Frog Blog

Costa Rica 2025


Ghost Glass Frog (Sachatamia ilex) near Siquirres, Costa Rica

I spent 7 days in Costa Rica this August. Unlike previous trips to CR, this was a frog recording trip. My previous trips have all been birding trips where I got a chance to do a few minutes or recording along the way. This trip was planned as a frog recording trip with a bit of butterfly watching/photography in the intervening waking hours.

So for that reason, I recorded quite a few species of frogs (~22) including the following new ones (I will provide links to the new blog pages as I make them):

San Carlos Treefrog (Dendropsophus phlebodes)
Blue-sided Leaf Frog (Agalychnis annae)
Parachuting Red-eyed Leaf Frog (Agalychnis saltator)
Lemur Leaf Frog (Agalychnis lemur)
Gliding Leaf Frog (Agalychnis spurrelli)
Mahogany Treefrog (Tlalocohyla loquax)
Dwarf Glassfrog (Teratohyla spinosa)
Ghost Glassfrog (Sachatamia ilex)

Of course, I ran across some old friends as well and was happy to record these species again!

Red-eyed Leaf Frog (Agalychnis callidryas)
Boulenger's Snouted Treefrog (Scinax boulengeri)
Snouted Treefrog (Scinax elaeochora)
Hourglass Treefrog (Dendropsophus ebraccatus)
Yellow Treefrog (Dendropsophus microcephalus)
Northern Smokey Jungle Frog (Leptodactylus savagei)
Sabinal Frog (Leptodactylus melanonotus)
Mexican White-lipped Frog (Leptodactylus fragilis)
Fleischmann's Glass Frog (Hyalinobatrachium fleischmanni)
Yellow-flecked Glass Frog (Sachatamia albomaculata)
Giant Toad (Rhinella horribilis)
Striped Rocketfrog (Allobates talamancae)
Strawberry Dart Frog (Oophaga pumilio)
Tink Frog (Diasporus diastema)

So my recording lifelist is now at 143 species, in 48 genera, and 15 families.

Family	Genus	Species recorded
Bufonidae
	Anaxyrus	9
	Incilius	3
	Rhinella	3

Hylidae
	Acris	3
	Agalychnis	5
	Boana	4
	Dendropsophus	3
	Hyla	8
	Pseudacris	6
	Osteopilus	1
	Scinax	4
	Smilisca	3
	Tlalocohyla	1
	Trachycephalus	1
	Triprion	1

Pelodryadidae
	Litoria	10
	Nyctimystes	1
	Ranoidea	8

Microhylidae
	Austrochaperina	2
	Elaschistocleis	1
	Hypopachus	1
	Gastrophryne	2

Myobatrachidae
	Crinia	2
	Limnodynastes	1
	Platyplectrum	1
	Uperoleia	2

Craugastoridae
	Craugastor	3
	Pristimantis	2

Eleutherodactylidae
	Diasporus	2
	Eleutherodactylus	9

Centrolenidae
	Espadarana	1
	Hyalinobatrachium	4
	Cochranella	1
	Sachatamia	2
	Teratohyla	2

Leptodactylidae
	Leptodactylus	7
	Engystomops	1
	Pleurodema	1

Ranidae
	Lithobates	9

Dendrobatidae
	Colostethus	1
	Oophaga	2
	Silverstonia	1

Hemiphractidae
	Flectonotus	1

Aromobatidae
	Allobates	1
	Mannophryne	2

Rhinophrynidae
	Rhinophrynus	1

Scaphiopodidae
	Scaphiopus	2
	Spea	2

Blue-sided Leaf Frog
Agalychnis annae

Blue-sided Leaf Frog (Agalychnis annae)
San Jose, Costa Rica

The Blue-sided Leaf Frog (Agalychnis annae) was the last new species I recorded in Costa Rica. That's because I recorded it in the grounds of the hotel we were staying at in San Jose the night before we flew home. The embarrassing thing was that the beautiful grounds of our hotel (Hotel Bougainvillia) had a couple of small ponds and one of the ponds had a sign talking about the "Golden-eyed Treefrog". I figured it was a translation problem and they really were talking about the common and widespread Red-eyed Treefrog (A. callidryas).

Blue-sided Leaf Frog range map from IUCN Redlist

On our last day in San Jose, as we walked around the grounds taking photos, I looked at the sign again and realized they were talking about a different species altogether, Agalychnis annae! As we ate dinner I looked over my Costa Rican amphibian book and was shocked to discover that not only was A. annae a different species than I had originally thought, but it was almost extinct across much of its range and there were a few remnant pockets of this species found in gardens and parks in the sprawling, polluted, overcrowded metropolis of San Jose!

