A comparative study of egg mass and clutch size in the Anseriformes

Abstract

The factors explaining interspecific differences in clutch investment in precocial birds are poorly understood. We investigated how variations in clutch characteristics are related to environmental factors in a comparative study of 151 extant species of ducks, geese and swans (Anseriformes). Egg mass was negatively related to clutch size in a phylogenetic regression, a relationship that was much stronger when controlling for female mass. Nest placement was related to both egg size and clutch size, with cavity-nesting species laying more but smaller eggs. Egg size was positively correlated with incubation period and with female mass, and also with sexual size dimorphism (i.e. male mass relative to that of the female). Clutch size was not related to female mass. Species with long term pair bonds laid smaller clutches and larger eggs. The size of the breeding range was strongly positively correlated with clutch size and clutch mass, and its inclusion in multivariate models made other biogeographical variables (hemisphere, breeding latitude or insularity) non-significant. The small clutches in insular species appear to be a product of small range size rather than insularity per se. Our results suggest there is an evolutionary trade-off between clutch and egg size, and lend support to Lack's resource-limitation hypothesis for the waterfowl.

New Insights into Non-Avian Dinosaur Reproduction and Their Evolutionary and Ecological Implications: Linking Fossil Evidence to Allometries of Extant Close Relatives

“…Our results corroborate that body mass and reproductive investment (in terms of egg mass, clutch mass or annual clutch mass) are highly correlated in extant reptiles and birds [9,11–17]. In amniotes, the relative reproductive investment generally declines with body mass, whereas the absolute reproductive investment increases ( [16,46], Figures 1-3, Table S3).…”

“…[6–8]). While the correlations between clutch/litter size or annual offspring number and body mass differ between different extant amniotic taxa [4,5,9,10], mass specific reproductive traits such as egg mass, clutch mass and annual reproductive mass (clutch mass × number of clutches per year) do significantly, positively correlate with body mass [9,11–17]. The relationships between traits (Y) and body mass (BM) follow a power function Y =  c  × BM b , where c is a normalization constant and b is an exponent.…”

Seasonal clutch size decline and individual variation in the timing of breeding are related to female body condition in a non-migratory species, the Upland Goose Chloephaga picta leucoptera

“…Interestingly, we found that egg size increased with increasing clutch size. Other studies on waterfowl have already shown that the theoretical trade-off between size and number of offspring as proposed by Lack (1968) can be observed on an interspecific level (Figuerola and Green 2006), but is not always present on an intraspecific level (Christians 2000; see Christians 2002 for a review). The intraspecific relationship does not show a consistent pattern, as there was no correlation between egg size and clutch size in some species but a positive correlation in others (see Christians 2002 for a review).…”

Temperature during egg formation and the effect of climate warming on egg size in a small songbird

“…Hendricks, 2003), including the pied flycatcher (Murphy and Haukioja, 1986;Lundberg and Alatalo, 1992;Both and Visser, 2005). This, at least theoretically, could play a role against increases in egg size due to the possibility of subtle trade-offs between egg and clutch sizes (Nager et al, 2000;Christians, 2002;Figuerola and Green, 2006). However, in addition to the 'stasis' of breeding dates in this population, there has been no indication that clutch size has changed in a significant way across the study period (Sanz et al, 2003), falsifying the idea that decreases in egg size might be linked to increases in clutch size concurrent with slight advancements in breeding date.…”