Use of Southern Boreal Lakes by Postbreeding Canvasbacks and Redheads

Bergman, Robert D.

doi:10.2307/3798898

Cited by 20 publications

(12 citation statements)

References 6 publications

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“…Various studies have indicated that migratory birds depend on favourable wind patterns to extend their flight range with a given amount of body stores [97][98][99][100][101][102][103]. Some bird species, in fact, are believed to be unable to complete their migratory journey without substantial wind assistance [104].…”

Section: Resource Phenology and Weather Conditions (A) Weather Conditmentioning

confidence: 99%

Ecophysiology of avian migration in the face of current global hazards

Klaassen

Hoye

Nolet

et al. 2012

Phil. Trans. R. Soc. B

114

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Long-distance migratory birds are often considered extreme athletes, possessing a range of traits that approach the physiological limits of vertebrate design. In addition, their movements must be carefully timed to ensure that they obtain resources of sufficient quantity and quality to satisfy their high-energy needs. Migratory birds may therefore be particularly vulnerable to global change processes that are projected to alter the quality and quantity of resource availability. Because long-distance flight requires high and sustained aerobic capacity, even minor decreases in vitality can have large negative consequences for migrants. In the light of this, we assess how current global change processes may affect the ability of birds to meet the physiological demands of migration, and suggest areas where avian physiologists may help to identify potential hazards. Predicting the consequences of global change scenarios on migrant species requires (i) reconciliation of empirical and theoretical studies of avian flight physiology; (ii) an understanding of the effects of food quality, toxicants and disease on migrant performance; and (iii) mechanistic models that integrate abiotic and biotic factors to predict migratory behaviour. Critically, a multi-dimensional concept of vitality would greatly facilitate evaluation of the impact of various global change processes on the population dynamics of migratory birds.

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Section: Resource Phenology and Weather Conditions (A) Weather Conditmentioning

confidence: 99%

Ecophysiology of avian migration in the face of current global hazards

Klaassen

Hoye

Nolet

et al. 2012

Phil. Trans. R. Soc. B

114

View full text Add to dashboard Cite

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“…Redheads on non-wintering areas frequently feed on the leaves and shoots of Potamogeton spp., Ruppia maritima, and other species of submersed aquatic plants during the warmer months when aboveground biomass is much greater (Bartonek and Hickey 1969, Bergman 1973, Bailey and Titman 1984, Noyes and Jarvis 1985, Jarvis and Noyes 1986, Woodin and Swanson 1989. Thus, redheads are behaviorally and morphologically capable of ingesting and digesting leaves and shoots of submersed aquatic plants that are similar to Halodule (Lagerquist and Ankney 1989).…”

Section: Discussionmentioning

confidence: 87%

Winter biomass and nutrient values of three seagrass species as potential foods for redheads (Aythya americana eyton) in Chandeleur Sound, Louisiana

Michot¹,

Chadwick²

1994

Wetlands

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Abstract:We studied biomass and macronutrient content of Halodule wrightii (shoalgrass) throughout the winter and of Thalassia testudinum (turtlegrass) and Syringodium fitiforme (manateegrass) in January in Chandeleur Sound, Louisiana. Halodule, the primary food of wintering redheads, had the lowest biomass of the three species on the study area in mid-winter. Macronutrient content of Halodule did not change during the winter, but aboveground and belowground biomass showed a 90 and 49% (P < 0.0001) decrease from October to March. Macronutrient content seems not to be the basis for selection by redheads of Hatodule over the other two seagrass species or of selection of belowground over aboveground parts.

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“…Few marked birds used very shallow areas with low open area (low visibility) regardless of edge density, and probability of use remained low at median water depths/open area. With deeper water and larger open area, birds could detect threats at greater distances and could chose to swim behind emergent vegetation (Oring , Bergman ) to avoid detection or more readily dive and disperse away from more imminent threats. Some species seem to use cover to minimize detection or as shelter, while others avoid such visual obstruction or alter their behavior.…”

Section: Discussionmentioning

confidence: 99%

Habitat selection by postbreeding female diving ducks: influence of habitat attributes and conspecifics

Austin

O’Neil

Warren

2016

Journal of Avian Biology

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Habitat selection studies of postbreeding waterfowl have rarely focused on within-wetland attributes such as water depth, escape cover, and food availability. Flightless waterfowl must balance habitat selection between avoiding predation risks and feeding. Reproductively successful female ducks face the greatest challenges because they begin the definitive prebasic molt at or near the end of brood rearing, when their body condition is at a low point. We assessed the relative importance of habitat attributes and group effects in habitat selection by postbreeding female lesser scaup Aythya affinis on a 2332-ha montane wetland complex during the peak flightless period (August) over seven years. Hypothesis-based habitat attributes included percent open water, open water:emergent edge density, water depth, percent flooded bare substrate, fetch (distance wind can travel unobstructed), group size, and several interactions representing functional responses to interannual variation in water levels. Surveys of uniquely marked females were conducted within randomly ordered survey blocks. We fitted two-part generalized linear mixed-effects models to counts of marked females within survey blocks, which allowed us to relate habitat attributes to relative probability of occurrence and, given the presence of a marked female, abundance of marked individuals. Postbreeding female scaup selected areas with water depths  40 cm, large open areas, and intermediate edge densities but showed no relation to flooded bare substrate, suggesting their habitat preferences were more influenced by avoiding predation risks and disturbances than in meeting foraging needs. Grouping behavior by postbreeding scaup suggests habitat selection is influenced in part by behavioral components and/or social information, conferring energetic and survival benefits (predation and disturbance risks) but potentially also contributing to competition for food resources. This study demonstrates the importance of incorporating group effects and interannual variability in habitat conditions when investigating habitat selection, particularly for seasons when waterfowl are aggregated.

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Use of Southern Boreal Lakes by Postbreeding Canvasbacks and Redheads

Cited by 20 publications

References 6 publications

Ecophysiology of avian migration in the face of current global hazards

Ecophysiology of avian migration in the face of current global hazards

Winter biomass and nutrient values of three seagrass species as potential foods for redheads (Aythya americana eyton) in Chandeleur Sound, Louisiana

Habitat selection by postbreeding female diving ducks: influence of habitat attributes and conspecifics

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