Demography and Populations

Age At First Breeding; Intervals Between Breeding

Unknown. Presumed to skip first breeding season, then to breed annually as do Common Greenshanks (Cramp and Simmons 1983), but no data.

Clutch

See Breeding: phenology, and Breeding: eggs, above.

Annual And Lifetime Reproductive Success

No information.

Number Of Broods Normally Reared Per Season

See Breeding: phenology, above.

Unknown.

Diseases

Both avian botulism (Clostridium botulinum) and avian cholera (Pasteurella multocida) detected (Sanderson 1962, National Wildlife Health Center unpubl.).

Body Parasites

Reviewed by Secord and Canaris (1993); percentages indicate percentage of host individuals infested.

One bird from Bristol Bay, AK, contained the cestodes Anomotaenia microrhyncha and Schistocephalus solidus (Schmidt and Neiland 1968). Birds from Texas and New Mexico (n = 48) contained A. microrhyncha (52%), A. arionis (46%), Aploparksis filum (27%), and Kowalewskiella totani (8%); A. arionis were significantly more prevalent in females (Secord and Canaris 1993). In Venezuela, cestodes were found in 63.8% of adults and 6.6% of juveniles, gen-erally in low numbers (McNeil et al. 1995).

Taft (1971) reported Cyclocoelum brasilianum in abdominal sacs of 8 of 24 birds from Wisconsin and Iowa. Secord and Canaris (1993; n = 48) found Tanaisia fedtschkoi (19%), Cyclocoelum brasilianum (17%), Stephanoprora paradenticulata (6%), Himasthla alincia (2%), and Plagiorchis muris (2%). Birds from Venezuela (n = 99) contained: in intestines— Mesorchis denticulatus (19.2%), Stictodora sp. (6.1%), Odhneria sp. (5.1%), Maritrema sp. (2.0%), Diplostomum sp. (1.0%); in air sacs and body cavity— Harrahium halli (29.3%), Uvitellina kerii (3.0%); in kidneys— Tanaisia fedtschenkoi (10.1%); in bursa of Fabricius— Prosthogonimus ovatus (9.1%); in cloaca— Parorchis acanthus (3.0%); and in eyes— Philophthalmus nocturnus (1.0%; McNeil et al. 1995). Of these birds, 57.6% were infected by up to 4 trematode species. Of 14 trematode genera, 10 occurred in juveniles and 5 in adults. On arrival in South America, adults more likely to be infested and had significantly more trematodes than juveniles had. Prevalence increased through winter as juveniles became infested; by spring, juveniles had more parasites than adults had. Pathogenic effects of infestations unknown, though may be responsible for oversummering in Tropics (McNeil et al. 1995, 1996). Other species in review by Secord and Canaris (1993): Apharyngostrigea papillistomum, Caiquiria anterouteria, Haematotrephus brasilianum, Tanaisia dubia .

Ancyranthpsis quadripartita reported from Antigua (Clapham 1945), but this genus not found in birds surveyed by Wong and Anderson (1990). Sciadiocara umbellifera reported from Brazil (Cram 1927).

Quadraceps austini (Malcomson 1960), Q. similis (50%), Austromenopon sp. (35%), and Actornithophilus paludosus (19%) (n = 48; Secord and Canaris 1993).

Avenzoaria tringa (50%), Neoboydaia philomachi (8%), Sternostoma boydi (4%), and Rhinonyssus coniventris (2%) (n = 48; Secord and Canaris 1993).

Little information. Sources of adult mortality on breeding grounds (Alaska) include freezing or starving during unusually late bouts of freezing temperatures (B. McCaffery pers. comm.), and predation at nest (TLT, CSE). See also Behavior: predation, above.

Initial Dispersal From Natal Site

No information.

Fidelity To Breeding Site And Winter Home Range

Few data. Three birds banded while breeding returned to breed within a few kilometers the following year (TLT).

Dispersal From Breeding Site

No information.

Home Range

Breeding birds will forage at sites that are disjunct and up to 13 km from nesting sites (TLT). In s.-central Alaska, a brood in an extensive spruce bog stayed within a 110-ha area, and a brood in a small, isolated bog stayed within a 4-ha area (TLT).

Numbers

Population tentatively estimated as 20,000 (Morrison et al. 1994), but this is certainly low. At Big Quill Lake, Saskatchewan, in Jul 1986, 8,600 counted (Gollop 1986). Regional winter estimates: 2,700 in s.-central Louisiana rice fields (Feb; Remsen et al. 1991); 12,300 (95% confidence interval: 3,000–21,600) in California rice fields (Nov–Mar; CSE); 800 along Pacific Coast of U.S. (Nov–Jan; G. Page unpubl. data); 7,800 ± 2,200 SE in coastal Texas (Jan; G. T. Muehl, J. T. Anderson, and T. C. Tacha unpubl.); 2,200 in w. Baja California, Mexico (Jan–Feb; Page et al. in press); 50,000–100,000 on Suriname coast (Spaans 1978); this last estimate seems high, given that Morrison and Ross (1989) counted only 66,000 yellowlegs (both species) and that Lessers generally are far more numerous than Greaters. Note that numbers based on extrapolation generally lack estimates of precision, and absolute counts (usually by aerial survey) are difficult for this sparsely distributed species.

Breeding density estimated as 1–10 pairs (occasionally much greater) in most 10-km squares where recorded in Ontario (Cadman et al. 1987). Francis and Lumbis (1980) estimated the following densities (pairs/km²) for 4 plots in different habitats in ne. Alberta: sedge fen, 11; bitumont muskeg, 3; young black spruce, 1; and tamarack muskeg, 1. One pair nested in a 125-ha spruce bog in Anchorage, AK, along with 3–4 pairs of Lesser Yellowlegs.

Trends

Numbers apparently increased after hunting ceased early in twentieth century (Stone 1937, T. Randall in Bannerman 1961). Between 1966 and 1993, increased by 31.9% on Breeding Bird Survey routes in North America, although during last 10 yr of this period numbers declined by 17% (Price et al. 1995). Neither trend was statistically significant. These data should be viewed with extreme caution, since sample sizes and abundances are extremely low. Data from Christmas Bird Counts (Sauer et al. 1996) indicate significant increases in abundance at northern limits of winter range on both Atlantic (New Jersey, New York) and Pacific (California, Washington) Coasts. This increase may be due to increased search effort, although Greater Yellowlegs are fairly conspicuous.

No information. Without basic demographic information, even speculation is questionable. The fact that habitat losses are greater on wintering grounds than in breeding habitats, however, suggests that global population currently is likely to be limited by nonbreeding conditions.