If you are a photographer interested in wildlife, you should always be aware of what is around you. This is especially true when photographing young animals.
The parents are often close by and may decide that you are a danger to their young. Knowing a species signs of aggravation may save you and your gear from being attacked. Waterfowl are known to bob their heads, hiss, and flap their wings before attacking. If you see these signs back off. You’re too close according to them.