Diet and Foraging

Main Foods Taken

Mainly invertebrates and plant material. On migration, may rely heavily on plant tubers at inland sites (Alexander et al. 1996 Alexander, S. A., K. A. Hobson, C. L. Gratto-Trevor and A. W. Diamond. (1996). Conventional and isotopic determination of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers. Canadian Journal of Zoology 74:1057-1068. Close ).

Microhabitat For Foraging

Few quantitative data. On breeding grounds, feeds mainly in wet parts of sedge marsh and along vegetated edges of shallow tundra pools; pairs nesting near coast and premigratory flocks feed on exposed mud on tidal flats (Hagar 1966 Hagar, J. A. (1966). Nesting of the Hudsonian Godwit at Churchill, Manitoba. Living Bird 5:5-43. Close , CSE). In Churchill area, often feeds in same places as Stilt Sandpipers, Short-billed Dowitchers, and Lesser Yellowlegs (Tringa flavipes). During fall migration at Quill Lakes, SK, typically seen feeding in flooded areas; slightly >50% of time spent in water shallower than length of the birds' tarsi, the rest of the time in deeper water; not seen feeding in areas that were dry or merely covered with a film of water (Alexander and Gratto-Trevor 1997 Alexander, S. A., and C. Gratto-Trevor (1997). Shorebird migration and staging at a large prairie lake and wetland complex: The Quill Lakes, Saskatchewan. Canadian Wildlife Service Occasional Papers no. 97. Environment Canada, Ottawa, Ontario, Canada. Close ). In spring, at Cheyenne Bottoms, KS, 82% of 244 birds found in open shallow water, 17% at water-mud interface; mean water depth for 235 foraging birds was 5.1 cm ± 3.1 SD; generally avoided vegetation (Helmers 1991 Helmers, D. L. (1991). Habitat use by migrant shorebirds and invertebrate availability in a managed wetland complex. Unpubl. Master's Thesis, Univ. of Missouri, Columbia. Close ). At Lagoa do Peixe, Brazil, higher numbers found in flooded areas at least several centimeters deep than in areas with exposed mud or wet sand; in this study, occasionally used pools in sand dunes for roosting but never fed on the beach (Lara Resende and Leeuwenberg 1987 Lara Resende, S. de M. and F. Leeuwenberg. (1987). Ecological studies of Lagoa do Peixe. WWF/US. Close , Lara Resende 1988 Lara Resende, S. de M. (1988). Nonbreeding strategies of migratory birds at Lagoa do Peixe, Rio Grande do Sul, Brazil. Master's Thesis, Cornell Univ., Ithaca, NY. Close ).

Food Capture And Consumption

Obtains most food by probing with at least one-quarter of bill inserted into mud, but also by pecks in which just the tip enters mud or prey is plucked from water column, mud surface, or vegetation (Alexander and Gratto-Trevor 1997 Alexander, S. A., and C. Gratto-Trevor (1997). Shorebird migration and staging at a large prairie lake and wetland complex: The Quill Lakes, Saskatchewan. Canadian Wildlife Service Occasional Papers no. 97. Environment Canada, Ottawa, Ontario, Canada. Close , JK). Often inserts bill deep into mud and submerges head when feeding in water; may probe rapidly like a dowitcher (Wright 1987 Wright, G. (1987). Hudsonian Godwit in Devon. British Birds 80:492-494. Close ). Captured prey items pass along bill rapidly (Wetmore 1926c Wetmore, A. (1926). Observations on the birds of Argentina, Paraguay, Uruguay, and Chile. United States National Museum Bulletin 133:1–448. Close ). Adults guarding small chicks glean insects from vegetation.

On vegetated pond margins, walks slowly in water up to belly, dips whole head in water, in monotonous motion: step-dip, step-dip; may make multiple dips from one place. Feeding birds stop periodically to preen or to look around; also when other shorebirds call. Will wade or swim through deep water. On muddy substrates, tilts whole body forward to probe, often close to base of vegetation or partially submerged rocks if present. Often runs between making pecks on mudflats, suggesting use of visual cues more than when feeding underwater. When feeding on tubers, has a distinctive manner of pushing bill into mud and rotating it to make a small hole by the plant. Often makes several probes in quick succession (Alexander 1994 Alexander, S. A. (1994). Inland staging by shorebirds during autumn migration: diet, prey availability, body composition, and flight range. Master's Thesis, Univ. of Saskatchewan, Saskatoon, SK. Close , Alexander et al. 1996 Alexander, S. A., K. A. Hobson, C. L. Gratto-Trevor and A. W. Diamond. (1996). Conventional and isotopic determination of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers. Canadian Journal of Zoology 74:1057-1068. Close ).

