Food Use by Migratory Female Mallards in Northwest Missouri

Gruenhagen, Ned M.; Fredrickson, Leigh H.

doi:10.2307/3809359

Cited by 16 publications

(11 citation statements)

References 17 publications

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“…Seeds differ greatly in their nutritional value, particularly related to energy content (Checkett et al 2002), which could lead to selection or avoidance of some plant communities by waterfowl. Although diet studies suggest waterfowl use foods proportional to their availability at specific foraging sites (Miller 1986, Euliss and Harris 1987, Gruenhagen and Fredrickson 1990, Combs and Fredrickson 1996, decisions about site selection may be influenced by cues that include plant species composition (Cody 1985). Our analysis using only seeds of barnyard grass (species frequently consumed by waterfowl that has relatively high energy content [Checkett et al 2002] and comprised 52% and 66% of total seed biomass in year 1 and 2, respectively) were similar to results for all seeds, suggesting plant community composition was not an important factor influencing seed loss.…”

Section: Discussionmentioning

confidence: 99%

“…Although we did not determine the proportion of seed loss directly attributable to waterfowl consumption, the dense concentration of waterfowl in study impoundments strongly implies seed depredation by waterfowl. Waterfowl in fallflooded impoundments were likely attracted to the high numbers of desirable seeds (95% of seed species frequently eaten by waterfowl [Bellrose and Anderson 1943, Korschgen 1955, Gruenhagen and Fredrickson 1990), protection from disturbance and optimal foraging depths. Protection from hunting was probably not the reason for high seed loss however, as the single fall-flooded impoundment open to hunting (FGCA, year 2) experienced high depletion (92%) and birds will forage at night.…”

Section: Discussionmentioning

confidence: 99%

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The Effects of Seasonal Flooding on Seed Availability for Spring Migrating Waterfowl

et al. 2007

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We hypothesized the seed biomass available to migrating waterfowl would be higher in spring‐ versus fall‐flooded wetlands. To test this hypothesis we conducted an experiment using 5 pairs of wetland impoundments in northern Missouri, USA (2000‐2002). We strategically assigned one impoundment of each pair to either a fall or spring treatment group. We estimated seed biomass in fall and in spring by clipping seed heads and collecting soil cores at 20 random locations within each impoundment. We placed exclosures near each fall sample site in spring‐flooded impoundments to estimate seed loss from granivorous birds and rodents. Despite similar biomass in fall between treatments (P = 0.64), overwinter seed loss was greater in fall‐flooded (79%; 1,324 ± 195 kg/ha) than in spring‐flooded (31%; 653 6 130 kg/ha) impoundments (P = 0.009). Considering barnyard grass or millet (Echinochloa spp.) only, seed loss was higher in fall‐flooded than in spring‐flooded impoundments (P = 0.05). Spring biomass estimates were similar inside versus outside exclosures (P = 0.63) indicating loss to granivorous birds and rodents was limited. Our results suggest that fall flooding reduces seed availability for spring migrating waterfowl. We recommend spring flooding be used in areas where impoundment water levels can be manipulated to increase seed availability for spring migrating waterfowl.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The Effects of Seasonal Flooding on Seed Availability for Spring Migrating Waterfowl

et al. 2007

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“…Aquatic snails are part of the regular diet of mallards (Swanson et al 1985; Gruenhagen and Fredrickson 1990; Baldwin and Lovvorn 1994; Rodrigues et al 2002), and Hydrobia ( P. ) ulvae is a common marine snail with an operculum, of which a small percentage can survive passage through duck guts (Anders et al 2009; Cadée 2011; Van Leeuwen et al 2012). This species also occurs in brackish environments, and is not affected by short-term exposure to freshwater (Fenchel 1975).…”

Section: Methodsmentioning

confidence: 99%

Vector activity and propagule size affect dispersal potential by vertebrates

2012

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Many small organisms in various life stages can be transported in the digestive system of larger vertebrates, a process known as endozoochory. Potential dispersal distances of these “propagules” are generally calculated after monitoring retrieval in experiments with resting vector animals. We argue that vectors in natural situations will be actively moving during effective transport rather than resting. We here test for the first time how physical activity of a vector animal might affect its dispersal efficiency. We compared digestive characteristics between swimming, wading (i.e. resting in water) and isolation (i.e. resting in a cage) mallards (Anas platyrhynchos). We fed plastic markers and aquatic gastropods, and monitored retrieval and survival of these propagules in the droppings over 24 h. Over a period of 5 h of swimming, mallards excreted 1.5 times more markers than when wading and 2.3 times more markers than isolation birds, the pattern being reversed over the subsequent period of monitoring where all birds were resting. Retention times of markers were shortened for approximately 1 h for swimming, and 0.5 h for wading birds. Shorter retention times imply higher survival of propagules at increased vector activity. However, digestive intensity measured directly by retrieval of snail shells was not a straightforward function of level of activity. Increased marker size had a negative effect on discharge rate. Our experiment indicates that previous estimates of propagule dispersal distances based on resting animals are overestimated, while propagule survival seems underestimated. These findings have implications for the dispersal of invasive species, meta-population structures and long distance colonization events.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-012-2293-0) contains supplementary material, which is available to authorized users.

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“…Gates et al (2001) showed for canada geese B. canadensis interior in Gauthier et al (1984Gauthier et al ( , 1992Gauthier et al ( , 2003, Gauthier and Tardif (1991), Gauthier (1993), Choinie`re and Gauthier (1995), Giroux and Bergeron (1996) Ross's goose Anser rossii McLandress and Raveling (1981a, b), Thomas (1983) Barnacle goose B. leucopsis Ebbinge et al (1982), Teunissen et al (1985), Prop and Deerenberg (1991), Drent (1996), Pettifor et al (2000, Van der Wal et al (2000) Light Dwyer (1975), Paulus (1984), Ringelman (1990), , Jeske (1996) Gruenhagen and Fredrickson (1990), Owen and Black (1990), Jeske (1996), Dugger (1997) American Taylor (1978), DeRoia and Bookhout (1989), Gammonley and Fredrickson (1995), …”

Section: Foraging and Dietmentioning

confidence: 96%

Ecology of spring-migrating Anatidae: a review

2006

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Spring migration is generally considered as a crucial period of the year for many birds, not the least due to its supposed importance for subsequent breeding success. By reviewing the existing literature for Anatidae (ducks, geese, and swans), we show that little is known about their ecology in spring, although some goose species are exceptions. Another general pattern is that the ecology of Anatidae at staging sites is particularly neglected. Existing studies tend to focus on questions dealing with acquisition of nutrient reserves, whereas almost nothing has been published about stopover habitats, time use, microhabitat use, foraging behaviour, food availability, food limitation, diet selection, and interspecific relationships. Besides summarising present knowledge, we identify taxonomic groups and topics for which gaps of knowledge appear the most evident, thereby also highlighting research needs for the future.

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Food Use by Migratory Female Mallards in Northwest Missouri

Cited by 16 publications

References 17 publications

The Effects of Seasonal Flooding on Seed Availability for Spring Migrating Waterfowl

The Effects of Seasonal Flooding on Seed Availability for Spring Migrating Waterfowl

Vector activity and propagule size affect dispersal potential by vertebrates

Ecology of spring-migrating Anatidae: a review

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