September 7, 2005
Blackwell Publishing Ltd.
Most perching birds lay eggs speckled with reddish protoporphyrin spots toward the egg's blunt end. Evidence in a paper by Gosler, Higham & Reynolds soon to appear in Ecology Letters suggests that rather than giving a visual signal, protoporphyrins strengthen the eggshell by compensating for reduced eggshell-thickness caused by calcium deficiency. Pigment spots on great tit eggs specifically marked thinner areas of shell, and females nesting on low-calcium soils, laid thinner-shelled, more-spotted eggs.
Birds' eggs are unique in their diverse pigmentation. This diversity is greatest amongst perching birds (order Passeriformes: 60% of all bird species), which include many familiar species including tits and warblers. Despite intense interest, the purpose, in most species, of these patterns was unknown.
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Blackwell Publishing Ltd.. "Why Are Birds' Eggs Speckled?." ScienceDaily. ScienceDaily, 7 September 2005. <www.sciencedaily.com/releases/2005/09/050907095627.htm>.
Blackwell Publishing Ltd.. (2005, September 7). Why Are Birds' Eggs Speckled?. ScienceDaily. Retrieved March 8, 2014 from www.sciencedaily.com/releases/2005/09/050907095627.htm
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