Readers’ wildlife photos

May 9, 2023 • 8:15 am

Today we have a lovely selection of photos of red-eyed frogs taken by reader Mike Canzoneri.  His notes are indented, and you can enlarge the photos by clicking on them.

The Red-Eyed Tree Frog (Agalychnis callidryas) is probably the most photographed frog in the world, and it’s not difficult to see why. These colorful frogs have a unique personality and are incredibly photogenic.

The Red-Eyed Tree Frogs shown here are all from my property on the Southern Pacific coast of Costa Rica and are less colorful than the populations found on Costa Rica’s Caribbean coast. In fact, the coloration varies significantly from one isolated population to the next, and this year we are likely going to see the species get reclassified and split up into several separate species based on geographic population throughout its range. The color morph that I have around me lacks the vivid blue bars on the side of the body (mine are more bluish-gray) and the bright yellow/orange on the legs and feet that you find on the population on the Caribbean coast. A large percentage of the ones I see also have one or more white spots on their backs as can be seen in the 1st photo below.

Since moving to my house and rain forest property in the Golfito area, I’ve watched the A. callidryas population increase, though not nearly as sharply as some other frog species around me. The main reason for this is that I started keeping the lagoon in front of my house filled with water through the dry season (it normally dries up after the rains stop and rainy season ends) and I’ve added several more year-round tanks of water. Not only do the late rainy season tadpoles now make it to the frog phase, but reproduction for many species continues year-round around my house. Below is a common sight (A. callidryas in amplexus) on practically any night around the lagoon and tanks. After a pair spends time in amplexus they will eventually move to the underside of a large leaf over-hanging some water to deposit and fertilize eggs in a golf ball sized gelatinous egg mass. When the eggs hatch, 7 to 10 days later, the new-born tadpoles drop into the water below.

With an increased population of A. callidryas, I’ve also seen an increase in the populations of their predators, most notably the Northern Cat-Eyed snake (Leptodeira septentrionalis), which feeds on frog egg masses (primarily those of A. callidryas) and also on the frogs themselves (any species they can fit in their mouth) and even tadpoles. Here I noticed a Red-Eyed Tree Frog on the same leaf as a Northern Cat-Eyed snake. The snake eventually moved on and the frog was unharmed.

An interesting sight I caught a couple weeks ago was two male A. callidryas fighting, likely over territory. I had never seen this behavior before from this species (plenty of other species show aggression between males) and it was surprising because these guys are typically low-energy frogs and at night you frequently see them sleeping, even the males during mating. These two were wrestling on a leaf and when the one on the bottom rolled over to the top, they both rolled off the leaf…at the last instant, the feet of one of them caught the base of the leaf and they hung, upside-down, still grappling. Eventually they separated and both climbed back onto the leaf.

And finally, here are some sleepy Red-Eyed Tree Frogs. Notice the gold nictitating membrane that covers each of their eyes…it obscures the bright red eyes that could catch the eyes of a predator while still allowing the frog to see what is going on around it.

If you found this interesting and enjoyed the photos, I can do another piece on some of the other frog species that inhabit the same environment around my house. Feel free to ask me anything about any of these photos or about the frogs around me in Costa Rica. For the photographers: all of these shots were taken at night, in-situ, with a Lumix (Panasonic) G9 20MP Micro 4/3 camera and an Olympus 12-40mm f/2.8 zoom lens and with a Godox V860ii speedlight mounted on the camera and a custom flash diffuser made by Erick Mesen here in Costa Rica.

I want to see more frogs, so please urge Mike to send more photos!

30 thoughts on “Readers’ wildlife photos

    1. Hey Janet….I think the bright red eyes (and the bright orange coloration found on the feet and legs of the Caribbean morphs) are likely an evolutionary attempt at mimickry to seem more toxic than they really are to the average predator. But the bright red eyes also make A. callidryas easy to spot for the predators that feed on them and I think that’s why they developed the gold nictitating membrane that mutes the red but still allows them to see.

  1. Wow, what gorgeous critters! Yes, please do send more frog photos, Mike. These ones are amazing.

      1. Evenings provide some of the best photographic backdrops, and you’ve taken good advantage of these well-lighted subjects with black(ish) backgrounds. Kudos. Striking photography.

  2. “gold nictitating membrane”

    Yes – that! Astonishing!

    What a surprise, delightful little set!

  3. Lovely photos, and thank you for making the effort to keep your pond full year around. Please send more photos and share your knowledge of these fascinating creatures.

    1. Keeping the lagoon/pond wet through the dry season, adding some 2m X 1m concrete tanks and some bisected plastic 55 gallon drums has gone a long way to increasing the frog population around my place. The Masked Tree Frogs (Smilisca phaeota) really exploited the available water this last dry season and I’ve raised up 10s of thousands of them to little froglets in the last 6 months or so. I also keep them fed and I rescue eggs of the leaf laying species when they are not directly over water. I basically have a frog factory….with the global decline in amphibian populations over the last several decades, I don’t feel bad about doing this. I’m in the process of putting another permanent, large concrete tank in place. I’m seeing new species (for me) around the house every year and my goal is to get as much biodiversity as possible there and then watch it all radiate out into the forest.

  4. Very nicely done, with great details in the narrative. I also very much enjoyed studying the face of your very good diffuser in the eye reflections.
    More froggies, please!

    1. Thank you, Mark….I’m still finding my way with the set up after doing all my “frogtography” in my studio with 400w strobes and huge soft boxes and full frame Nikon gear with the 105mm Micro Nikkor glass. There’s just something more satisfying about getting these shots in-situ.

  5. I am not sure what’s happening in the fourth and last pix (I have a guess), but I love how the bottom frogs pupils are so dilated.

  6. Yes, excellent set, and I too want to see more!!! I used to be a resident guide at Marenco Biological Station near you, but I never saw this species. There were no ponds because the terrain there is a bit hilly. I suppose that’s why I never saw any.

    Your photos of the fight between two males are exceptionally interesting. The chances of seeing that seem very low. You are tremendously lucky to be living there. Congratulations on your life choices.

    I spent time on the Caribbean side of CR too, where I saw the other version of A. callidryas. People can see my pictures here (note the the bright orange extremities)::

    One thing I learned about them is that they change color rapidly depending on mood, almost like cuttlefish! Do yours do that? I would suppose so, since I saw the same changes in other Agalychnis species.. One species, Agalychnis saltator, changed from green to brown, as seen here:

    1. Great stuff, Lou. The color change on A. saltator is dramatic. I see only color changes in the hue of green on the bodies of A. callidryas.

      Do you get down to CR any more?

      1. Hi Mike, no, for me CR is now “up” rather than “down”, as I live and work in Ecuador. It’s been many years since I went back to CR, though I love that country very much.

  7. I’ll add to the chorus; please post more frog photos! Many thanks for these. I wonder how much of that species splitting based on regional colorations is legitimate. I would have thought likely that most are variants of the same species. How does one distinguish those variuant populations from populations that really are different species?

    1. Thanks, Edward. I wondered the same thing about the splitting of callidryas. I’ve talked with a few herpetologists here in Costa Rica who are confident that it will happen, and probably this year. I have to believe they are going on more than just color morphology but I don’t know the specifics yet.

  8. These photos are phenomenal. I’m so sorry to respond so late.
    Please send more photos. This is a great post.

  9. Yes, more please. Thanks for the exquisite photos and informative commentary. Beautiful frogs, I must say, so many nice expressions. All life is special and meaningful, humans don’t have a monopoly on that. Hopefully we’ll see more of your wonderful photos soon.

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