Caprimulgiformes is a taxonomic order that is used to classify birds. Organisms are classified because of their similarities and differences and the term order is just one out of the seven taxonomic units or ranks that is used in classification. Other units include the kingdom which is the most general is the kingdom while the most specific is the species. Other units in between are phylum, class, family and genus

The order Caprimulgiformes is a taxonomic rank that brings together a number of birds that are distributed everywhere in the globe with an exception of Antarctica. This group of birds mainly comprises the avian types that are insectivorous or nocturnal. Insectivorous simply mean they depend on insects as their primary source of food while nocturnal means they are active at night and sleep during the day. The order Caprimulgiformes derives its name from a Latin word which loosely translates to ‘goat-sucker.’

The birds making this order and which are mainly nocturnal hunters are known to possess a highly advanced sense of sight just like the owls. They are also very good flyers and to support this, they have weak legs which are very small. Because of the facts that they shared a lot of characteristics with birds like owl, hornbill, swifts, rollers, and hoopoes, they were at one time associated with one another by scientists.

Evolution
Based on the records provided by the fossils – the remains of animal and pant organisms from the past-does not suggest a lot. However, it provides enough evidence about the emerging phylogeny well. Though somewhat uncertain, the evidence adduced from the fossil records tends to suggest that this order might have evolved from the genus Paraprefica. This is based o n the fact that at one time in their evolutionary stage, they may have been associated with the oilbird and potoos, although it cannot be assigned in the genus of either of theses birds with confidence. Thus, as scientists unanimously agree, this would present a divergence of three different lineages. This is in total concurrence with the fossil records which suggest that the divergence of the bird called nightjar and another one called apodiform branch may have also occurred during that time. Another fact which tends to support this view is that Eocypselus, which is a genus that mostly inhabits the north-central Europe, cannot be put into any of the cypselomorph lineages with confidence although it appears like an ancestral form of it..

There have been frantic efforts in the Caprimulgiformes order to investigate the monopholy of the order and the phylogeny in their traditional families. In this order, owlet nightjars are seen to have close resemblance to swifts and hummingbirds and therefore they are sister groups with Apordiformes. There was no evidence to back the fact that the monopholy of a clade comprising of Caprimulgiformes.

In the Caprimulgidae order, the Australasian genus was found to be sister to the other family members. Many species in this order have both elevated heterozygnosity and GC3 content, which is a fact that serves to show that they are closely related.