You might not be able to spot the nightjar, but you can hear it

May 26, 2014 • 9:26 am

by Matthew Cobb

I used to run a field course for second-year university students at Saint-Auban in the foothills of the French Alps. My favourite bit of the course was when we would drive out at dusk into a deserted valley (seen in the picture below, taken from a nearby peak) and observe the local animals as they emerged from the forest. We would regularly see lowland hare, fox, roe deer and, if we were very lucky, wild boar.

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In the parts of the valley that are dominated by heathland, out of sight on the photo, we would encounter the eerie nightjar. Often, the first sight of this amazing bird would generally be the gleam of its red eye, reflected in the car headlights. For reasons that I don’t think anyone understands, nightjars tend to sit in the middle of the road, playing chicken with any oncoming car. Maybe they are warming themselves on the tarmac, and as a nocturnal/crepuscular bird they are blinded by the headlights and just sit tight until the last possible moment.

The male nightjar will perch on a branch – often in a pine tree – and sing, a bizarre churring sound that, once heard, is never forgotten. Why they sing like this is not clear, but it carries long distances and also spreads in all directions – it is often very difficult to localise. This would be advantageous both for attracting a mate and for territorial purposes – the latter seems particularly important in nightjars.

I presume the  structure of the song is related to the geography of the heathland where they live, with lower wavelengths travelling further and not being absorbed by dense woodland. There may also be an element to the song which encodes the male’s fitness in some way.

In Asian nightjars, the song seems to be a defining feature of the species and is a reliable way of differentiating otherwise similar species, as shown in this 2008 article, which includes the identification of a new species, partly on the basis of its song. It turns out that you can reliably identify individual birds on the basis of their song.

This French video shows you what the song is like. In French, the nightjar is l’engoulevent (the wind-swallower). You’ll notice that it carries on singing for ages – it seems to be able to do this by singing as it is inhaling as well as when it exhales.

Now this site’s favourite cryptic bird has received the ultimate accolade – it has been featured on BBC Radio 4’s excellent series, Tweet of the Day, which we have mentioned here before. This is a 2-minute daily radio slot featuring birds from the UK, with their song and some brief details about their ecology. I can’t embed the programme, so you’ll have to click on this link to listen on the BBC site (a screenshot is below).

Go ahead – you’ll learn some stuff, and the sound will transport you to warm summer nights in France, and the sounds and smells of the mountains.

Totd

 

11 thoughts on “You might not be able to spot the nightjar, but you can hear it

  1. We would regularly see lowland hare, fox, roe deer and, if we were very lucky, wild boar.

    I have a friend outside Asheville NC who will consider himself very lucky if he never sees a wild boar again ever. He recently brought one down that topped his scale out at over 440lbs. They’re incompatible with the backcross American Chestnuts he’s trying to grow.

  2. A couple of weeks ago, we had a four-nightjar evening at Madera Canyon in the Santa Rita Mountains. We heard the Mexican whip-poor-will, poorwill, lesser nighthawk, and the bird we had come for: the cookachea or buff-collared nightjar. Other night voices included the whiskered screech owl, elf owl, and a noisy gang of Gould’s turkeys.

    I had never heard the Mexican whip-poor-will (recently promoted to species status; it was formerly considered a subspecies of the eastern whip-poor-will). The calls are different: the Mexican species is quieter but more varied in pitch and speed.

    Lesser nighthawks are nesting on the bajada ridges in the desert near our house, and hawking for insects over our yard in the evening. Their churring trills come from everywhere at once, often seeming to rise out of the ground.

    1. That sounds transporting! I love listening to the wild at night! (Though our coyotes are getting out of hand…)

    2. Congratulations! I still haven’t ever heard the Buff-collared Nightjar in Arizona, sad to say.

  3. It occurs to me that the Jurassic must have been a very noisy era, considering how vocal its survivors are.

    Has there been any research into the evolution of birdsong? Not of its initial origins, but more of a etymological study, comparing songs and relatedness across species? Are there any common roots that might point to what some ancestral songs might have sounded like?

    b&

    1. Short answer re “Has there been any research…?” – Yes, lots (IGIFY). Only a certain proportion of papers are freely accessible online, but still plenty. Many of the studies are focused on groups of closely related species, because it’s hard to identify homologies in song structure across wider groups. One of the major groups of passerines, called oscines (as opposed to suboscines), are distinguished by having to learn their songs from conspecifics, so there’s lots of scope for developmental studies and experimental manipulation.

  4. Re: birds singing while inhaling. Birds have an unique respiratory system, where the air passes through the lungs in one direction. Airflow is regulated by air-sacs. Think of bagpipes, where the sound is continuous even when the piper is inhaling.

    1. Some flautists and all serious didgeridoo players practice ‘circular breathing’, described as a technique that enables the wind instrumentalist to maintain a sound for long periods of time by inhaling through the nose while maintaining airflow through the instrument, using the cheeks as bellows.
      Moreover, the ‘unique’ unidirectional airflow in bird lungs is not so unique anymore. In the last few years, functionally unidirectional flow through the lungs (without such well-developed airsacs, so less obvious anatomically) has been demonstrated in crocodilians (here and here) and some lizards (e.g. here).

  5. My cat also makes a raspy sound which continues as she inhales and exhales. This saves me from having to travel to France and stay up late at night to enjoy it.

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