Composition of Wood Duck Eggs in Relation to Egg Size, Laying Sequence, and Skipped Days of Laying

Abstract

We collected 138 freshly laid Wood Duck (Aix sponsa) eggs from 13 nests to determine the effects of egg size, laying sequence, and skipped laying days on egg composition. All components except yolk ash and eggshell, both wet and dry, increased in direct proportion to fresh-egg mass. Egg size increased during the first half of laying and decreased thereafter. The effects of laying sequence were component-specific. Absolute levels of neutral lipids (comprising 65.6% of dry yolk) were near average until about 75% of the clutch was completed and then declined. Mass of albumen components tended to increase sharply with the first few eggs and then decrease as laying progressed. Fat indices (egg lipid/lean dryegg content) tended to be highest in the first 40% of the clutch. We interpret laying-sequence effects on egg composition as adaptations that enable female Wood Ducks to initiate incubation before clutch completion and still allow for synchronous hatching without compromising the hatching success of first-laid eggs. Hens frequently skipped a laying day between the penultimate and ultimate egg, which tended to increase the mass of the yolk component in last-laid eggs compared with those that were laid the day following the penultimate egg.

Parental food conditions affect sex-specific embryo mortality in the yellow-legged gull (Larus michahellis)

“…If the maternal condition of gulls was manipulated by supplementary feeding, extra protein diets increase yolk content of the c-egg (Bolton et al 1992). Maternal effects that operate via the eggs may be important and, for instance, larger eggs provide greater lipid and water resources (Williams 1994;Kennamer et al 1997). Nevertheless, in our experiment egg size and the interaction between egg size and sex did not affect embryo survival.…”

Factors Influencing Incubation Egg-Mass Loss for Three Species of Waterfowl

“…We also considered the possibility that eggs laid by an individual Wood Duck may vary in size more than those laid by an individual Common Goldeneye. The Wood Duck lays smaller eggs at the beginning and end of the laying cycle, with larger eggs in the middle, so variation within a female can be quite substantial (Kennamer et al 1997). Hepp et al (1987) and Kennamer et al (1997) reported considerable variation among eggs (CV 8.0%, 4.0%, 2.7% and 6.4%, 3.5%, 2.4% for mass, length, and breadth, for each respective study).…”

“…The Wood Duck lays smaller eggs at the beginning and end of the laying cycle, with larger eggs in the middle, so variation within a female can be quite substantial (Kennamer et al 1997). Hepp et al (1987) and Kennamer et al (1997) reported considerable variation among eggs (CV 8.0%, 4.0%, 2.7% and 6.4%, 3.5%, 2.4% for mass, length, and breadth, for each respective study). The Bufflehead (Bucephala albeola) and Barrow's Goldeneye (B. islandica) vary comparably in these same egg measurements with CVs of 5.89%, 3.33%, 2.13% and 5.04%, 3.06%, 2.10%, respectively (Lavers et al 2006).…”

Maternal effects of egg size on emuDromaius novaehollandiaeegg composition and hatchling phenotype

“…Thus, it seems that altricial species change egg size by increasing the amount of albumen while keeping yolk content relatively constant, whereas precocial species tend to alter egg size by increasing both yolk and albumen content with an increase in egg mass. Further support for this pattern has been observed in precocial wood ducks Aix sponsa (Kennamer et al, 1997) and ruddy ducks Oxyura jamaicensis (Pelayo and Clark, 2002), which lay eggs having yolk and albumen varying isometrically with egg mass, and in altricial great tit Parus major eggs, in which much of the variation in egg mass is attributable to variation in albumen mass (Lessells et al, 2002).…”