So my plans for that evening were originally just to get photos of the Peralta Frogs (Lithobates taylori) that lived in these garden pools, but now I had a new and much more exciting target....if only they would call!

Turns out they did call that night even though it hadn't rained that day. We were able to find a number of these big green frogs hiding amongst the rushes and reeds surrounding the ponds. They were quite shy, preferring to cling to the stems of the reeds/rushes rather than sitting up openly on top of leaves like the other Agalychnis species I had encountered.

The call of this frog is best described as a quiet "croak" or "puck" sound. They were only calling very intermittently as heard in this recording. This frog only calls four times in the two minutes of this recording. It calls at 4 seconds, 25 seconds, 66 seconds and 104 seconds in. It takes a fair bit of patience to capture anything at all. I assume they would call more aggressively during rains?

Here's another recording made of a different individual where the calls are a bit more frequent.

Blue-sided Leaf Frog calls

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© Chris Harrison 2025

Ghost Glass Frog
Sachatamia ilex

Certainly one of the most striking frogs I was able to record in Costa Rica this year was the Ghost Glass Frog (Sachatamia ilex). These amazing frogs are almost other-worldly in appearance. Their slender green bodies, delicate limbs and amazing big white eyes with their "scribbled" iris pattern make this one of the most sought after target species to visitors in its range.

This beautiful species occurs in the foothills of the Atlantic versant of Costa Rica then south into the Darién region of Panama and into the northwestern part of Colombia. This is a frog of rocky streams in the steep rainforest valleys. They are usually found on leaves or stems at night along those rocky streams.

Interestingly, this is one of several species of frog that seemed to disappear from much of its range about 25 years ago due to chytrid fungal infections, but seems to have made a partial comeback.

Sachatamia ilex range map from IUCN Redlist Database

We found several of these Ghost Glass Frogs along a rocky stream at the Costa Rican Amphibian Research Center in the evening after some heavy daytime rains.

Like many glass frogs (Centrolenidae), the call of this species is a high pitched single note in the 7-8kHz frequency range. To my ear, the call of the Ghost Glass Frog sounds like a high pitched "tsip". When we heard them, this single "tsip" was repeated every 4-5 seconds from the leaves where they sat and called.

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© Chris Harrison 2025

Mahogany Treefrog
Tlalocohyla loquax

The Mahogany Treefrog (Tlalocohyla loquax) was kind of a white whale for me. I have been herping and looking for frogs in its range many times over the last 40 years and although I've found a lot of other frog species in that range, I could never find or hear a Mahogany Treefrog!

Mahogany Treefrog range map from IUCN Redlist

Tlalocohyla loquax is not a rare frog, ranging from the lowlands of the northern isthmus of Tehuantepec (where I have herped), over most of the Yucatan platform (where I have traveled extensively), and down into Belize (where I failed to find them) and down into northern Costa Rica (where I also failed to find them). Other herper friends would often chuckle at my inability to find this relatively common species considering how much travel I had done within their range.

Finally in August 2025, I was able to find my white whale! While searching for frogs at the Costa Rican Amphibian Research Center, Brian led us to one of his ponds in the forest and we immediately heard the percussive calls of this species. We heard two of these frogs calling back and forth at this small pond, but because they were calling from a heavily vegetated area away from the edge, we couldn't see them. We came back to that pond on multiple occasions in the days we were there and still couldn't find them. Finally on our last visit, Tim was determined to find one of these frogs to show me and eventually his eagle eyes spotted one way back through the vegetation. I was able to snap the photo posted above. My trip was complete - I had my white whale both in a photo and a recording!

To my ear, the call of this treefrog is percussive "deck" or "puck" often repeated as a double "de-deck". In this recording you can hear a couple calling on the left side. You also hear the "creek" calls of the Hourglass Treefrog (Dendropsophis ebraccatus) with the nasal trill of the Olive Snouted-Treefrog (Scinax elaeochroa) and, of course, the metallic "tinks" of Tink Frogs in the background.

In this second recording, you can hear how the notes become more complicated as the frogs start calling more often, producing a "de-de-deck" sort of call.

I found several much rarer species on our trip. But getting this frog onto the lifelist was still one of my anuran highlights of our trip!

