At 0720 (MST) on 12 May 1976, while conducting bird census work on the Idaho National Engineering Laboratory (INEL) 2 km west of Atomic City, Bingham Co., Idaho, we noticed a Horned Lark (Eremophila alpestris) dead on the road and a conspecific acting strangely nearby. Observing the birds from our vehicle, we recorded the following information from a distance of 5 m.