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Nightjar

Shape Conforming

I hope you’re not getting tired of hearing about Nightjar but honestly I don’t care haha. Spending time with one species, learning more about their characteristics and behaviour is what I love and it’s the only way you’ll ever get a chance of photographing this species in the day. I’m now on my 4th pair and my 7th individual (yet to locate the female of the 4th pair). I find it interesting that each pair has chosen a different type of habitat, or at-least the same habitat at different stages.

  1. 3-4 Year Old clear-fell, mostly small-medium sized trees

  2. 1 year old clear-fell, only bracken, grass.

  3. 3 year old clear-fell, mostly grassland, bracken and heath

  4. 3 year old clear-fell, totally rocky habitat with bracken between.

It goes to show how versatile they are, so long as there is suitable habitat around them for moths, they’ll roost almost anywhere there’s suitable cover.
The pair that’s chosen the rocky habitat is the one that I’m most interested in, as he’s also choosing to roost on rocks, rather than logs/sticks. If you look closely, even the shape of his back appears to match the shape of the rock. I wonder if this is strategic? Shape conforming is common amongst species that rely on camouflage to survive and they do appear to match their chosen roost spot. If on the end of a log, they’ll sit tall, short, tail town as if they’re part of the end of that log. If they sit across a stick, they’ll sit in the same direction and flatten themselves out.

As a contrast, here’s the female of pair number 3 showing that typical flattened out pose that matches the long shape of a stick. I loved this chosen roost spot, but it’s doubtful she’ll use it again though as she looks ready to burst. I’m surprised she hasn’t laid yet. Maybe she has and her first clutch failed? I hope that isn’t the case.


I’ve also been studying their vocalisations but I’ve needed a few years worth of field recordings on Nightjar, in order to confirm a theory that you can identify individual males by their song. The way you would do this is to work out the average BPM, length of phrases and also the frequency of both exhale and inhale.
I’ve collected so far at-least 6 different males, though I’ve focused on returning to the same territory for the last 2 years in the hope to confirm it with one individual male. So far it looks like I can confirm this theory, as I’m finding only a 0.8 difference between the BPM recorded in 2017 to present day. A couple more years worth of recording Males and I should be able to give more weight to this theory.
The analysis is actually pretty easy and could even be done in the field so long as you had a laptop to return to. I’ll publish more details about my methods at the end of the season.

Nightjar Identification

Nightjar and Firecrest Progress

Despite having a tough year so far, both financially and with my health, I still feel privileged to spend my free time with nature, and even more privileged to spend most of that time with Firecrests and Nightjar this season. I started the season collecting Firecrest recordings as I wanted to learn more about their mimicking behaviour. There are still many unanswered questions but I’ll update on this soon.

I’ve since got a little distracted, as Nightjar season has well and truly started. It’s almost a full time Job to keep track of the birds roosting patterns. You’ve got to be extremely cautious and committed to find roosting nightjar. Cautious because you don’t want to cause any disturbance, especially now in breeding season but also because they will inevitably see you long before you see them and flushing them is simply not an option if you wish to ever see them again. It’s a huge trust exercise and they need to learn that you are not a threat, so trampling thru breeding habitat hoping to find one is asking for problems. It’s knowing where they won’t be rather than knowing exactly where they are. I’m so glad I read up on these birds and took some great advice off experts as the last thing I would want is for my presence to have a negative impact on their breeding success. As a result I’ve witnessed some fabulous behaviour and characteristics of individual birds.

Meet Blackbeard, The male from pair no1. He prefers to roost in dense cover and as a result I’ve decided to leave him alone this season as there’s no way of approaching him silently. I’ve called him Blackbeard as he’s considerably darker than all my other Nightjars. Not just his throat, but the stripe down his breast, around his lower eye and also down his back is quite dark. He’s generally more rufous with a wider range of colours.

