegetation by rotational grazing or temporarily idled grazed grassland (avoid grazing until early to late Jun); bury power lines or do not put lines through wetlands; maintain shallow-water ponds with little or no emergent vegetation for pre- and postbreeding flocks; maintain shallow-water ponds with margins of emergent vegetation for broods; minimize oil and gas activity (especially drill mud–spraying) during May and Jun (Ryan et al. 1984, Colwell and Oring 1988, Kantrud and Higgins 1992, Dechant et al. 1999, CLG-T).

Staging and Wintering. Provide protection from development, degradation, and disturbance to major coastal staging and wintering sites where necessary (Page et al. 1997, Engilis et al. 1998). Provisions specifically to protect shorebird habitats should be included in existing management plans at these sites. Conservation efforts should focus on identifying all staging and wintering sites important to Willets and, if necessary, providing them with some level of protection (e.g., WHSRN site designations, local wildlife reserves). For many of these sites, substantial efforts will be needed to complete and implement comprehensive landuse plans that minimize negative impacts to shorebirds (L. Tibbitts pers. comm.).

Effectiveness Of Measures

Primarily unknown or untested.