Which of the following is classified as a non-kosher bird?

A hawk is classified as a non-kosher bird primarily because, according to kosher dietary laws, birds of prey are prohibited. The Torah provides specific guidelines regarding which birds are permitted for consumption, and they tend to be domestic or non-predatory species.

In contrast, ducks, quails, and chickens are generally considered kosher. These birds are not predators and do not fall into the category of birds that are forbidden under Jewish dietary laws. Therefore, the classification of the hawk as non-kosher aligns with these dietary restrictions, making it the correct choice in this context. The emphasis on the distinction between predatory and non-predatory birds is crucial when determining kosher status.