Table 3.

An illustration of the effects of shape and width in Model 5 using 2 sets of brown-headed cowbird eggs. Maintaining a constant egg shape (eggs A.1 and A.2) or width (eggs B.1 and B.2) yields changes in temperature variation (by a factor of 0.42 and −0.035, respectively) in cowbird eggs. Eggs with differing widths can have the same shape due to differences in length (eggs A.1 and A.2). Therefore, width only has an effect on temperature variation. Additionally, eggs with different shapes can have the same width (eggs B.1 and B.2), and as a result, shape only affects temperature variation

Egg	Length	Width	Shape	Effects of egg shape on temperature variation between eggs	Effects of egg width on temperature variation between eggs
A.1	19	14.25	0.75	−0.35 × 0 = 0	0.28 × 1.5 = 0.42
A.2	21	15.75	0.75
B.1	20	15	0.75	−0.35 × 0.1 = −0.035	0.28 × 0 = 0
B.2	17.6	15	0.85