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© Chris Harrison 2025

IUCN Redlist Database Entry for Mahogany Treefrog

Lemur Leaf Frog
Agalychnis lemur

The Lemur Leaf Frog (Agalychnis lemur) is a delicate looking leaf frog with a big head and eyes. It is a rather strange looking frog and always looks a bit emaciated to me? Their long "spidery" legs contribute to them being very good climbers.

Most of the individuals we saw were lime green with red speckles or blotches around the body, which I think contributes to its "unhealthy" look. But this is their normal coloration.

Even though this particular frog appeared healthy, this species is not. This species is regarded as Critically Endangered by the IUCN. It originally ranged from in the Caribbean foothills from northern Costa Rica through Panama. However, most of its populations were extirpated during the last 30 years, presumably by the spread of the chytrid fungus that has ravaged frog populations worldwide. It survives in a few disjunct populations through its former range. We were lucky to see and hear a large number of this species at the Costa Rica Amphibian Center near Siquirres, Costa Rica (the top yellow "blotch" in the red zone of extinction in Costa Rica on this map). Although this map suggests the species is still extant over much of its range in Panama, it has also disappeared from much of that range as well.

map from IUCN Red List Database

I'm always surprised when I listen to neotropical frog calls by how many species have short one syllable "tik" or "pik" or "tink" calls. They can sound very similar to my ear although they often differ in pitch and the frequency with which they are repeated.

The call of this species is one of those subtle, single syllable calls. To my ear it is more of a "pip" than a "tink".

In this recording, you will hear the chattering "creek-crk-crk" calls of the Hourglass Treefrog (Dendropsophus ebraccatus) and then at around 3, 6, and 11 seconds you will hear a loud "pip". That pip is our Lemur Leaf Frog. In the background you can also hear the more metallic "tinks" of the Tink Frog (Diasporus diastema). Even though the call of the Tink Frogs is also a single syllable, you can hear how it differs in pitch and "tone".

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©Chris Harrison 2025

AmphibiaWeb - Agalychnis lemur account

Australian Desert Treefrog
Litoria rubella

Well, it turns out I got another new species for my recording lifelist without ever leaving the house. In June 2025, Purser et al. published a revision of the widespread Desert Treefrog (Litoria rubella), splitting it into three species. I have never been in the range of the new western species (Litoria larisonans), but I have recorded in the range of the other two species, Litoria rubella and L. pyrina. So my previous entry for Litoria rubella actually represents L. pyrina. So I will make a new entry for the newly restricted Litoria rubella.

Technically, the "new" species for me was the one I had recorded first, the Ruddy Treefrog (Litoria pyrina). It occurs on the coast of Queensland, Australia, east of the dividing range. But the subject of this entry, the Desert Treefrog (L. rubella) occurs west of the Great Dividing range across the dry top end of Australia into the Kimberley region of WA.

I think the Desert Treefrog has quite an "ugly" frog call. It is a loud, raucous, rasping "raaahk" sound to my ear.
Here is the call of an individual Litoria rubella from outside of Kununurra, Western Australia. I was actually trying to record the "dooks" of the Ornate Burrowing Frogs (Platyplectrum ornatum), but didn't see the Desert Treefrog hiding in the grass, just to the left of my microphone. He totally "audio bombed" my recording.

And here is a noisy chorus of Desert Treefrogs (L. rubella) from near Kakadu, Northern Territory. The higher "chirp" sounds are Black-shinned Rocket Frog (Litoria tornieri).

So I got a new "old" treefrog species that I had seen many times? That's ok, they all count!

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Purser, W.A., Doughty, P., Rowley, J.L., Böhme, W., Donnellan, S.C., Anstis, M., Mitchell, N., Shea, G.M., Amey, A., Mitchell, B.A. & Catullo, R.A. (2025) Systematics of the Little Red Tree Frog, Litoria rubella (Anura: Pelodryadidae), with the description of two new species from eastern Australia and arid Western Australia. Zootaxa, 5594 (2), 269–315. https://doi.org/10.11646/zootaxa.5594.2.3

Belize - fail...

Just got back from a trip to Belize where I had hoped to add a couple of species to my lifelist since it was the beginning of the wet season. The purpose of the trip was to visit a friend who lived there, not frog recording, but I always have my gear with me!

Unfortunately, we were staying in an area of mangrove lowland swamps and the mosquitos were so oppressive, we didn't get out much at night to listen to frogs. I never even heard any new species. 😭

We did see and hear

Vermiculated Treefrog (Trachycephalus vermiculatus)
Yucatecan Casque-headed Treefrog (Triprion petasatus)
Mexican Treefrog (Smilisca baudinii)
Stauffer's Treefrog (Scinax staufferi)
Giant Toad (Rhinella horribilis)
Southern Gulf Coast Toad (Incilius nebulifer)

But all of those species were ones I had seen/heard/recorded before. I needed a better recording of the Trachycephalus, but the time I tried to get them, they shut up and the mosquitos drove me back to the porch.

