There was an error published in J. Exp. Biol.216, 3035-3046.

The authors inadvertently omitted to declare a competing interest for one of the authors. The correct Competing Interests statement is given below.

J.S.B. owns the company (Positive Science) that manufactured the eye-tracking headpiece and designed the eye-tracking software, which were used in the experiments described within this manuscript.

The authors apologise for any inconvenience that this error may have caused, but assure readers that it does not affect the results or conclusions of the paper.