Diet and Foraging

Main Foods Taken

Wide variety of seeds, berries, and insects.

Microhabitat For Foraging

Among weeds and grasses on the ground, along branches and twigs, occasionally take insects from the air (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close , CTN). In settled areas, forages at feeding stations, either on the ground or on platform feeders.

Food Capture And Consumption

During winter, individuals forage by scratching feet among dried grasses and hopping up at bent-over weeds. Over snow, known to beat weeds with wings and then fly to snow surface to retrieve seeds (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close , Goldman 1976 Goldman, P. (1976). An unusual foraging behavior of Tree Sparrows. Auk 93:644. Close ). Take berries and catkins directly from trees and bushes, up to 15 m above ground (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ); occasionally uses sally maneuvers to capture aerial insects (Shane and Shane 2003 Shane, T. G. and S. J. Shane. (2003). Wintering American Tree Sparrows fly-catching. Kansas Ornithological Society Bulletin 54 (4):45-46. Close ). At feeding stations, consumes seeds from the ground or from feeders.

In summer, take seeds from ground; also glean insects, seeds, and berries from weeds and bushes. Occasionally dart into the air to capture moths or mosquitos (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ).

No definite daily cycles in feeding (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ). At feeding stations, millet preferred over sunflower seeds, corn, bread, and suet (Capainola 1984 Capainola, P. (1984). Feeding strategies among sympatric passerines in winter. Kingbird 34:87-89. Close ). In laboratory experiments, prefer short and thin sunflower seeds (< 12 mm x 4.7 mm) to those of larger dimensions (Willson 1972 Willson, M. F. (1972). Seed size preference in finches. Wilson Bulletin 84: 449–455. Close ). Gaines 1989 Gaines, S. (1989). Comparisons of patch-use models for wintering American Tree Sparrows. Auk 106:118-123. Close discusses the applicability of various feeding patch use models to wintering Tree Sparrows.

Major Food Items

During winter, seeds of Amaranthus retroflexus (pigweed), Ambrosia artemisiifolia (ragweed), Andropogon virginicus (beard grass), Aristida dichotoma (poverty grass), Nepeta cataria (catnip), Chenopodium album (lamb's quarters), Digitarium sanguinale (crab grass), Eleusine indica (yard grass), Elymus virginicus (Virginia wild rye), Festuca pratensis (meadow fescue), Monarda fistulosa (wild bergamot), Panicum sp. (panic grass), Phleum pratense (timothy), Phragmites communis (common reed), Poa compressa (wire grass), P. pratensis (June grass), Polygonum aviculare (knotweed), P. convolvulus (bind weed), P. lapathifolium (smartweed), Setaria glauca (pigeon grass), S. viridis (bottle grass), the goldenrods Solidago altissima, S. nemoralis and S. flexicaulis, and Sporobolus neglectus (sheathed rush grass) have been recorded in the diet (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close , Russak 1956 Russak, M. L. (1956). Tree Sparrows (Spizella arborea) feeding on the common reed. Auk 73:288. Close , Martin 1968 Martin, E. W. (1968). The effects of dietary protein on the energy and nitrogen balance of the Tree Sparrow (Spizella arborea arborea). Physiological Zoology 41:313-331. Close , Goldman 1976 Goldman, P. (1976). An unusual foraging behavior of Tree Sparrows. Auk 93:644. Close , Dance 1986 Dance, K. W. (1986). Winter foods of Northern Cardinal, American Tree Sparrow and Pine Grosbeak in Southern Ontario. Ontario Birds 4:33-35. Close ). For a list of less commonly consumed plant foods, see Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close .

During winter, animal food items include adults and larvae of Coleoptera, pupae of Diptera, adults of Heteroptera, adults of Hymenoptera, eggs and adults of Orthoptera, and Lepidoptera (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ). For a more complete list see Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close .

In summer months, plant foods include Alnus sp. (Alder), Amaranthus sp. (pigweed), Brassica sp. (mustard), Carex sp. (sedge), Draba sp. (alpine whitlow-grass), Empetrum nigrum (crow berry), Eriophoreum sp. (cotton grass), Luzula sp. (northern wood-rush), Myrica gale (sweet gale), Picea spp. (spruce), Poa sp. (bluegrass), Polygonum viviparum (alpine bistort), Potentilla sp. (cinquefoil), Rosaceae leaves, Rubus chamaemorus (cloudberry), Scirpus spp. (bulrush), and Vaccinium spp. (blueberries and cranberries) (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close , West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ).

