Blinking on pecking
A striking feature of some birds is that they blink when they peck. With each peck, just before the moment of impact, the nictitating membrane deploys. Examples are provided in a chicken (Gallus gallus domesticus) and a domestic turkey (Meleagris gallopavo).
Four pecks associated with nictitating membrane blinking in a chicken, played at 10% speed.
130ms after the head begins to move and immediately before the beak strikes the fruit coated surface, the nictitating membrane deploys. The lower lid also rises a little.
Blink on pecking in a domestic turkey. The nictitating membrane appears 200ms after the head movement begins.
Zebra doves (Geopelia striata) also blink on pecking, but using the upper lid as well as the nictitating membrane (Figure 3).
Brief upper lid blink on pecking in a zebra dove. It is first seen in the 40ms frame and has ended after the strike, in the 160ms frame.
Upper lid blinking on pecking in a laughing dove (Spilopelia senegalensis). Played at 20% speed.