The Family Carnidae is a family consisting of very small flies, most of them between 1 - 2 mm in length. As "Carnidae online" says:
"propably due to their small size, they have not attracted a great degree of study"
This means that the Family Carnidae is not very well known. An exception to this is a parasitic species of Carnidae that targets birds, and as you can imagine, there were quite a few studies carried out on that particular species.
Carnidae, also known as Bird flies or Filth flies, is a family of flies (Diptera). There are 6 genera, containing about 93 species worldwide.
Most of the species are very small at 1–2 mm.