Intraclutch egg-size variation and hatching success in the common eider

1993 ◽  
Vol 71 (3) ◽  
pp. 544-549 ◽  
Author(s):  
Gregory J. Robertson ◽  
Fred Cooke
Keyword(s):  
Egg Size ◽  
Hatching Success ◽  
Size Variation ◽  
Hudson Bay ◽  
Somateria Mollissima ◽  
Physiological Mechanisms ◽  
Common Eiders ◽  
Laying Sequence ◽  
The Common ◽  
Nutrient Reserves

Intraclutch egg-size variation and hatching success were studied in a population of Hudson Bay common eiders (Somateria mollissima sedentaria) at La Pérouse Bay, Manitoba (58°24′N, 94°24′W), to test the hypothesis that females allocate more nutrient reserves to eggs that are more likely to hatch. Egg volumes were calculated for 575 known-sequence eggs in 134 complete clutches of 3–6 eggs. In general, the length of eggs decreased linearly with position in the laying sequence, whereas the breadth of eggs followed a curvilinear pattern, the second or third egg being the widest. For all clutch sizes, the last-laid egg was the smallest and the second- or third-laid egg the largest. Hatching success also varied with position in the laying sequence. Pre-incubation failure declined over the laying sequence, whereas hatching failure (dead, infertile, or rotten eggs) increased. In all cases pre-incubation failure was the major cause of egg loss (84% of total loss). Overall, third and fourth eggs were the most successful and first eggs were the least successful. With one exception, successful and unsuccessful eggs were the same size within a laying sequence. We conclude that there is no clear relationship between egg size and hatching success, and that laying sequence per se has a greater effect on hatching success. Female eiders do not appear to allocate more reserves to eggs that are most likely to hatch, and we consider other proximate, physiological mechanisms to explain the observed pattern of intraclutch egg-size variation.

scholarly journals Condition dependent strategies of egg size variation in the Common Eider Somateria mollissima

2019 ◽  
Author(s):  
Thomas Kjær Christensen ◽  
Thorsten Johannes Skovbjerg Balsby
Keyword(s):  
Clutch Size ◽  
Body Condition ◽  
Egg Size ◽  
Size Variation ◽  
Common Eider ◽  
Somateria Mollissima ◽  
Individual Level ◽  
Laying Sequence ◽  
The Common ◽  
Using Data

AbstractWe analysed intraclutch egg-size variation in relation to clutch size and to female body condition in the Common Eider Somateria mollissima during an 8-year period. The aim was to assess if eiders adaptively adjusted egg size within the laying sequence in response to different clutch sizes, which potentially could optimise reproductive success through a size advantage in hatchlings. The analyses were performed on both population and individual level using data from recaptured females that changed clutch size between seasons. Based on 1,099 clutches from 812 individual females, population clutch size averaged 4.13 eggs (range: 1-6), with marked annual variation in the dominance of 4- and 5-egg clutches, which constituted c.70% of all clutches. Clutch size was positively related to female pre-laying body condition at both the population and individual level. Egg size varied significantly within and between clutch sizes and changes were significantly related to the laying sequence. First eggs were significantly larger in 4-egg clutches and second eggs smaller (marginally insignificant) than in 5-egg clutches, a pattern also found among individual females changing clutch size between seasons. The relationship between female pre-laying body condition, clutch size and the intraclutch egg-size pattern indicates that both clutch size and egg size is actively adapted to the pre-breeding body condition of the female. We suggest that the observed pattern of intraclutch egg-size variation reflects a finely tuned conditional dependent mechanisms that enable females in a suboptimal condition to optimize reproductive output.

Annual variation in common eider egg size: effects of temperature, clutch size, laying date, and laying sequence

1995 ◽  
Vol 73 (9) ◽  
pp. 1579-1587 ◽  
Author(s):  
Gregory J. Robertson
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Annual Variation ◽  
Size Variation ◽  
Egg Laying ◽  
Laying Date ◽  
Somateria Mollissima ◽  
Ambient Temperatures ◽  
Common Eiders ◽  
N 93

Annual variation in volumes of eggs laid by common eiders (Somateria mollissima sedentaria) nesting at La Pérouse Bay, Manitoba (58°43′N, 93°27′W), was studied over 3 years (1991–1993). Temperatures during the egg-laying period were higher in 1991 than in 1992 and 1993. However, the eiders began nesting in 1993 at the same time as in 1991, whereas in 1992 the eiders began laying approximately 2 weeks later. Eiders laid significantly smaller clutches in 1992 than in the other 2 years. Egg size did not correlate with clutch size or laying date in any year. However, eiders laid smaller eggs in 1992 and 1993 than in 1991. In five egg clutches, the pattern of intraclutch egg-size variation was different among years. The last laid eggs of five egg clutches were disproportionately smaller in 1992 and 1993 (cold years) than those laid in 1991. Minimum daily temperatures before the egg-laying period (during rapid yolk development) were positively correlated with egg size. However, this effect was not significant when year and egg sequence were controlled for. Egg-size variation was correlated with the overall ambient temperatures during the laying period, whereas annual clutch-size variation was correlated with laying date, suggesting that the proximate mechanisms affecting clutch and egg size are different.