The locals said this was the worst time of year for mosquitos. The first few rains of the season cause a massive mosquito hatch and either two weeks earlier and a few weeks later they are better.

We did travel inland to some rainforest and marsh areas and the mosquitos weren't nearly as bad, but we didn't hear any frogs there.

So here's my few recordings as proof I've been to Belize!

Stauffer's Treefrog (Scinax staufferi)

Yucatecan Casque-headed Treefrog (Triprion petasatus), Southern Gulf Coast Toad (Incilius nebulifer), and Mexican Treefrog (Smilisca baudinii).

Veined Treefrog
Trachycephalus vermiculatus

The Veined Treefrog (Trachycephalus vermiculatus) is a large species of neotropical treefrog found from central Mexico down to the central regions of South America. They are large frogs often with very beautiful patterns. Interestingly, like all members of the genus Trachycephalus, this species of frog has green bones.

If you are looking in a field guide for Mexico or Central America, you might see this same species under the scientific name Phrynohyas venulosus or Trachycephalus venulosus or Trachycephalus typhonius. Those had been their scientific names throughout their taxonomic history until a recent revision of the typhonius group showed that the name this northern population was its own species and the name vermiculatus pre-dated the name venulosus. Therefore under the rules of taxonomic nomenclature Trachycephalus vermiculatus had precedence.

However, this group of frogs is still a mess. Some authorities still say all the Mexican, Central American and Guinanan shield populations belong in T. typhonius. And regardless of the correct name, this "species" is probably a group of species all lumped together. The "real" T. vermiculatus (or typhonius?) is probably restricted to the Guianan shield in South America, so these Mexican species are probably something different? And then there is the issue of there being an isolated population on the West Coast of Mexico that may not be the same species as the Yucatecan form I am discussing. . Confused? How about we just call them Veined Treefrogs?

Here's a range map from iNaturalist showing the "whole species" range.

The old specific epithet "venulosus" is a reference to the numerous glands on the frog's back from which it secretes a sticky white toxin when disturbed. Lots of frog species secrete similar toxins, but the Veined Treefrog has taken this skill to a whole new level. Just handling one for a few seconds can leave your hands gummed up for hours. It must take a very persistent predator to swallow one of these sticky frogs. This ability has given some of the South American relatives of this frog the name "Milk Frog". Here's what my hands looked like after holding one of these frogs for just a few seconds!

I have seen this species of frog many times in the past, but only once have I had my recording gear with me while they were calling. And I didn't get a very good recording so I decided not to upload that one to iNaturalist until I got a better one. That was 8 years ago. I decided that I might as well upload this species now in the hope that this would give me a chance to get better recordings this year when I travel to Belize. As a lifelong birder, I know the old adage that the first one is the hardest one to get. Once you see the first one of any species, you will start seeing them everywhere. 😏

So this recording was made in June of 2017 in on the northern boundaries of the Calakmul Biosphere Reserve, Campeche, Yucatan. It had rained very hard in this area earlier in the day and lots of frog species were calling. I pointed my microphone out into the marshes and recorded many species, including a distant chorus of Veined Treefrogs. I have brought out the Veined Treefrogs in this recording and reduced the gain for all the other species.

The call of this species is a deep "roon". It is remniscent of the call of the American Bullfrog and a large chorus of these Veined Treefrogs does sound a bit like that species. The two species do not overlap in range though.

The other species heard in this recording include Stauffer's Treefrog, Mexican Treefrog and the Sheep Frog.

Veined Treefrogs, et al. from Campeche, Mexico

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Eastern vs. Northern Sedge Frogs
Litoria fallax vs. Litoria bicolor

Australia has several species of small grassland frogs called Sedge Frogs. They are sometimes called Dwarf Treefrogs but I think the name Sedge Frog is more descriptive of their grassy habitats. All the Sedge Frog species are small green frogs with a brownish border running from their nose through their eye towards the rear of their body. They can be green or tan, with or without a brown stripe down the back.

Northern Sedge Frog (L. bicolor) from Fogg Dam in the Northern Territory
In this case, this frog can be identified by range.

Sedge Frog (Litoria cf. bicolor) from NE Queensland.
Although this best matches descriptions of L. bicolor, it is difficult to be certain.