Presumably locates food by touch while probing, by sight when gleaning. Bill tip reportedly “flexible” (L. C. Sanford in Bent 1927 Bent, A. C. (1927). Life histories of North American shorebirds, Part 1. U.S. Nat. Mus. Bull. 142. Close ) implying at least 1 rhynchokinetic joint that may help individuals grasp food items buried deep in mud.

Few data on feeding performance, but success rates of 48–71% recorded for 4 birds feeding in Carex marsh at Susitna Flats, AK (L. Tibbitts unpubl.), while success rates of 0-13% (n = 217) were recorded at wintering sites across southern South America (Senner and Senner unpubl.). One bird in Britain ate 40–50 prey items/min (Grieve 1987 Grieve, A. (1987). Hudsonian Godwit: new to the Western Palearctic. British Birds 80:466-473. Close ).

Few data. One study on breeding grounds at Churchill (n = 12 birds; Baker 1977c Baker, M. C. (1977c). Shorebird food habits in the eastern Canadian Arctic. Condor 79:56–62. Close ) found majority of stomach contents to consist of insect larvae (Diptera: Cyclorrapha and Tipulidae) and beetles (Coleoptera: adult and larval Chrysomelidae, Donacia, and adult Dysticidae Hygrotus); >50% of food items were Cyclorrapha larvae, with <10% each of Tipulidae larvae, adult Donacia, larval Donacia, adult Hygrotus, unidentified snails (Gastropoda) and seeds. In that study, Hudsonian Godwits tended to select prey approximately 3–6 mm in length (mean length approx. 5 mm), but took items ranging from 2 to >10 mm in length.

Gizzards of 5 birds collected on breeding grounds at Mackenzie River delta, NWT, contained mostly invertebrates (Diptera: Tabanidae larvae, Trichoptera larvae, Hemiptera adults, Hymenoptera adults) and small snails (1–4 mm). Stable isotope analyses of tissue from these birds also suggested that invertebrates were main food source (Alexander et al. 1996 Alexander, S. A., K. A. Hobson, C. L. Gratto-Trevor and A. W. Diamond. (1996). Conventional and isotopic determination of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers. Canadian Journal of Zoology 74:1057-1068. Close ).

During fall migration, tubers of sago pondweed (Potamogeton pectinatus) made up majority of diet at Quill Lakes: 94% of food volume in esophagus and proventriculus (n = 20 birds, 114 food items) and 66% of items in gizzard (n = 17 birds, 402 food items). Analyses of stable isotope ratios suggested that sago pondweed constituted 61–74% of diet at this site. Despite this apparent discrepancy, 95% confidence intervals around this estimate encompassed the estimate based on gut-content analysis. Clearly, plant tubers are a major portion of diet at this staging site; possible that a carbohydrate-rich diet may be especially important for godwits preparing to embark on long migratory flights (Alexander 1994 Alexander, S. A. (1994). Inland staging by shorebirds during autumn migration: diet, prey availability, body composition, and flight range. Master's Thesis, Univ. of Saskatchewan, Saskatoon, SK. Close ). Other food items in esophagus-proventriculus of these birds included: seeds (2% of volume; found in 3 individuals) and Diptera: Chironomidae larvae (4%; 1). And in gizzard, seeds (mostly Potamogeton and Scirpus spp.; 27% of food items; found in 11 individuals), Eleocharis parvula tubers (1%; 1), Diptera: Chironomidae larvae (2%; 2), Coleoptera larvae: Dytiscidae (<1%; 1), Haliplidae (<1%; 1), Hydrophilidae (<1%, 1), Hemiptera: Corixidae (2%; 2), and Orthoptera: Acrididae (2%; 1). Seeds in diet showed no evidence of digestion, suggesting they may have been eaten to help grind other food (Alexander et al. 1996 Alexander, S. A., K. A. Hobson, C. L. Gratto-Trevor and A. W. Diamond. (1996). Conventional and isotopic determination of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers. Canadian Journal of Zoology 74:1057-1068. Close ).

At Samborombón Bay, Argentina, diet primarily nereid worms (Laeonereis acuta and Neanthes succinea); fiddler crabs (Uca uruguayensis) made up 0.6% of food items, but more important in terms of biomass (Ieno 2000 Ieno, E. (2000). Las comunidades bentónicas de fondos blandos del norte de la Provincia de Buenos Aires: Su rol ecológico en el ecosistema costero. Tesis Doctoral, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. Close ). At Punta Loyola, Patagonia, Argentina, bivalve Darina solenoides is eaten (Bala et al. 1998 Bala, L., M. Hernandez and M. C. Baarck. (1998). Análisis de la dieta de Limosa haemastica, en Punta Loyola, Santa Cruz. Reunión Argentina de Ornitología 3. Close ).

