Developmental stage affects eggshell-breaking strength in two ground-nesting birds: the partridge (Alectoris rufa) and the quail (Coturnix japonica)
✍ Scribed by Aurora M. Castilla; Anthony Herrel; Guillém Díaz; Amadeu Francesch
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2007
- Tongue
- English
- Weight
- 114 KB
- Volume
- 307A
- Category
- Article
- ISSN
- 1932-5223
- DOI
- 10.1002/jez.400
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✦ Synopsis
Abstract
We examined the relationship between embryo development and egg hardness in two ground nesting bird species, the red‐legged partridge (Alectoris rufa; n = 165 eggs) and the quail (Coturnix japonica; n = 148 eggs). For both species, we observed a strong effect of developmental stage on egg hardness. Eggs near hatching were significantly weaker than unincubated eggs (partridge: 18 and 23 N, respectively, and the quail 7 and 10 N, respectively). We additionally explored the effect of incubation on egg hardness in a control sample of non‐fertilised quail eggs (i.e., without embryo development). The control eggs maintained in the incubator for the full incubation time (17 days) were significantly harder (7–9 N) than eggs containing fully developed chicks (5–7 N). Thus, the incubation conditions of high temperature and humidity alone seem not to have a significant effect on egg hardness, and support the important effect of calcium uptake. J. Exp. Zool. 307A:471–477, 2007. © 2007 Wiley‐Liss, Inc.