Eastern Sedge Frog (Litoria fallax) from NE Queensland.
In this case, the species identity could be confirmed by call.

The Eastern Sedge Frog (Litoria fallax) is found along the east coast of Australia from the tropics near Cooktown south to Victoria. The Northern Sedge Frog (L. bicolor) is found from tropical NE Queensland across the northern part of the country to Kimberley Region of Western Australia. On the map below, the Eastern Sedge Frog is represented by the golden color, the Northern Sedge Frog by the teal color and you can see their area of overlap in NE Queensland by the lighter blue region. This is where I ran into trouble with the two species.


Range maps for Litoria bicolor (teal) and Litoria fallax (gold) showing region of overlap. Shape files downloaded from the IUCN Red Book and overlayed onto Google Earth

While trying to identify frogs in that overlap area, I found myself struggling to distinguish between these two species. They can be green or tan, with or without a brown stripe down the back. Field guides say that they can be distinguised sometimes by the fact that L. bicolor more often has a dark stripe down its back, but both species can show that character. Supposedly the dark stripe on the Northern Sedge Frog (L. bicolor) goes further back onto the "tail", whereas it tends to fade on the Eastern Sedge Frog (L. fallax).

Now obviously if you've read any of the other "similar species" comparisons I have on my blog, you would expect me to say, "but fortunately, their calls are very different and easy to distinguish". But in this case that isn't true. Their calls are different and can be distinguished but the difference is more subtle and can be hard to discern when listening to a chorus.

Both species have a call that consists of one or two "chuck" sounds and an upward slurred raspy trill. The trill sounds like a fingernail over a very delicate comb.

Here's the Eastern Sedge Frog's (L. fallax) call -

Eastern Sedge Frog calls

And here's the call of the Northern Sedge Frog (L. bicolor) -

Northern Sedge Frog calls

Hear the difference? It is pretty subtle.

The difference lies in the order of the "chucks" and "trills". Although both species make one or two "chucks" and a trill, the order is different. The Eastern (fallax) makes a trill followed by one or two "chucks". The Northern (bicolor) does the opposite, a trill followed a "chuck" or two.

So the Eastern Sedge Frog calls trill-chuck-chuck (or trill-chuck).

The Northern Sedge Frog calls chuck-chuck-trill (or chuck-trill).

The tricky part is if you are listening to a big chorus, it can be hard to figure out who is starting where?!

Listen to this group and see if you can tell if it is chuck-chuck-trill or trill-chuck-chuck?

How about this one?

The first recording was Northern, the second recording was Eastern. Simple, right? 😆

Here's a visual showing the two species on a spectrogram. You can see the different arrangement of chucks and trills. Ignore the differences in frequency (pitch). That is temperature dependent, not species dependent. They were recorded at different times (years!) in different places with different recorders and microphones.

I had the hardest time telling these things apart in NE Queensland until I heard what could only be Northerns in the Northern Territory. Once I heard their calls, I understood and could hear the difference.

Now I want to go back to NE Queensland to try and hear them again. Who am I kidding? Any trip to NE Queensland for any reason would be fine. 😉

Yellow-flecked Glassfrog
Sachatamia albomaculata

Yellow-flecked Glassfrogs in amplexus
Costa Rican Amphibian Research Center

The Yellow-flecked Grassfrog (Sachatamia albomaculata) is a delicate glassfrog species found in lowland wet forests of Central America. From maps I have seen, it has an rather discontinuous range Northern Honduras south through Costa Rica and Panama into western Colombia, but then also shows up again in Ecuador. This may represent more of a lack of data than the true range of the species.

Map derived from range map on iNaturalist.org

This was another bonus frog species I recorded accidentally. I had seen it before on an earlier trip to Panama, but not heard it. In January 2025, I was trying to record some Red-webbed Treefrogs and Harlequin Treefrogs around the pond on our hotel grounds. When I posted those recordings to iNaturalist, neotropical frog expert and iNat user ibanezr confirmed my IDs, but added that he could hear Sachatamia albomaculata in the recording as well.

This led me down a rabbit hole to try to find what this species sounds like and then isolate it from any of my recordings.

The call of this species is a high pitched peep or tick with a dominant frequency ~6600 Hz. Because of its high pitch I probably dismissed it as an insect in my original recordings. (This recording is filtered and edited to remove some of the other distracting species of frogs heard calling.)

Yellow-flecked Glassfrog calls from Panama

P.S. - In August 2025, I was able to see a number of this species calling and in amplexus at the Costa Rican Amphibian Research Center thanks to Brian Kubicki!

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