=+5.62 ● The paper “The Shelf Life of Bird Eggs: Testing Egg Viability Using a Tropical Climate Gradient” (Ecology [2005]: 2164–2175) investigated the effect of altitude and length of exposure on the hatch rate of thrasher eggs.

Data consistent with the estimated probabilities of hatching after a number of days of exposure given in the paper are shown here.

y¿ 5 lna p

1 2 p b

p 1 2 p Probability of Hatching Exposure

(days) 1 2 3 4 5 6 7 8 Proportion

(lowland) 0.81 0.83 0.68 0.42 0.13 0.07 0.04 0.02 Proportion

(midelevation) 0.73 0.49 0.24 0.14 0.037 0.040 0.024 0.030 Proportion

(cloud forest) 0.75 0.67 0.36 0.31 0.14 0.09 0.06 0.07