Table 2. Partial regression coefficients and robust standard errors for standardized variables in the best model (lowest AIC; Table 1) for the probability that a Magellanic penguin chick died in a storm at Punta Tombo, Argentina, 1983–2010.

Predictor variables	Coefficient	Robust standard error
Age	−3.97	0.60
Age * Rain	−3.48	0.53
Age squared * Rain	3.42	0.54
Age squared	−2.64	0.51
Age squared * Rain * Low	2.06	0.37
Age squared * Low	1.32	0.25
Rain	1.31	0.23
Intercept	−3.24	0.26

We used multiple logistic regression, grouping on nest, with robust standard errors on 2482 chicks in 590 nests with 233 storms. Age = chick age (days) on date of storm (chicks that did not die in a storm were randomly assigned to a storm), Low = low temperature, * indicates interaction terms. Variables were standardized so the coefficient magnitudes indicate their relative strengths.