scholarly journals Condition dependent strategies of egg size variation in the Common Eider Somateria mollissima

PLoS ONE ◽  
2020 ◽  
Vol 15 (7) ◽  
pp. e0226532
Author(s):  
Thomas Kjær Christensen ◽  
Thorsten Johannes Skovbjerg Balsby
Keyword(s):  
Egg Size ◽  
Size Variation ◽  
Common Eider ◽  
Somateria Mollissima ◽  
The Common

Adaptive aspects of intraclutch egg-size variation in the High Arctic barnacle goose (Branta leucopsis)

2002 ◽  
Vol 80 (7) ◽  
pp. 1180-1188 ◽  
Author(s):  
Christiaane E Hübner ◽  
Ingunn M Tombre ◽  
Kjell E Erikstad
Keyword(s):  
Egg Size ◽  
Hatching Success ◽  
Size Variation ◽  
High Arctic ◽  
Hatching Asynchrony ◽  
Nutrient Allocation ◽  
Egg Predation ◽  
Barnacle Goose ◽  
Laying Sequence ◽  
Branta Leucopsis

The pattern of intraclutch egg-size variation in barnacle goose (Branta leucopsis) clutches and its adaptive implications was studied in Svalbard, Norway, from 1989 to 1998. Egg size was measured in relation to laying sequence, egg predation and hatching order were recorded to determine hatching success of eggs in different laying sequences, and the time when incubation started was examined. Egg size showed a rather consistent pattern, with a large second-laid egg and declining egg size for the remainder of the clutch. The first-laid egg was usually smaller than the second one, except in clutches with two and three eggs. Predation was highest for the first-laid egg, and last-laid eggs hatched last in most cases, although only one last-laid egg was abandoned. Four of six females started incubation before clutch completion. Both the "nutrient-allocation hypothesis" as well as the "early incubation start hypothesis" may contribute to explaining the expressed pattern of intraclutch egg-size variation. The fitness gains due to allocating fewer nutrients to eggs in unfavourable positions in the laying sequence may explain the small size of the first egg, whereas the multiple benefits of an early incubation start may have led to the decline in egg size later in the laying sequence as a mechanism to counteract hatching asynchrony.

Female sociality in the common eider duck during brood rearing

1982 ◽  
Vol 60 (12) ◽  
pp. 3326-3331 ◽  
Author(s):  
J. K. Schmutz ◽  
R. J. Robertson ◽  
F. Cooke
Keyword(s):  
Maternal Care ◽  
Adaptive Significance ◽  
Common Eider ◽  
Somateria Mollissima ◽  
Brood Rearing ◽  
The Common ◽  
Nutrient Reserves ◽  
Prolactin Hormone

This study investigates the potential adaptive significance of the behavior of female common eider ducks (Somateria mollissima) which have no young of their own ("aunts") but accompany other females and young. "Aunts" exhibited ambivalent aggression and protection toward ducklings. There was no evidence that the presence of "aunts" enhanced the survival of the ducklings they accompanied. Both females which had their clutch removed and females which had not laid eggs behaved as "aunts." The level of circulating prolactin hormone in "aunts" was lower than in incubating females and similar to the basal level of males. We therefore rejected the hypothesis that maternal care was misdirected during hormonal adjustment from breeding to nonbreeding. We suggest that "aunts" which have lost a clutch or brood, spend some time feeding away from the colony, and then return to the nesting grounds after replenishing their nutrient reserves. Upon returning, "aunts" may select sites for nesting in future years. During this time, they are temporarily attracted to broods. We propose that "aunts" flock and fend off predators during an attack in an attempt to seek safety in a flock rather than to protect ducklings of other females.

Factors affecting egg viability and incubation time in prairie dabbling ducks

1993 ◽  
Vol 71 (6) ◽  
pp. 1146-1152 ◽  
Author(s):  
Todd W. Arnold
Keyword(s):  
Clutch Size ◽  
Incubation Time ◽  
Egg Size ◽  
Hatching Success ◽  
Size Variation ◽  
Negative Effects ◽  
Factors Affecting ◽  
Ambient Temperatures ◽  
Weak Support ◽  
Anas Clypeata

I determined hatching success for 328 dabbling duck (Anas spp.) eggs that were experimentally subjected to varying lengths of preincubation delay and then artificially incubated. Hatchability declined as unincubated eggs were exposed to longer preincubation delays. This effect was more pronounced at higher ambient temperatures and later in the nesting season, but did not vary with egg size or among duck species. These results are largely consistent with observed patterns of clutch-size variation among prairie-nesting waterfowl. Clutch size may be smaller later in the year and at lower latitudes owing to the negative effects of date and temperature on the ability of eggs to withstand preincubation delay. The timing of embryo mortality was bimodal, with peaks occurring during early development (<6 d) and just before hatching (>22 d); however, only early mortality was affected by preincubation delay. Eggs lost up to 2.6% of their initial mass as water vapor during preincubation delay, but the amount of water loss did not affect hatching success. Eggs subjected to preincubation delay required about 1 additional day to hatch. Incubation time was related to egg size in northern shovelers (Anas clypeata) and in all species combined, but not in blue-winged teal (Anas discors) or mallards (Anasplatyrhynchos). These data provide only weak support for the hypothesis that large eggs are costly because they take longer to hatch.

