Exploring Costa Rica's Undiscovered Wetland

Pinnated Bittern - Medio Queso

Mention Costa Rica as a birding destination and you'll quickly start hearing about cloud forests like Monteverde and the Dota Valley or lowland rainforests like La Selva and the Osa Peninsula. But it's not all about forest birding - Costa Rica boasts some fabulous wetlands packed with an enticing range of birds and other wildlife. The most famous include Palo Verde National Park, sited in the otherwise dry forests of the north east, and Caño Negro up in the north, which drains over the border into Lake Nicaragua.

But there's another wetland near the Nicaraguan border that is much less well known, and far more accessible than Caño Negro. This is Medio Queso, which bafflingly translates as 'half cheese'.  Only a short drive east of Los Chiles, the last town before the Nicaraguan border, the wetland is reached by a road that starts near the local airport and, at the time of our visit, ended next to a new bridge (still being built in late 2024) across the Rio Medio Queso. A small dock beside the road is the starting point for a boat ride that explores these productive marshes.  

Medio Queso - relaxed wetland birding

Boat trips have provided some of my tropical birding highlights, and our visit to the wetlands of Medio Queso was no exception. The weather was hot, still and sunny as we cruised under the bridge and headed north along the main channel. The expansive view towards the hills of Nicaragua (above) was a refreshing contrast to the crowded forest trails that we'd experienced over the previous few days. 

Although excellent for birds, the Medio Queso wetlands are not protected – apart, oddly, for the small part over the border in Nicaragua, although you wonder what that means in practice. Our guide, Pat O'Donnell, had done his best to put the place on the Costa Rica birding map, and the presence of boat, boatman and local guide were encouraging signs. (There's more on Medio Queso in Pat's blog - link here).

Northern Jacana - Medio Queso

Water levels were high, and Pat was concerned that it might be harder to locate the key species. As it turned out, we did pretty well. This Northern Jacana (above) gave wonderfully close views. I love jacanas. For me they are a definitive bird of tropical wetlands, effortlessly balancing on lily pads in their hunt for a watery meal. Northern Jacanas look especially smart, with their yellow frontal shield and cool chestnut and black two-tone livery.  Northern Jacana females hold a territory containing up to four males (the technical term is polyandrous) and may be juggling several pair bonds at the same time. Males do most of the parental jobs like incubating eggs and brooding chicks, although females will step in to help at times. Very good of them, I’m sure.

Pinnated Bittern posing at Medio Queso

The jacana was only the start. The boat's passage startled a Pinnated Bittern (above and at the top of this blog post) which was stalking through the shallows. It flew off down the channel in front of us and landed a couple of times before being displaced again as we approached. In the end it gave up and flew off to one side. Pinnated Bitterns share the tendency of their Eurasian cousins to sit silently in reed beds, so getting a clear sight of one like this was very satisfying. The species has an oddly disjointed distribution, being found in various corners of the Neotropics including southern Mexico; a strip across northern South America; and an area including northern Argentina and Paraguay. It is absent from the Amazon basin.

Least Bittern - Medio Queso

A bit of a commotion on the boat announced the sighting of a Least Bittern (above). The guidebooks will tell you that this is an uncommon species in Costa Rica that is difficult to see because of its habit of skulking in dense vegetation. Well, this one was positively showy. In the Birdlife/HBW Checklist (which is the one I follow) Least Bittern is in the same genus (Ixobrychus) as Europe's Little Bittern, which it kind of resembles, and Australia's Black Bittern, which it doesn't. The bird's diminutive size isn't obvious from the above photo, but I can tell you that this is a seriously small heron. 

Neotropical Cormorant - Medio Queso

Rather more common, this Neotropical Cormorant (above) was nicely perched on a cecropia branch. (All of my other sources say ‘Neotropic’, but I’m sticking to the Checklist spelling.) The default cormorant for Central and South America, this species ranges from Texas down to Patagonia. 

At this point there was a burst of excitement as a low shape chugged over the waterway some distance ahead of us - my first Sungrebe. Not a great sighting, and no decent photograph, which is not ideal for a 'lifer' bird, but its characteristically long profile lying low in the water was distinctive enough. Sungrebes are bird oddities, sitting in the same small family as the Finfoots (Finfeet?!). They have a wide distribution across the Neotropics, so I'm sure that a better encounter will come along in the future. But life would dull if every bird sat up nicely for a photograph, wouldn't it? (Wouldn't it??)