In summer, insect foods include adults and larvae of Coleoptera, adults and pupae of Diptera, Homoptera, adults and pupae of Hymenoptera, and adults and larvae of Lepidoptera. Non-insect animal foods include Arachnida, Acarina, Araneida and Mollusca (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close , West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close , Baumgartner 1968b Baumgartner, A. M. (1968b). "Tree Sparrow." In Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows and allies., edited by Jr O. L. Austin, 1137-1165. U.S. Natl. Mus. Bull. 237. Close ). For a more complete list, see Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close .

Quantitative Analysis

Proportion of animal matter (dry weight in stomach) in diet is close to 0% from September to April, then increases to near 100% in June and July, falling again by September (West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ). Plant matter in the winter diet was about 50% grass seeds, 40% weed seeds, and 10% other plants (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ). At Churchill, Manitoba, several abundant plants seldom taken as food, e.g., Carex sp., Empetrum nigrum, Myrica gale, Picea spp., Rubus chamaemorus and berries of Vaccinium spp.; other species taken either in proportion to their availability (Amaranthus sp., Brassica sp., one Carex sp., and one Scirpus sp.), or in greater proportion to their availability (Carex spp., Draba sp., Eriophorum sp., and seeds of Vaccinium spp.) (West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ).

Average energy value of summer diet at Churchill, Manitoba, calculated to be 5,211 cal/g (West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ). Each bird requires 20–25 kcal/d (= 5.1 to 6.3 g/d of food, or about 30% of adult body weight), with a mean minimum in captive birds of 17.84 kcal/d (West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ). The fasting endurance of American Tree Sparrows in winter was 30 h (range 21–40 h; n = 10); the mean weight loss of these birds was 18% (range 14–24%) (Stuebe and Ketterson 1982 Stuebe, M. M. and E. D. Ketterson. (1982). A study of fasting in Tree Sparrows (Spizella arborea) and Dark-eyed Juncos (Junco hyemalis): ecological implications. Auk 99:299-308. Close ). American Tree Sparrows fit model examining cost of amount of fat deposit with habitat type and exposure to predation (Rogers 2015 Rogers, C. M. (2015). Testing optimal body mass theory: Evidence for cost of fat in wintering birds. Ecosphere 6 (4):55. Close ).

On a diet of ground seeds in summer, the digestion efficiency of American Tree Sparrows was 75.8% (West 1973 West, G. C. (1973). Foods eaten by Tree Sparrows in relation to availability during summer in northern Manitoba. Arctic 26:7-21. Close ); during winter, digestion efficiency was 85.4% (diet of sunflower, millet or sorghum; Shuman et al. 1989 Shuman, T. W., R. J. Robel, J. L. Zimmerman, and K. E. Kemp (1989). Variance in digestive efficiencies of four sympatric avian granivores. Auk 106: 324–326. Close ). In captive birds, gross energy intake decreased with increasing temperature and was described by the equation 25.89 kcal/bird/d – 0.254 x °C. Energy lost in excrement decreased with increasing temperature (= 6.84 kcal/bird/d – 0.088 x °C). Metabolized energy decreased with increasing temperature (19.05 kcal/bird/d – 0.167 x °C; West 1960 West, G. C. (1960). Seasonal variation in the energy balance of the Tree Sparrow in relation to migration. Auk 77:306-329. Close ). Body temperature was lower in individuals deprived of food (Stuebe and Ketterson 1982 Stuebe, M. M. and E. D. Ketterson. (1982). A study of fasting in Tree Sparrows (Spizella arborea) and Dark-eyed Juncos (Junco hyemalis): ecological implications. Auk 99:299-308. Close ). Measured plasma glycerol and triglyceride levels and creatine kinase activity of overwintering birds in South Dakota suggested that American Tree Sparrows have the ability to rapidly replace fat stores (Swanson and Thomas 2007 Swanson, D. L. and N. E. Thomas. (2007). The relationship of plasma indicators of lipid metabolism and muscle damage to overnight temperature in winter-acclimatized small birds. Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology 146 (1):87-94. Close ).

On average, captive individuals drink 29.6% of their body weight in water/d, with a minimum intake of 15%/d (Ohmart and Smith 1970 Ohmart, R. D. and E. L. Smith. (1970). Use of sodium chloride solutions by the Brewer's Sparrow and Tree Sparrow. Auk 87:329-341. Close ). During winter months, snow may be eaten in to obtain water (Baumgartner 1968b Baumgartner, A. M. (1968b). "Tree Sparrow." In Life histories of North American cardinals, grosbeaks, buntings, towhees, finches, sparrows and allies., edited by Jr O. L. Austin, 1137-1165. U.S. Natl. Mus. Bull. 237. Close ). Usually defecate once every half hour, each excreta weighs 0.5–0.6 g (Baumgartner 1937b Baumgartner, A. M. (1937b). Food and feeding habits of the Tree Sparrow. Wilson Bulletin 49:65-80. Close ).