Blackbeard (Male no1)

Blackbeard (Male no1)

This is his current Female that I’ve named ‘bark’ as she prefers tree stumps and has consistent colouration from head to tail like tree bark without any lichen. Not a very feminine name I know but it’s descriptive enough for me to ID in the field. She was my first ever self found Nightjar. She’s now sitting on eggs but is also in deep cover so this pair I tend to enjoy watching at night only, from a vantage point, rather than pursue them in the day time and possibly cause disturbance.

Female no1

The second pair is a complete different ball-game, and are much easier to approach without making too much noise. They’re both roosting close to the ground but he likes logs or even plastic tree guards. She’s about 10 meters away in a small ditch and is now also sitting on two eggs. I’ve named male no2 silverback due to his overall light shade of grey. He was proving to be quite an attentive partner but since we’ve been having heavy rain, he’s taken to a more sheltered part of the forestry 60+ meters away which is very dry. Do you blame him? I don’t. The female however has no choice but to endure the elements till nightfall where the male then brings her food or they’ll swap over so she can feed. I do wonder if Silverback has gone off with another female while she’s been sat on the eggs as there is a female even closer to his current dry roost that’s been landing on the path and wagging her tail in front of him. He has shown interest in her so it wouldn’t surprise me if he did copulate with her too, this is common with Nightjars. Once his original female has hatched her eggs however, he should take over parental duties when the chicks are large enough, at which point he will copulate with her again, and she’ll lay a second brood elsewhere. The saying, ‘don’t put all your eggs in one basket’ is a literal strategy for these birds and in doing this, they increase their chances of survival, even if only one chick manages to fledge.

This pair is a reminder that they’re so vulnerable to predators on the ground, whether it’s snakes, other birds, deer, badgers, foxes, mice, PEOPLE.. there’s so much out there that seek to kill them, which is why they invest so much (or so little) energy into keeping up their ‘log’ act. It’s vital they aren’t seen moving in the day time. Not so easy when you’re soaking wet and cold, or boiling hot in the sun with insects crawling over you.

Below is female no2 which I’m now going to call ‘lichen’ as the contrast of her dark shoulder really makes the lighter wing strips stand out, like a patch of lichen on a branch. She also has quite short wings and a more rounded shorter head than the Male who has a long, flat head shape. Their shape does vary as they manipulate their plumage in different positions but these features are generally unmistakable in the field once you’ve spent some time with them. This is her below sitting on the eggs, it’s a cropped image and from quite far off as I’d rather not disturb her.

Lichen Nightjar Female Sitting

This next bit might make some laugh, but I certainly didn’t find it funny at the time, but a group of young irresponsible adults bumped into me one night while recording Nightjar at dusk. They didn’t bother me at first and showed very little interest in what I was doing but they did turn the music up louder in their car to annoy me. What they did next though questions their insanity.., as they must have drove all the way home, picked up a family members wind instrument (possibly trumpet), with the intent on coming back up the mountain so they could destroy any chance of me getting clean recordings. Take a listen below, you couldn’t have made this up honestly.. Skip to the end..It’s actually hilarious the more I think about it. I just can’t believe the measures some people are willing to take to disrupt other peoples lives.

Between the trumpets, I was watching quite a few bats on the wing while watching the Nightjar and all I could hear thru my headphones were the faint sound of beating wings. I did wonder if my Telinga Microphone could actually pick up such high frequencies and it turns out, IT CAN! After slowing my recording down in Logic Pro X, I was able to pick out each ‘tweet’ that the bats were producing. These tweets are not audible without slowing the recording down but i’m amazed how much detail I was able to capture. It makes me wonder how many bats are in my previous recordings and the only way of telling would be to lower the pitch or slow the recordings down. I’ve always wanted to record bat sound but always thought I would need a Bat detector to do so.

I do have 3 other pairs of Nightjar that I know roughly where they’re roosting but you need to spend weeks observing them before considering yomping thru their habitat. Please be responsible, all breeding birds are protected and I would not be pursuing them if I wasn’t 100% sure I could do so without disturbance.