More obliging was this Green Heron (above) eyeing up some movement in its riverside tree. It took me a while to be certain of the identification, as it differs from most of the other Green Herons that I’ve seen. This is because it's a juvenile, which is lighter and more streaky than the adult. The dark cap is a bit of a give-away, as is the white stripe below the eye. 

Anhinga - Medio Queso

Nearby, a snake-necked Anhinga (above) sat on the top of another riverside tree, surveying the marshy landscape. Also seen here, but not photographed were Slaty Spinetail, Scissor-tailed Flycatcher, Green-breasted Mango and a Purple Gallinule (below), which was having a bit of a skulk behind some watery vegetation. Think of a large, blue Moorhen and you've got the general idea. 

A Pied-billed Grebe sat at a distance with two young; also here were Snowy and Great White Egrets, Mangrove Swallow, Variable Seedeater and a neat little Common Tody-Flycatcher (below - this photo is actually from Pocosol a couple of days previously). 

Common Tody Flycatcher - Pocosol

Two Little Blue Herons flew over, followed by a flock of Red-winged Blackbirds. A White-throated Crake (below) chugged speedily across the river, white throat not visible. These are Costa Rica's most common crakes, being found in most wetland areas.

White-throated Crake moving at speed - Medio Queso

Yellow-breasted Crake - Medio Queso

Getting good views of birds like crakes is the mark of a successful wetland visit, and here at Medio Queso we were favoured by a second species - the Yellow-breasted Crake (above). This started to stalk away at speed over the lily pads when it caught sight of us, so the field marks are not all easily seen. But you can just make out the black stripe through the eye.

Spectacled Caiman - Medio Queso

It wasn't only birds. This Spectacled Caiman (above) has the sort of smug expression that says ‘I am in a good place for a caiman to be’. Limitless prey and plenty of cover. Although a common species in the Neotropics, it's always good to see one. The presence of the small crocodilians always seems to make a wetland seem all the wilder, even if they are considerably less dangerous than some of their larger cousins.

We had seen Groove-billed Anis on the previous day’s drive up to Los Chiles, but it was good to get a better look at one sitting near the watercourse (below). The grooves in the bill are just about visible here.  Although in the cuckoo family, Anis are communal breeders rather than brood parasites. Females nest together and share duties of feeding and incubation.

Groove-billed Ani - Medio Queso

Now the boatman turned around, and we puttered back under the bridge where we’d begun, continuing on to explore the channel to the south. Several stands of mature trees flanked this section of river, and a number of smaller birds were added to the list: Thick-billed Seed-finch, Canebreak Wren, Orchard Oriole, Barred Antshrike and Rose-breasted Grosbeak. And I realise that I've forgotten to mention this flying Roseate Spoonbill (below) seen earlier in the day; it was quite distant, so my photo doesn't do it justice. They are (literally) brilliant and startling additions to the wetlands of the Neotropics.

Roseate Spoonbill - Medio Queso

The morning had warmed up and raptors were starting to appear. A hawk (below) circled above us, before diving down into the reeds. There was some debate about what it was: Pat suggested White-tailed Hawk, which was confirmed when it flew up again. The single dark band at the tail end is diagnostic; the mopre common Short-tailed Hawk, which has a similar head pattern, has lighter bars on the tail. Also, the wing shape – this is broad and pointed, with a relatively straight trailing edge. Short-tailed Hawk has a more rounded trailing edge. White-tailed Hawk has two colour phases: this was the more common light morph. But it was surprising to see it here because Medio Queso is out of the range shown in the field guide. Very much a species of open lands rather than the forest.

White-tailed Hawk - Medio Queso

The hawk was a suitable way to sign off a magical morning of relaxed wetland birding. The next day we would be back on the rainforest trails - but that's another story.

References

Garrigues, R. and Dean, R. (2014) Birds of Costa Rica (2nd ed). London: Helm

Link to purchase Pat O'Donnell's guidebook How to See, Find, and Identify Birds in Costa Rica