Catching up in Mexico

You may remember Matt Prior from our recent Mongolia Diaries series, in which Matt took the Pulsar Axion 2 XG35 to Ugii Lake, ringing wading birds migrating through the area as they made their way to their wintering grounds in south-east Asia, Oceania, and Australia.

Now, we’re catching up with Matt after his latest adventure took him to Komchen Nature Reserve in Yucatán, Mexico. This time, Matt did not manage to take along a thermal imaging device, so we asked him to let us know how he fared with more traditional methods of observation. Read on to find out how he got on.

Day One

I have been at Komchen Nature Reserve in Yucatán for the last few days ringing a variety of resident birds; the highlight so far has been a diminutive but vicious Ferruginous Pygmy Owl closely followed by the bizarre Groove-billed Ani, and, just as we finished our evening meal, one member of our team even took us out to show us a tarantula he had spotted — what an amazing creature it is! Two species of Nightjars have been calling, so I am going out to try to catch some using the hand net and torch. I have not brought the thermal imager this time because I am not sure if there will be enough wildlife for me to see at night in this forest habitat.

Without the thermal imager, I walked along, pointing the torch down the track, looking for the characteristic red-eye reflection that all Nightjar species give. After a few minutes I saw a Nightjar sat on the ground. I approached, but it flew from a long way off.

There are thousands of spiders everywhere I turn out here and they reflected the torchlight, giving me a misleading view that they were the eyes of a bird — I have to learn to ignore these distractions. Not spotting the Nightjars I’d been hearing, I swept the torch around the area and a pair of yellow eyes shone back at me. It was an American Badger — they are rare here and only found in 8 sites in Yucatan — but no sooner than I had spotted it, it was lumbering away.

I also came across a dilapidated building and another sweep with the torch revealed eyes everywhere. I approached a little closer and found a troop of about 20 White-nosed Coatis.

Further along, the track narrowed and the trees were growing low over the track. I had to hold the net very low in front of me, which is a very different style to how I would normally hold it, and I am not confident in this approach. My concern proved to be well-founded because, as I approached another Nightjar, the net snagged up in an overhanging branch and I could not free it before the bird flew off. I must say, I am pretty annoyed by this because, with the low numbers of birds around, opportunities like this will be limited.

On the way back, I caught sight of another red eye, and as I approached my heart was beating half out of my chest with excitement, but I was also nervous, as this could be my only chance. The bird stayed sitting, but it was shuffling and dipping its head, normally a sure sign it will fly away at any moment. I took aim and… phew! The bird was captured.

Close up, Nightjars can be extremely difficult to identify but as I have read the identification book through and through, cover to cover, I knew almost instantly that this bird was a female Pauraque — unsurprising, as the Pauraque is the most common Nightjar of Central America.

I’d been out for a fair while, the temperature had reached 28°C at 10pm, I was sweating profusely, so decided it was high time to call it a night.

Day Two

We’ve enjoyed a good morning ringing Turquoise-browed Motmots, a Buff-bellied Hummingbird that weighs just 3.4g. I’ve been keen to to ring a Hummingbird, so I was watching the process and technique very closely. One of the team came back from a net round and told me that it is my turn, so I took the bird from the bag — it is tiny! A quick read in the ID book confirmed it as a male Ruby-throated Hummingbird. The rings for Hummingbirds are incredibly small and they are cut to size, then shaped in a special tool; the ring is then closed onto the leg with special pliers. I could feel the whole team watching me, but I put them out of mind and focused on the job in hand. This beautiful little bird weighs just 3.3 g, making it the smallest bird that I have ever ringed — I needed all my concentration to be on treating him with the utmost care.

Two hours before dawn I found myself lying uncomfortably in bed in a pool of sweat. As you can imagine, this is about as fun as it sounds, so I decided to get outside and try some dazzling before dawn. The first thing I saw, only metres from the house, was a superb Jaguarundi — a medium-sized cat that is reasonably common, but very hard to see. The woman who runs the nature reserve told me that this Jaguarundi sleeps under some nearby rocks by day.

It is clear there are two species of Nightjar in the area by both call and behaviour. Pauraques come down to sit on the tracks, but they prefer the areas where there is soil, rather than rock. They do not feed along the forest rides, though. They are more jumpy than most Nightjars I have encountered around the world. I did not manage to see the other Nightjars at all because they seemed to be flying high above the trees.

