To begin, I’ll back track: I believe that a species of modern pterosaur could be diurnal but it would be likely a rare species living in a remote area. It would be an exception.
The general rule points to nocturnal pterosaurs, with daylight sightings being quite likely the exceptions. We might review the two daylight sightings in Georgia a few years ago. The eyewitness saw two apparent pterosaurs flying early in the morning, but after sunrise, the first sighting being very soon after a major storm passed through that part of the United States. It seems likely that the storm had disturbed two nocturnal pterosaurs enough that they made themselves known in daylight, by flying over a highway.
To review what these sightings entailed, the lady saw two different flying creatures, two weeks apart, late in the summer of 2008. They were obviously of the same species but different sizes. The tail was long, with a “heart” shape at tail-end. Even the smaller one was larger than any ordinary bird. The wing flapping especially caught her attention, for it was different than anything she had ever seen in the flapping of bird wings: “The wings ‘pumped’ in a ‘scooping’ manner, as the motion rippled along the body and through the tail.
Perhaps the most significant evidence for the general rule that modern pterosaurs are nocturnal is the connection with bioluminescence. Many of the repeated-sighting areas are where flying lights are observed, for example, in Papua New Guinea. But strange flying lights at night are also seen in North America, including Texas.
Could Marfa Lights be nocturnal flying scavengers? I don’t mean to put down the bat hunting hypothesis, regarding the splittings and rejoinings that may have given rise to the comment from residents about “dancing devils.” That may have a place, during seasons when bats are about around Marfa, Texas . . . But bats are unlikely to be about during the colder winter nights, and some of the stranger Marfa Lights are seen on some of those nights.
Since the kongamato of Africa and the ropen of Papua New Guinea are known to scavenge at least on some nights, according to some reports, similar modern pterosaurs could do the same in North America.
One night, whilst sitting on the ground by the tents . . . I saw what I at first assumed was an owl gliding over the campsite (I assumed that because it was night time, and obviously no other birds would be out-bar things like nightjars-which this was not!) – it passed right over us, probably about 30-40ft high, and as I watched it, I realised it was definitely no owl I’d ever seen before. It was the colour of suede/sand, looked like the same sort of texture as suede (i.e no feathers), had a long thin tail, and didn’t flap once.