Mystery Bird: Lesser Nighthawk, Chordeiles acutipennis

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[Mystery bird] Lesser Nighthawk, Chordeiles acutipennis, photographed at Desert Botanical Gardens, Phoenix, Arizona. [I will identify this bird for you tomorrow]
Image: Richard Ditch, 2005 [larger view].

Date Time Original: 2005:07:12 07:24:54
Exposure Time: 1/60
F-Number: 16.00
ISO: 200


Rick Wright, Managing Director of WINGS Birding Tours Worldwide, writes:
Cryptic of plumage, large of eye, tiny of bill, this can only be a nightjar. The folded wingtip reaches more or less to the tip of the tail — hard to know exactly from this angle — and that makes this bird a nighthawk.
The non-echoic names for members of the order Caprimulgiformes are pretty fascinating. The order, family, and nominate genus names all refer to the ancient but rather fishy story that rural folk in Greece suspected these odd creatures with their frighteningly wide gapes of stealing milk from goats at night; it’s unlikely that anyone ever actually believed this story, which is more likely a literary fiction than an ethnological transcription. The English word “goatsucker,” “goatmilker,” a direct translation of the scientific name Caprimulgus, has largely been replaced over the last couple of decades by the less scurrilous but equally evocative “nightjar,” a name that refers to the churring song of the widespread European species.
Most American species in the family have onomatopoetic names, attempts to capture in English syllables the nocturnal chants these birds are famous for. That wouldn’t work very well for the two North American nighthawk species, though; any sort of mimicry of the sounds produced by Common Nighthawk will get you thrown out of polite society, while the attempt to replicate the long screech-owl like trill of a Lesser will get you thrown into a place where people speak soothingly and the windows are locked.
Apart from their voices, the two North American species of Chordeiles nighthawks are pretty similar to each other. They differ most famously in wing structure, the long outermost primary of Common Nighthawk giving that species a sharply pointed wing, while the corresponding feather of Lesser Nighthawk is responsible for that species’ typical blunt-winged appearance. On my computer screen at least, our mystery bird seems to have one blunt wing — the right one — and one more acutely pointed on — the left one.
More useful — and note that we’re staying at the rear of the bird — is the pattern of the folded primaries. On Common (and on Antillean) Nighthawk, those feathers are solid dull black, with a single large white blotch that contributes to the striking primary bar shown by this species in flight. In Lesser Nighthawk, in addition to a whitish or buffy blotch, there is a regular pattern of small yellowish bars or spots anterior to the larger blotch. Such markings are easily visible on this bird, a female Lesser Nighthawk.
An additional and startlingly helpful mark for telling these two apart in late summer is their different molt schedules: adult Lesser Nighthawks molt wing feathers before the southward migration, while Commons — far the longer-distance migrants — wait until they have arrived on the wintering grounds. This is described in the best new field guides, and even the most blurred of photos can show the difference.
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About GrrlScientist

grrlscientist is the pseudonym of an evolutionary biologist and ornithologist who writes about evolution, ethology, and ecology, especially in birds. After earning a degree in microbiology (thesis focus: virology) and working at the Fred Hutchinson Cancer Research Center in Seattle, she earned her PhD in zoology from the University of Washington in Seattle, where she studied the molecular correlates of testosterone and behaviour in white-crowned sparrows. She then worked a Chapman Postdoctoral Fellow at the American Museum of Natural History in New York City, where she studied the speciation and distribution of lories and other parrots throughout the South Pacific Islands. A discarded scientist, she returned to her roots: writing. Formerly hosted by The Guardian (UK), she now writes about science for Forbes and for the non-profit think tank, the Evolution Institute and she writes podcasts for BirdNote Radio. An avid lifelong birder and aviculturist, she lives with a flock of songbirds and parrots somewhere in Germany.
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0 Responses to Mystery Bird: Lesser Nighthawk, Chordeiles acutipennis

  1. Bob O'H says:

    You have nightjars over there?
    Ah, OK. You think jars are hawks. OK, I’ll sit back and watch you all argue about what species it is.

  2. ratporchrico says:

    Definitely a Nightjar for my money – didn’t know about the transatlantic disagreements though.

  3. aedis says:

    Can’t see a collar, so its a nightjar for me, too.
    Tail looks brown too – probably a female. (Adult male has white tail tips, First-summer male has buff tail tips.)

  4. The Ridger says:

    I don’t know what kind of nightjar, but that’s what it is.

  5. After some time with Sibley, I think this is a lesser nighthawk. Things that pushed me in that direction are 1) the white feather at the lower-front edge of the folded wing, which says “nighthawk”, and 2) the prominent buffy spots on the primaries, which say “lesser”.

  6. lars says:

    Lesser nighthawk
    😉

  7. Fia says:

    I don’t know nothing about how to distinguish nightjars by sight, but this is a very nice photo!

