Nightjars for the Uninitiated

What is a nightjar?

For those of you that have simply stumbled your way here from the great expanses of the internet and are wondering to yourselves "what is a nightjar?" then this is the post for you!

Nightjars are birds in the order Caprimulgiformes and family Caprimulgidae, but if you have little interest in scientific classification, the basic summary is that nightjars are the nocturnal gremlins of the bird world. Various nightjars have earned a smattering of expressive names like liche fowl, 鬼鸟 (ghost bird), cuerporruin (despicable body), and Satanic Nightjar, the latter of which has been attributed to its call sounding like "pulling out a person’s eye". Those names alone are plenty to give you a sense of the spooky and ominous reputations they have in folklore. Having spent as much time as I have with nightjars, I can see why they earned that reputation. 

After all, they stare at you like this:

"Rock Demon," Eastern Whip-poor-will (New York 2023)

Being nocturnal (active primarily at night) or crepuscular (active around dawn and dusk), nightjars have very large eyes for their body size that are very reflective. So large and reflective, in fact, that I used to mistake Common Nighthawks (weight: 65–98 g) for Greater Sage-grouse (weight: 1,800–3,200 g) based on their eyeshine. Looking for eyeshine is one of the easiest ways for us to find nightjars when they aren't singing.

Eastern Whip-poor-will (New York 2024)

Eastern Whip-poor-will eyeshine in the shrubbery (New York 2024)

Now, if you ran into a bird at night, flying around you almost silently with bright, glowing orange eyes, don't you think you might also associate it with ghosts and spirits?

The more you get to know nightjars, however, the weirder and sillier and cooler they are (in my entirely unbiased opinion). Morphologically, they are quite odd. Some of their key characteristics are long wings, short legs, and tiny beaks. Many species have magnificent mustaches (rictal bristles, which are thin sensory feathers around the beak. Like whiskers).

Red-necked Nightjar wing (Spain 2025)

Eastern Whip-poor-will leg (New York 2024) Eastern Whip-poor-will mustache (New York 2024)

Don't let the stubby beak on the ends of their faces deceive you though. It is perhaps the biggest lie of all, since nightjar mouths are absolutely massive.

European Nightjar (Belgium 2025)

Nightjars evolved these traits to be experts at catching insects like moths and beetles. Nightjars catch insects midair while in flight, which is called hawking. Many species, particularly forest species, usually do this by waiting on a perch, sallying out to catch an insect, and returning to the perch. Some nightjars in more open habitats, like Common Nighthawks, usually forage in long continuous flights instead.

The other characteristic that nightjars are rather famous for is being very, very well camouflaged. Almost every nightjar nests on the ground and they often sleep on or near the ground as well. Camouflage is their main defense against predators. Their first instinct is to hold perfectly still when danger is nearby. If you approach too closely, they will fly away suddenly and give you a heart attack if you didn't manage to spot them.

Common Nighthawk (Montana 2022)

Eastern Whip-poor-will (New York 2025)

Unless you are a Kiwi (sorry New Zealand, you have other fun birds) or live in the Arctic/Antarctic, there is a decent chance that there are nightjars somewhere in the vicinity for you to go find (or attempt to find, since success is certainly not guaranteed) depending on the time of year. There are almost 100 different species worldwide!

What is not a nightjar?

Once upon a time, in the dark ages prior to 2021, there was a whole host of other weird nocturnal birds that were lumped into the Caprimulgiformes. These included potoos (Central and South America), frogmouths (Oceania), owlet-nightjars (Oceania), and the one-and-only Oilbird (South America). These "nightjars and allies" were united by camouflaged plumages, cryptic behaviors, short legs, and nocturnal activity. Most of them are also insectivores (if you exclude the Oilbird).

However, after a long and extensive debate over the evolutionary relationships between these groups of birds, the International Ornithological Congress officially split the nightjars and allies into separate taxonomic orders. The chief culprit behind this tragic divorce? Hummingbirds.

The crux of the matter was that, as hard as it is to believe, hummingbirds, swifts, and treeswifts are more closely related to owlet-nightjars than owlet-nightjars are to the other nightjars and allies. In fact, the nightjars are the most distantly related among them.

Here's what their family tree looks like:

Which means that either hummingbirds, swifts, and treeswifts had to join the nightjars and their allies, or the allies had to split from the nightjars, and the latter was usual general consensus. Of course, there's no promise that this won't change again. (This is also why birds are reptiles, because birds are more closely related to crocodilians than crocodilians are to lizards).

That being said, most of us still accept the other weird nocturnal birds as "nightjar allies"! I personally also count hummingbirds, swifts, and treeswifts. The more the merrier! Officially, this group of birds  are Caprimulgimorphae or Strisores. But personally? I like to call them the weird-birds-with-short-legs-that-eat-insects-if-you-ignore-the-oilbird. If you didn't know before, yes, hummingbirds eat insects.