- Coloured figures of the birds of the British islands, vol. 1
- Powys, Thomas 4th Baron Lilford (issued by)
- London, 1885-1897
- Open Library:
- View record.
The gyrfalcon (Falco rusticolus) is the largest of all falcons. It is found in the northern hemisphere, where it breeds in the Arctic regions. Its color ranges from white, to brown, to black. The above illustration, made after Joseph wolf, shows the brown morph.