An invasive species is a plant or animal not native to a specific location. A non-native species has been introduced to an area. Technically, not all non-native species are invasive, if they have adapted to the different ecosystems and are not harmful.
Invasive birds were introduced to America by way of humans and naturally. In a natural way, a bird just flew over from somewhere else and stayed. Humans have contributed in a couple ways, they have brought birds from one region to another deliberately or by accident. A House Sparrow was brought to America by European settlers simply because they liked them. Some bird species have been brought over as “pets” and escaped, thus adapting to their new location and staying. Some bird were brought over accidentally because they were stow-away’s on ships or planes.
An invasive species have a tendency to multiply or spread, which can cause damage to the natural environment. Invasive birds can be a problem for wildlife, agriculture, or even human health. For wildlife, the damage can be disrupting ecological predator/prey balance. For birds specifically, they are competition for nesting sights and food supplies. Invasive birds will consume agricultural crops and can spread disease through their bird droppings. Some measures have been taken to get rid of invasive or non-native birds by way of poisoning, trapping, hunting, or nest destruction. Some birds considered an invasive species that I have seen in my neighborhood include: the House Sparrow, Rock Pigeon, European Starling, Mallard, and Canada Goose.
For many, nothing will make them like an invasive or non-native bird, even though it is not their fault they are here. I suggest making your yard bird friendly, but make sure the food is for native birds and the bushes and flowers are native species to the area. This can definitely be a contentious subject that will probably not go away, as many of those birds seem here to stay.