Food Habits

Main Foods Taken

Crustaceans, particularly fiddler crabs; some insects (Strauch and Abele 1979, Morrier and McNeil 1991, Thibault and McNeil 1994, 1995).

Microhabitat For Foraging

Intertidal mudflats in Panama, Venezuela, and Georgia (Strauch and Abele 1979, Robert and McNeil 1989, Thibault and McNeil 1994, 1995, CAC). Also in intertidal areas and above high-tide mark on sandy beaches in Georgia (CAC). Bergstrom (1982) observed feeding near nests on sparsely vegetated salt flats in Texas.

Food Capture And Consumption

Usually forages during low tide on intertidal mudflats, but not for entire low-tide period (Strauch and Abele 1979, Thibault and McNeil 1994, 1995). Visual feeder; catches prey with running lunge up to 1 m while in crouched position; extends neck at moment of capture (Strauch and Abele 1979, Thibault and McNeil 1995). Neck may be cocked during run (Bergstrom 1982). Bergstrom observed Wilson’s Plovers holding crabs by a leg and shaking the crab to break off the leg. This was repeated until a legless carapace was swallowed whole; handling time >1 min/crab.

Feeding patterns varied seasonally in resident Venezuela population. Overall percentage of time spent on foraging sites did not vary, but from Nov to Jan daytime foraging decreased and nocturnal foraging increased; fed more in early evening (19:00–22:00). During laying and incubation, males incubated most of the night and females foraged, whereas males and nonbreeders foraged during the day (Thibault and McNeil 1994, 1995).

Individuals observed near nests or young in Texas during daylight incubation, hatching, or attending young chicks spent 1–43% of the time feeding on fiddler crabs (including stalking, chasing, and handling time); number of crabs captured per hour of feeding time ranged from 0 to 43 (Bergstrom 1982).

Crustaceans, particularly fiddler crabs, are the most important food in Texas, Panama, and Venezuela, constituting up to 98% of diet in Venezuela (Strauch and Abele 1979, Bergstrom 1982, Thibault and McNeil 1994, 1995). Stomach contents (hard parts only) of 26 Wilson’s Plovers collected during Oct and Nov in w. Panama were examined (Strauch and Abele 1979). Analysis revealed no dietary differences between sexes or months. Diet was made up (by frequency of occurrence of 188 items) of 95.7% crustaceans, 1.1% annelids, and 3.8% insects. Mean prey size estimated at 7.8 mm (range 0.5–11). On the basis of observations of feeding Wilson’s Plovers in Venezuela, Morrier and McNeil (1991) reported a diet of 98.6% fiddler crabs. Prey size was estimated by comparison of carapace width to plover bill length. Wilson’s Plovers ate mostly crabs with carapace width equal to one-fourth (41.5% of total crabs eaten, n = 275) or one-half (38.6%) of their bill length. Average bill length of plovers in that study was 20.5 mm (n = 141).

See Feeding, above.

Estimated diurnal energy expenditure for individuals in Venezuela during nonbreeding season ranged from 42.6 to 50.2 kJ, with highest expenditures at beginning of Apr and end of Oct (Morrier and McNeil 1991). Estimates of total diurnal energy intake per individual ranged from 0.04 to 99.06 kJ. Diurnal energy intake was insufficient to account for diurnal energy expenditure from Nov through Mar, leading the authors to assume that feeding occurred at night.

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