In the case of the eggs you found in your hanging basket, it is possible that a bird laid them there and then abandoned them. This can happen for a variety of reasons, such as if the bird is disturbed or if it does not find enough food to support itself and its young. It is also possible that the eggs were eaten by a predator, such as a squirrel or a cat.
If you find any more eggs in your hanging basket, you can try to relocate them to a more suitable nest. However, it is important to be aware that birds are protected by law, so you should only do this if you are sure that the eggs are abandoned. If you are not sure, you can contact your local wildlife rehabilitation center for advice.