Food Habits

Detailed reviews of historical information (Lewis 1993, Mirarchi 1993a) are summarized here.

Feeding

Main Foods Taken

Granivorous habitat generalist that opportunistically takes advantage of seasonally available food resources among a wide variety of habitats that vary across its extensive range. Diet consists mostly (99%) of seeds from cultivated or wild plants with insignificant amounts of animal matter and leafy vegetation incidentally ingested (Mirarchi 1993a).

Microhabitat For Foraging

Feeds almost entirely on ground. Avoids rank, tall vegetation. Seldom feeds where ground litter makes food difficult to find. Will use elevated bird feeders, but usually feeds below on seed scattered on relatively bare ground.

Food Procurement And Consumption

Does not scratch with feet or probe with bill but will move sparse ground litter with whisks of bill to uncover food. Occasionally perches on stiff erect plants while feeding on seed heads [e.g., sunflowers (Helianthus spp.)]. Feeds quickly to fill crop and digests food later at loafing or roosting sites. Usually forages in pairs during nesting season and in large flocks during late summer through autumn.

Diet

Major Food Items

Agricultural crops when available, otherwise seeds of herbaceous plants found in early successional habitats. Documented agricultural crops used include sunflowers (Helianthus spp.), corn (Zea mays), wheat (Triticum aestivum), grain sorghum (Sorghum vulgare), various millets (Panicum spp.), buckwheat (Fagopyrum sagittatum), barley (Hordeum vulgare), and peanuts (Arachis hypogaea).

Nonagricultural seeds used include variety of grasses (e.g., Poa, Paspalum, Setaria, Brachiara), spurges (e.g., crotons [Croton spp.]), goosefoots (e.g., lambsquarter [Chenopodium album] and saltbushes [Atriplex spp.]), composites (e.g., wild sunflowers [Helianthus spp.] and ragweeds [Ambrosia spp.]), pokeweed (Phytolacca americana), poppies (e.g., pricklypoppies [Argemone spp.]), amaranths (e.g., pigweeds [Amaranthus spp.]), smartweeds (Polygonum spp.), hemp (Cannabis sativa), purslanes (e.g., mustards [Brassica spp.]), and pines (Pinus spp.).

Captive mourning doves foraged selectively on white proso millet, dove proso millet, and browntop millet, and generally preferred cultivated crop seeds to non-agricultural seeds; food preferences did not vary seasonally (LeBlanc and Otis 1998; Hayslette and Mirarchi 2001). Animal matter ingested = primarily snails. Grit is essential component of diet, but function is uncertain. Hayslette and Mirarchi (2002), however, suggested that grit may provide an important source of calcium.

Quantitative Analysis

Amount and type of food consumed varies because species is a granivorous habitat generalist that opportunistically takes advantage of seasonally available food resources across its extensive range (see Lewis 1993 for detailed summaries).

Food Selection And Storage

Bilobed crop used for food storage (Mirarchi 1993c), with highest number of seeds in a Mourning Dove crop reported to be 17,200 of annual bluegrass (Poa annua; Rosene 1939). Some evidence suggests food is selected based on taste (Davison and Sullivan 1963); other information suggests visual cues also play a significant role (Goforth and Baskett 1971a). Other results indicate that seed physical characteristics, secondary compound levels, and metabolic efficiencies may influence food selection (Hayslette and Mirarchi 2001).

Nutrition And Energetics

Nutritional requirements and metabolic efficiency not well known. Average daily foods intake about 16% of body mass; 12% in spring and summer and 20% in Sep and Oct (Taber 1928). Average energy intake in Aug and Sep in N. Dakota: 71 kcal/bird (range 67–75; Schmid 1965). Of 9 common food plants tested, common flax (Linum usitatissimum) and charlock (Brassica kaber) had highest energy content; wheat and corn had lowest. Food selection was positively related to nitrogen-free extract (NFE) and negatively related to cellulose-lignin (C–L) levels (Hayslette and Mirarchi 2001). Energy of 12 plant foods used or potentially available during winter in Kansas was evaluated under simulated winter conditions (5°C and 50% relative humidity); 8 diets had acceptable metabolic efficiencies of 69–94% (Shuman et al. 1988). Mourning Doves ingested 7–17 g/d of suitable diets and gained mass on diets of reed canarygrass (Panicum arundinacea), dove proso millet (Panicum miliaceum), grain sorghum, and thistle (Cirsium spp.) but lost mass on diets of corn, Maximilian sunflower (Helianthus maximilianii), common timothy (Phleum pratense), and wheat. Regional mass and fat deposits varied with differences in types of foods eaten and their nutritional value, soil fertility, and farming practices. In another study, greater fat deposits were associated with fertile soils and availability of corn, lower fat deposits with infertile soils and noxious weeds (Hanson and Kossack 1957a). Captive mourning doves will consume salt during nesting, apparently in response to physiological demand for sodium; however, salt did not attract wild doves due to physiological sodium-conserving mechanisms or availability of naturally occurring sodium sources (Hayslette and Mirarchi 2002).

Metabolism And Temperature Regulation

Detailed review in Mirarchi (1993a), briefly summarized here. Natural incubation temperature about 37°C. Rectal body temperatures of nestlings 34.4–42.2°C; varies with age, time of day, and physical activity (Gardner 1930). Homeothermy still incomplete at 12 d; complete homeothermy attained just before fledging at 15 d (Breitenbach and Baskett 1967). Immature birds tend to have higher metabolic rates than adults, and immature females tend to have higher rates than immature males (Ivacic and Labisky 1973). Metabolic expenditures are due more to changing ambient temperature than to changing light:dark ratios. Does not show usual straight-line dependency between metabolic rates and decreasing ambient temperatures. Appears to reduce metabolic rate, body temperature, and heart rates when subjected to decreasing ambient temperatures below critical temperature of 30°C, i.e., becomes torpid when subjected to decreasing ambient temperatures and food restrictions. Uses panting and gular flutter to help regulate hyperthermia (Bartholomew et al. 1968). Augmented cutaneous evaporation is used as primary heat defense; 15–49% of metabolic heat in resting birds dissipated in this manner (Webster and Bernstein 1987). Such evaporation is due to temperature-dependent reductions in skin resistance to water loss; highest losses occur from dorsum.

Drinking, Pellet-Casting And Defecation

Drinking

By suction, without need to lift and tilt head. Requires surface water on regular basis; usually flies to favored drinking spots in morning and evening after feeding (Slade 1969). Appears to prefer unvegetated or lightly vegetated spots with good visibility (e.g., and bars, gravel bars, mudflats) that allow birds to walk to source and avoid ground predators (Lewis 1993).

Minimum water ration required to maintain body mass is 3% of body mass/d (MacMillen 1962). Needs to visit water only a few minutes every day or so to maintain or regain positive water balance.

Although Mourning Doves lose mass if they drink saltwater more concentrated than 0.19 molar, and do not use sea water or strongly saline spring water, they will use saline sources (up to 0.15 molar saltwater) that allow them to maintain a positive water balance. This permits use of many saline desert springs (Bartholomew and MacMillen 1960).

Pellet-Casting

None.

Defecation

Little information reported. Droppings tend to be small and dry when feeding primarily on seeds; when placed on pelleted rations in captivity, however, droppings are much wetter and more voluminous (REM). Captive doves defecated approximately hourly when acclimated to a mixed ad libitum diet of sorghum grains, wheat, cracked corn, and sunflower seeds (JHS).