Parental care in the common eider (Somateria mollissima): factors affecting abandonment and adoption of young

1991 ◽  
Vol 69 (6) ◽  
pp. 1538-1545 ◽  
Author(s):  
Jan O. Bustnes ◽  
Kjell E. Erikstad
Keyword(s):  
Parental Care ◽  
Somateria Mollissima ◽  
Factors Affecting ◽  
Lower Survival Rate ◽  
Duckling Survival ◽  
Energetic Stress ◽  
Lower Body Weight ◽  
Common Eiders ◽  
The Common ◽  
Individual Strategies

Parental care in common eiders (Somateria mollissima) was studied during three field seasons in northern Norway. Forty-two percent of the females were found to abandon their brood. Abandonment and tending of broods and crèches were not obligate individual strategies, but changed between years. Females abandoning their young laid smaller clutches and had a lower body weight at hatching than brood- and crèche-tending females, indicating that they were in poor body condition. This supports the hypothesis that abandoning the brood is a salvage strategy in which energetic stress limits females' ability to care for their young. Young of "abandoners" seemed to have a lower survival rate than young of "tenders," which suggests a reproductive cost of abandoning the young. Forty-seven percent of tagged ducklings were found with females other than their mother. Twenty-seven percent of the brood- and crèche-tending females lost young to other females, but never more than one duckling. Adoptions of foreign ducklings, above the normal brood size of four, did not lead to greater parental effort, and duckling survival was similar among broods and crèches of different sizes. This suggests that adoptions may be of neutral adaptive value. Two females often formed stable crèches, but duckling survival was not significantly different from that in broods and crèches with single females.

Clutch, egg and body size variation among common eiders breeding in Hudson Bay, Canada

2001 ◽  
Vol 20 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Gregory J. Robertson ◽  
Austin Reed ◽  
H. Grant Gilchrist
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Hudson Bay ◽  
Body Size Variation ◽  
Common Eiders

scholarly journals Physical Condition of an Animal, Using as an Example the Common Eider, Somateria mollissima

2003 ◽  
Vol 117 (2) ◽  
pp. 230 ◽  
Author(s):  
Arnaud J. Cabanac
Keyword(s):  
Physical Condition ◽  
Somateria Mollissima ◽  
Energy Reserves ◽  
Stored Energy ◽  
Survival Chance ◽  
Available Energy ◽  
Common Eiders ◽  
The Subject ◽  
The Common ◽  
Time Of Year

An index of the physical condition of an animal should describe its endogenous available energy. The welfare of the animal depends on its ability to spend its stored energy (lipid and protein) in order to survive the environmental and behavioural challenge at the particular time of its capture. I propose a new index to predict the survival chance of the subject. The new index of physical condition takes into account the available endogenous energy reserves and the known needs of the species at that particular time of year. I further illustrate this new method of estimating the physical condition by running a trial with Common Eiders, Somateria mollissima.

Colonial nesting of the Hudson Bay eider duck

1983 ◽  
Vol 61 (11) ◽  
pp. 2424-2433 ◽  
Author(s):  
Josef K. Schmutz ◽  
Raleigh J. Robertson ◽  
Fred Cooke
Keyword(s):  
Open Water ◽  
Alarm Calls ◽  
Hudson Bay ◽  
Somateria Mollissima ◽  
Small Islands ◽  
Social Cooperation ◽  
Artificial Nests ◽  
Colonial Nesting ◽  
Common Eiders ◽  
Selection Of

This study was designed to evaluate the factors influencing colonial nesting of the Hudson Bay eider duck (Somateria mollissima sedentaria). Colonial nesting reflected both selection of appropriate nesting habitat by female common eiders and advantages gained through social cooperation in predator defense. Female common eiders preferred to nest on small islands or on promontories near the shore and under shrubs of medium height. Nesting densities were greatest where a relatively large expanse of open water facilitated landing and taking flight. Nesting females gave alarm calls and formed dense flocks in response to a fox model. Egg predation was less in artificial nests which were close to an incubating female than in those situated further away. There was no correlation between degree of nesting synchrony and density of females on an island. Certain groups, however, exhibited greater nesting synchrony than expected by chance and the variance in egg shape among these females suggested that they were genetically related.

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