A 2009 paper proposed the new monotypic genus Amadonastur for it but this treatment has not been accepted by worldwide taxonomic systems.

Immatures are similar to adults but with dark streaks on their crown and neck, brown tips on some upperparts feathers, and white barring on the black base of their tail.

[4] The white-necked hawk is generally sedentary but there is some evidence of wandering or dispersal from its usual habitat.

[4] The white-necked hawk takes its prey on the ground, dropping from a perch that may be as low as 1.5 m (4.9 ft) high.

Others maintain that it is more of a generalist with a diet of arthropods, reptiles, amphibians, mammals, birds, and snails.

As of late 2022 xeno-canto had only one recording of a white-necked hawk and the Cornell Lab of Ornithology's Macaulay Library had three.