Weights and Primary Growth of Brent Geese Branta bernicla Moulting in the Queen Elizabeth Islands, N.W.T., Canada, 1973-1975

Abstract

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Variation in body mass dynamics among sites in Black BrantBranta bernicla nigricanssupports adaptivity of mass loss during moult

“…Thus, our analysis functionally examined variation in mass, adjusted for moult stage and structural body size. We included YEAR, SEX and AGE as fixed factors because previous studies of moulting Black Brant had shown them to be important (Boyd & Maltby , Ankney , Taylor , Lewis et al . ).…”

“…, ). Lastly, some waterfowl are capable of flight prior to the completion of feather regrowth (Boyd & Maltby , Ankney , Taylor ). The wing load reduction hypothesis proposes that mass loss during moult is adaptive in that it reduces wing loading and so allows the lighter birds to regain the ability to fly sooner (Douthwaite , Owen & Ogilvie ).…”

Timing of adult remigial wing molt in female Black Brant (Branta bernicla nigricans)

“…Brant molting on the North Slope (70°N) experience continuous daylight during the molt, in contrast to the YKD, where brant may experience 5 h day -1 of darkness during the molt (Sedinger and Raveling 1988). Boyd and Maltby (1980) hypothesized that the longer days experienced by geese at high latitudes would enable them to grow feathers more rapidly than geese molting at lower latitudes. Additionally, brant on the YKD were tending broods, which may have reduced their foraging time for vigilance or other behaviors associated with brood care (Sedinger et al 1995a, Fowler andEly 1997), compared with brant in molting flocks.…”

“…In waterfowl, molt of the primaries and secondaries coincides with molt of body feathers and must be completed before fall migration (Taylor 1995; but see Hohman and Richard 1994), which can begin as early as mid-August (Barry 1962, Boyd andMaltby 1980). In Arctic-nesting geese, clutches hatch during late June or early July (Owen 1980, Sedinger andRaveling 1986), leaving 6-8 weeks for completion of wing molt before fall migration commences (Barry 1962).…”

Energetics and Nutrition of Molt

“…Young Sylvia atricapilla fed nutrient-poor berries also failed to delay the onset of their post juvenile molt, compared with conspecifics fed a nutrient-rich diet (Berthold 1976). Under natural conditions, some species of birds begin their molts when conditions become unfavorable for breeding (e.g., Keast 1968;Fogden and Fogden 1979;Boyd and Maltby 1980;Kasparek 1980). Cygnus columbianus restore energy reserves depleted during breeding during molt (Earnst 1992).…”