thumb|Foot bones of Haast's eagle (top) and those of its closest living relative, the little eagle It had a relatively short wingspan for its size. It is estimated that the grown female typically spanned up to , possibly up to in a few cases. This wingspan is broadly similar to the larger range of female size in some extant eagles: the wedge-tailed eagle, golden eagle (A. chrysaetos), martial eagle (Polemaetus bellicosus), white-tailed eagle (Haliaeetus albicilla) and Steller's sea eagle (Haliaeetus pelagicus) are all known to exceed in wingspan. Several of the largest extant Old World vultures, if not in mean mass or other linear measurements, probably exceed Haast's eagle in average wingspan as well. Haast's eagle's relatively short wingspan has sometimes led it to being incorrectly portrayed as having evolved toward flightlessness, even though evidence strongly suggests that it flew. Instead, its short and broad wings represents an evolutionary departure from the mode of its ancestors' soaring flight in favour of navigating through a crowded woodland environment. Haast's eagles are likely to have hunted within the dense shrubland and forests of New Zealand, somewhat akin to other forest-dwelling raptors like the goshawks or harpy eagle.
thumb|Foot bones of Haast's eagle (top) and those of its closest living relative, the little eagle It had a relatively short wingspan for its size. It is estimated that the grown female typically spanned up to , possibly up to in a few cases. This wingspan is broadly similar to the larger range of female size in some extant eagles: the wedge-tailed eagle, golden eagle (A. chrysaetos), martial eagle (Polemaetus bellicosus), white-tailed eagle (Haliaeetus albicilla) and Steller's sea eagle (Haliaeetus pelagicus) are all known to exceed in wingspan. Several of the largest extant Old World vultures, if not in mean mass or other linear measurements, probably exceed Haast's eagle in average wingspan as well. Haast's eagle's relatively short wingspan has sometimes led it to being incorrectly portrayed as having evolved toward flightlessness, even though evidence strongly suggests that it flew. Instead, its short and broad wings represents an evolutionary departure from the mode of its ancestors' soaring flight in favour of nav?igating through a crowded woodland environment. Haast's eagles are likely to have hunted within the dense shrubland and forests of New Zealand, somewhat akin to other forest-dwelling raptors like the goshawks or harpy eagle.