I spent most of today with a fly. That may seem like a huge waste of time, but this was no ordinary fly – it was a wallaby fly. The closest I usually get to one of these flies is when I see a wallaby in the garden furiously flicking its ears trying to dislodge one. The individual here took a liking to me in the garden, and hitched a ride inside.
Flies of the family Hippoboscidae are all blood-sucking ectoparasites, i.e. parasites that live on the outside of their hosts. These flies usually cling to the hair of mammals or feathers of birds depending on the fly species involved. They have characteristically flattened bodies, powerful legs, and fishhook-like claws (clearly visible in the image below). You can see now why they are known generally as ‘louse flies’. There are more than 200 species found throughout the world (30 species here), and about 75% of them are ectoparasites of birds.