Mobbing is when birds group together and appear to be mobbing a bird for their own protection…to drive it away. There are a number of issues. Often various species mob a bird such as a hawk or owl. In our case it’s unlikely they can drive our Owl off her nest or the eggs will be unprotected ..more of an issue during daytime. At night it’s safer for her to leave the eggs or young for brief times, for food. As and get a little older the mother might be off the nest,when still light, but one of the owls will usually be nearby guarding, if someone tries to get to the nest. As the owlets become large and need more food the parents may be seen out hunting when it’s still light to keep up with the food demand If a hawk or owl is just roosting in a tree, birds will often successfully drive it off by mobbing it..BUT occasionally the large bird being mobbed may grab one of the attackers. During the spring and summer when more species of birds are nesting, you may see many different size species of birds attacking a variety of birds that are threatening their nest or territory….(sort of “stay away and don’t come back”) When you hear a lot of noise from birds especially crows, it’s a good opportunity to look for a hawk or owl. You can often see Blue Jays (the policeman of the bird world) harassing a Coopers hawk with the help of many other species.