  8. RM says:

    goatsucker

  9. Hilary says:

    Probably a Lesser Nighthawk (which I’ve never had the good fortune to see) as it looks like the wings are no longer than the tail, and may be shorter. The under-beak area looks light colored, though, and all the pictures of birds in this family seem to be dark there….

  10. JohnB says:

    a lesser goatsucking nightjar…nighthawk type bird.

  11. JohnB says:

    on second glance I noticed a little ball of fluff underneath her. A brooding female!

  12. John Del Rio says:

    I believe it to be a Lesser Nightjar.
    I love seeing these guys flying by at night. Their call is startling if you don’t see them coming.
    John

  13. oooo, good eye, JohnB!

  14. okay, this is for those of you who have identified this bird: what led you to identify this bird the way you did? was it a field mark? if so, tell us what that (those) field mark(s) are .. if you found reference to a particular field mark in a field guide, tell us which field guide you are using (since most of them differ! this will provide an interesting “real life” comparison between field guides, too).
    thanks.

  15. Definitely one of the goatsuckers: whippoorwill, nighthawk, poor-will, etc. I seldom see nighthawks, but hear them overhead at night. Actually, nightjar is probably a much better name because they aren’t hawks and their call is a ‘jrrrr’ sound.

  16. Monado says:

    Amaaazing camouflage, big mouth, general shape.

  17. Bob O'H says:

    Oh dear, one of this bird’s cousins made it into the (Manchester) Guardian on Friday

    It flew 3,000 miles across the Atlantic, surviving all that an ocean storm could send its way, and was entitled to a bit of relaxation, a hearty meal of insects and the adoration of birdwatchers. This, after all, is a bird with a rarity value described by one website as “mega”.
    But sadly for this hardy common nighthawk – common, that is, in the US, – its odyssey ended abruptly and violently when it was hit by a car shortly after touching down on the Isles of Scilly.

  18. bobk says:

    Lesser Nighthawk.
    The long body, well defined neck and prominent white feather at the leading edge of the “shoulder” make this a Nighthawk. The nightjars are sort of short and plump with no neck to speak of.
    I can also see all the field marks Sibley points out in comparing the Lesser with the Common:
    The tail extends to the tip of the primaries. The edge of the wing bar can be seen just under the back edge of the tertial feathers rather than farther forward as on the Common. The buffy spots on the primaries can be seen under the tertials. And, most subtle, the lack of black patches on the more uniformly sandy back.
    I think the best field mark would be the long tail. The other features are probably too subtle to be picked up through binoculars at any distance. And that just begs the question – how was a bird so perfectly camouflaged spotted to begin with? I would think one must know of a nesting area beforehand which could be checked out closely.
    In this case, Sibley which shows the plumages of the juvenile, female and male is clearly superior to Peterson which just shows the male and barely that for the Lesser.
    However I don’t have one of the better photo field guides for comparison. Photos can be better at showing things of general impression such as overall cast or brightness of color. And as much as I appreciate the beauty of drawings, they tend to leave out the surroundings – the habitat and foliage the bird is typically found in. As an example, look at how well this bird in this photo matches its background. I think the next revolution in field guides will be the inclusion of these background features.

  19. Susan says:

    A nighthawk flew into my bedroom last night, 40 miles down the Baja coast from the border.
    I PUT IT INTO A BOX AND PHOTOGRAPHED IT THIS MORNING THEN LET IT GO.
    These things puff up and hiss! very interesting…if i can figure out how to down load the photo, I would enjoy some input as to which kind it is….buff brown splochy dark spots white band on the tail…can’t believe how big it’s eyes are……all the better to see with when one is a nighthawk.

  20. Susan says:

    Yes, and by the way it has a white area under its chin, and light almost stripes on it’s head……is it a lesser? hmmmm? it’s head seems huge, but maybe thats all feathers

  21. “And that just begs the question – how was a bird so perfectly camouflaged spotted to begin with? I would think one must know of a nesting area beforehand which could be checked out closely.”
    This image was made at the Desert Botanical Gardens (where my wife was a volunteer) a few miles east of Sky Harbor Airport in Phoenix, AZ. It was discovered along one of the public trails by a group led by a docent pointing out the various cacti. The docent was happy to point it out to me the next day.
    I returned early the following morning and went directly to the spot. It took a lot of looking to detect the bird less than two feet from where it had been the following day.
    I was able to sit down with my gear about 10 feet away on an assortment of rocks and cactus spines and watch the bird for 90 minutes. The bird showed no signs of agitation, and I was able to take many images with my 300mm lens and a 1.4x converter. This is a full frame shot – no cropping.
    I didn’t know the bird had chicks until it shifted about revealing two of them. After 30-45 minutes the adult stood up and ambled a foot or so into a more shaded spot, leaving both chicks completely exposed in front of me. A couple minutes later the chicks moved over as well.
    It was an incredible experience for me!