Other reports of foods include earthworms (Annelida), insects (horseflies [Tabanidae], mosquitoes [Culicidae]), mollusks (including Macoma balthica), crustaceans (including amphipods), and other small invertebrates (Forbush 1925 Forbush, E. H. (1925). Birds of Massachusetts and other New England states Part 1. Commonwealth of Massachusetts. Massachusetts Dept. Agriculture: Commonwealth of Massachusetts. Close , Martini et al. 1980 Martini, A. C., R. I. G. Morrison, W. A. Glooschenko and R. Protz. (1980). Coastal studies in James Bay, Ontario. Geosci. Canada 7:11-21. Close , Wright 1987 Wright, G. (1987). Hudsonian Godwit in Devon. British Birds 80:492-494. Close ); predominantly polychaete worms on intertidal mudflats of Tierra del Fuego (Piersma et al. 1996c Piersma, T., J. van Gils and P. Wiersma. (1996c). "Family Scolopacidae (sandpipers, snipes and phalaropes)." In Handbook of the birds of the world. Vol. 3. Hoatzin to auks., edited by J. del Hoyo, A. Elliott and J. Sargatal, 444-533. Barcelona, Spain: Lynx Edicions. Close ); crowberries (Empetrum nigrum) on breeding grounds in Alaska (B. McCaffery and C. Harwood pers. comm.).

Little information. Apparently feeds opportunistically. Baker (Baker 1977c Baker, M. C. (1977c). Shorebird food habits in the eastern Canadian Arctic. Condor 79:56–62. Close ) found evidence that individuals select prey on average larger than expected based on size range available; however, prey taken were not the largest available. In Argentina, found to select the largest (40–60 mm) nereid worms (Ieno 2000 Ieno, E. (2000). Las comunidades bentónicas de fondos blandos del norte de la Provincia de Buenos Aires: Su rol ecológico en el ecosistema costero. Tesis Doctoral, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. Close ). Higher incidence of invertebrates in diet during the breeding season than during migration may reflect low availability of tubers on breeding grounds, but also could indicate selection for foods rich in protein and calcium while breeding; high incidence of snails in diet from Mackenzie River delta, in particular, may indicate selection for calcium-rich food (Alexander et al. 1996 Alexander, S. A., K. A. Hobson, C. L. Gratto-Trevor and A. W. Diamond. (1996). Conventional and isotopic determination of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers. Canadian Journal of Zoology 74:1057-1068. Close ).

Caching unknown.

Little information on Hudsonian Godwit; see Migration: control and physiology, above. Larger congener, Bar-tailed Godwit, prior to migration shows body mass increase of 6.0 g/d (Kersten and Piersma 1987 Kersten, M. and T. Piersma. (1987). High levels of energy expenditure in shorebirds; metabolic adaptations to an energetically expensive way of life. Ardea 75:175-187. Close ). Daily energy expenditure of 3.5-d-old Hudsonian Godwit chicks raised in captivity can range from 12.1 to 50.3 kJ/d (with mass of chicks, respectively, 25.2 and 32.7 g), and increases to an average of 297 kJ/d in 17-d-olds (K. Krijgsveld pers. comm.; Williams et al. 2007). Net energy intake in adults of the larger Bar-tailed Godwit estimated as 610–886 kJ/d (Kersten and Piersma 1987 Kersten, M. and T. Piersma. (1987). High levels of energy expenditure in shorebirds; metabolic adaptations to an energetically expensive way of life. Ardea 75:175-187. Close ). Based on field observations, estimated to consume 0.21 mg AFDW (ash-free dry weight)/s, though this estimate may be low (Ieno 2000 Ieno, E. (2000). Las comunidades bentónicas de fondos blandos del norte de la Provincia de Buenos Aires: Su rol ecológico en el ecosistema costero. Tesis Doctoral, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. Close , E. Ieno pers. comm.). Using allometric relationships, mean metabolic rate of adults estimated at 273 kJ/d (Ieno 2000 Ieno, E. (2000). Las comunidades bentónicas de fondos blandos del norte de la Provincia de Buenos Aires: Su rol ecológico en el ecosistema costero. Tesis Doctoral, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. Close ).

No information.

Little information. Pellet-casting not reported, but found in many large shorebirds; incidence may depend on diet. Bends legs at tibiotarsal joint in slight squat while defecating.