Data from: The pyriform egg of the Common Murre (Uria aalge) is more stable on sloping surfaces

• Main Authors: Birkhead, Tim R., Thompson, Jamie E., Montgomerie, Robert
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2018
• Subjects: Alca torda; Uria alle; Egg shape; Holocene; Common Murre; Razorbill; Uria aalge; uria
• Online Access: https://doi.org/10.5061/dryad.gb90p1c

The adaptive significance of avian egg shape is a long-standing problem in biology. For many years, it was widely believed that the pyriform shape of the Common Murre (Uria aalge) egg allowed it to either "spin like a top" or "roll in an arc," thereby reducing its risk of rolling off the breeding ledge. There is no evidence in support of either mechanism. Two recent alternative hypotheses suggest that a pyriform egg confers mechanical strength and minimizes the risk of dirt contamination of the blunt end. We present a new hypothesis: that the Common Murre egg's pyriform shape confers stability on the breeding ledge, thus reducing the chance that it will begin to roll. We tested this hypothesis by measuring the stability of Common Murre and Razorbill (Alca torda) eggs of different shapes on slopes of 20°, 30°, and 40° above the horizontal. Common Murre eggs were more stable, and easier to stabilize, than the more elliptical Razorbill eggs. Within Common Murre eggs, more pyriform eggs were more stable. From a fitness perspective, the stability of the Common Murre egg on a slope seems likely to confer an advantage and thus may be a strong force of natural selection favoring the pyriform shape. README stabilityRcode R notebook used to generate the Statistical Supplement Statistical Supplement This is the Rcode and output from that code for the statistical analyses reported in this paper. StatisticalSupplement.pdf Comparing stability on different slopes This is the dataset from slope trials done by Jamie Thompson (JET) alone, to assess his ability to stabilize Razorbill and Common Murre eggs of different shapes on flat, sandpaper covered slopes of 20°, 30° and 40° above the horizontal. stability.csv Static slopes experiment comparing participants This is a dataset to compare the ability of 12 naive subjects with a potentially biased subject (Jamie E Thompson; JET) in their ability to balance Razorbill and Commmon Murre eggs on surfaces with different slopes. studentdata.csv Data from moving slopes experiment This ...