There are certain reflexes present in babies that disappear soon after birth. It’s easy for a new parent to think that these motions might be a sign that something is wrong when it’s really a lack of these that’s a troubling sign. NY Metro Parents published a piece on some of these reflexes.
Two of these are related to feeding, the rooting and the sucking reflex. If you touch a baby on the mouth, they’ll turn their heads and open their mouths to look for a nipple. If you press on the roof of their mouth, they will start to suck.
Another is the tonic neck reflex. A baby lying down with their head turned to the side will extend the arm on the same side and bend the other arm at the elbow. It is thought that this might be a way to keep balance.
The startle reflex is one that worries parents because babies may cry after it happens. It’s a reaction to sudden movements. The baby will throw out their arms and legs, then draw them back in. This reflex will kick in even during sleep and can wake a baby up.
For full details on these reflexes and two others, take a look at the full article linked above.