It is easy to be confused between a falcon and a harrier Hawk (Kahu). At first glance they can appear similar, due to having a similar shape and colouring – but the differences are great.
The greatest difference is of course the numbers of each bird. The harrier Hawk is found in abundant numbers throughout New Zealand. Whereas the falcon is extremely rare.
The harrier Hawk is also larger than both the male and female falcons, in fact almost twice the size of a female falcon.
When flying the harrier Hawks tend to flap their wings, then glide before flapping again. The falcon is much faster and has a constant very rapid wing beat.
Black-backed gull size
Table and information courtesy of the Raptor Association of New Zealand.