Three times in 12 years Emerald Forest Doves have mistaken our windows as extensions of their forest habitat and have paid the price. Yesterday one bird met its fate. When I picked it up I noticed a very large (relative to the size of the bird) Louse Fly. I have written about these flies before when they showed up at the light sheet. Louse Flies are external parasites of birds and mammals in the family Hippoboscidae. You can get an idea of the diversity of the family from the images on the site.
Louse flies are remarkably adapted for existence in bird feathers. Some species detach their wings when they have found the proper host. Eggs mature within the mothers and the living larvae are deposited away from the host and they have to undergo the lottery that many parasites are forced to endure. The right host has to come along at the right time for the larvae to continue their development.
The flattened appearance of the adult likens them to lice, hence the common name. Several are parasites of livestock and are transported around the world on their hosts. Australia has several introduced species that are just such pests.
But nothing is straight-forward in this world. The odd creature below was also found within the feathers of the poor bird.
Along related lines, have a look at Piotr's blog on another, much more robust, parasitic fly.