Table 1.

Ethogram of behaviors observed through video recorded during the startle test.

Behavior	Description
Flight distance	Following umbrella opening, furthest distance from feed pan traveled during initial continuous motion; measured to nearest painted ground line from feed pan in meters
Walking	Moving at walking gait; frequency and duration
Trotting/cantering	Moving at either trotting or cantering gait; frequency and duration
Inactive attentive	Standing still with head and ears directed towards the umbrella; frequency and duration
Inactive not attentive	Standing still with head and ears faced away from the umbrella; frequency and duration
Latency to return to feed pan	Latency, following umbrella opening, to return to feed pan, lower head, and resume feeding. Assigned an upper limit of 300 s if the horse did not return.