I stopped and briefly recorded their calls using the video recorder on my phone. Then, further along the track, I saw a pair of tiny eyes in a dry-stone wall. The mammal did not like the torchlight and shied away, so I remained still and, after a moment, it came back for another look at me. As it did this, I could just about see enough of it to realise that it was a Southern Spotted Skunk — my first ever skunk!

On the way back to camp, just as dawn was breaking, I came across another Nightjar. This one was not the least bit concerned by my presence — it sat nice and still and its capture was easily made. Continuing back to camp, I could hear Thicket Tinamous but, as is often the case, I was not able to see any of them.

By the time I got back to camp, the other ringers were all up and opening the nets. There are a lot of students here to learn about bird ringing and they all got to see another Pauraque caught in the night. It is an amazing bird, and this one was quite different to the previous Pauraque, with lots of white in the wings and tail, but it soon became clear that, where the previous Pauraque was female, this one was a male.

The morning’s ringing has been quite slow, with a Squirrel Cuckoo avoiding our nets but sitting close by. For North American warblers, however, the morning has been much more productive and I have ringed Northern Parula, Black-throated Green and Myrtle.

And then came another highlight of my time here, as another tiny Hummingbird was brought to me. Taking it out of the bag, it is so light it feels as though I am merely holding an insect, rather than this beautiful little bird. Quite a crowd forms around me, with everyone wanting to take a look at this magnificently tiny creature. It took a few minutes to ID, but we all agreed that this was a Canivets Emerald. I really like the technical detail of ringing these minute birds. The last stage of the process is to weigh it — it is the smallest bird I have ever ringed at just 2.44 g, which is the same weight as the plastic top of a fizzy drink bottle! Joined a little later by a local bird guide, I played the video to him and he confirms that it is a Yucatan Nightjar. He tells me that they never come down to the tracks which confirms my findings.

A Few Days Later

After a few nights’ much needed R&R, I have been back out again, inspired by one of our team who, earlier in the evening, went out and found a scorpion using a UV light torch. Almost straight away I saw a beautiful little Gray Fox. They are similar in size to a domestic cat, and apparently are quite scarce and shy. It did not take kindly to the torchlight and trotted away, sitting down 100 metres away to watch me. I left it alone to observe and carried on in my search for Nightjars.

A Great Horned Owl called out but was nowhere to be seen. A Yucatán Nightjar also called from within the dense thorn scrub and, shining the torch around, I spot a red eye about 30 metres away and around 4 metres off the ground. There was no chance of even getting a good view of this bird and at this point I realised that Yucatan Nightjars are not a possibility — or at least, not at this time of year — and refocused on the Pauraques, of which I did manage to catch a couple.

How Would Thermal Have Helped?

During the two weeks I spent in Yucatán, we managed to ring 8 Pauraques; this is great compared with previous expeditions here, when they have ringed 1-2. It was interesting to compare my experiences and results of using a torch with a thermal camera.

Mammals are clearly disturbed by the torchlight and tend to shy away when the light hits them. If I’d have taken the thermal camera with me, I would have seen the mammals from much further away and would have been able to view them for longer periods and with far less disturbance.

I also wonder what other mammals I would have seen that the torchlight did not pick up. With the thermal camera I would have spotted the Nightjars on the ground much sooner, this would have meant that I could turn the torch on closer to the bird, which would increase the chances of the bird sitting.

The thermal camera would have enabled me to watch the Yucatán Nightjars much better and I could have learned a lot more about their behaviour in this way. Thicket Tinamous are capable of flight but are distantly related to Ostriches and Emus, they are about the size of a partridge, and they are vocal at dawn and dusk, but they are incredibly hard to see; the thermal imager would significantly increase the chances of observing these elusive birds.

Later this year, I have another expedition to a tropical location planned, and this time I will be taking a thermal camera with me. It will be interesting to compare my results from Mexico to what I experience on the next expedition.

Read More:

Keep an eye on the TJ Focus blog over the coming months as we look forward to Matt’s upcoming trip! In the meantime, you can read every installation in his Mongolian Diaries here:

Bird Ringing in Mongolia with Matt Prior: Diaries, Part One

Bird Ringing in Mongolia with Matt Prior: Diaries, Part Two

Bird Ringing in Mongolia with Matt Prior: Diaries, Part Three

All photo credits to Matt Prior.