Which of the following species is NOT considered an allowable bait species?

The American robin is not considered an allowable bait species because it is protected under the Migratory Bird Treaty Act in the United States. This act prohibits the hunting, capturing, or killing of migratory birds without a permit, which includes a wide range of bird species that inhabit the country, particularly those that are common and widely recognized, such as the American robin.

In the context of falconry, using bait species typically involves choosing birds that are not protected or regulated by federal law, which is why the other options, including the European starling, house sparrow, and Eurasian-collared dove, are allowable. These species are often viewed as invasive or non-native, and they do not enjoy the same protections as migratory birds like the American robin. Therefore, falconers must adhere to regulations that ensure the ethical treatment of wildlife while pursuing their sport, which establishes the American robin as an unsuitable choice for bait.