In the realm of birding, we love surprises! At least, we love the good ones; unexpected happiness in the form of a Swallow-tailed Kite floating into view over the shaded streets of Buffalo or other places north of their usual range. Vagrant birds, skulking birds on an open perch, a Great Black-backed Gull that does not go naturally psycho on a rare stint or naive first year Ross’s Gull; we love avian surprises like these and more.
In Costa Rica, we had one such an avian surprise this past June. Well, we had more than one but the surprise bird sighting that stands out was a Rufous-vented Ground-Cuckoo at the Horizontes Station in Guanacaste. To see why this was a big surprise, check out where the station is located on this map, and where the nearest Rufous-vented Ground-Cuckoo sightings are in eBird.
To summarize, Horizontes is in tropical dry forest while all other sightings of this elusive bird come from expected humid forested habitats. The bird ain’t where it’s supposed to be! And if it weren’t for the trail camera that clearly captured images of the bird, we would have never known about it.
In Costa Rica and elsewhere, ground-cuckoos showing up on trail cams is nothing new. It’s how we found that the species occurs in Cangreja National Park (which was well outside of their known range), and how they have been detected in other parts of their range. It’s also why it would be nice to have some trail cams in different parts of Carara. The bird has been seen there too but only on two occasions that I know of. However, I suspect small numbers occur in the more humid and inaccessible parts of the park.
However, note that Carara is humid rainforest, sort of where one might expect a Neomorphus while Horizontes is tropical dry forest. What gives? How the heck did it get there!?! There’s a couple of possibilities. One is that this species has always lived in that area and came from the taller, more humid dry forests of Santa Rosa National Park. Since there have been zero g-cuckoo sightings in Santa Rosa despite decades of research having been carried out there, I don’t think that’s the correct explanation.
The second option is that the bird (or birds) have wandered from known haunts on Rincon de la Vieja all the way into the lowland forest habitats of Horizontes. Even though this seems unlikely at first, there’s no other good explanation and, when we look into a few factors, we can see how it could happen. Check it out:
Distance not incredibly far– Although Horizontes is not adjacent to Rincon de la Vieja, it’s not all far, especially for a ground-cuckoo. In a straight line, Horizontes is 15 to 20 kilometers to the nearest ground-cuckoo habitat on Rincon de la Vieja.
These birds don’t like to fly but they cover a heck of a lot of ground on foot! They have big territories and perhaps disperse over large areas.
Connected habitat– Looking at a map, there’s not a lot of forest connections between Horizontes and the slopes of Rincon. However, look closer and you can see some riparian zones snaking down to meet Horizontes or other forests connected to that area. We can only assume that the bird used these green trails to reach its destination (even crossing the Pan-American highway in the process).
Tropical Dry Forest?– This habitat is definitely not prime living space for a Rufous-vented Ground-Cuckoo. In Costa Rica and most of its range, they seem to only live in dense, primary rainforest that can supply the high variety of arthropods and other small creatures these apex understory predators feed on.
With that in mind, I have to wonder how long that bird is going to survive at Horizontes. Right now, with all that rain going on, it’s probably got plenty to eat but when the water stops and plants and bugs go into hibernation, it’ll be a challenge to survive.
However, it is worth mentioning that this species occurs in somewhat dry, intermontane valleys around Apolo Bolivia and may even be more common there than other sites in its range. Perhaps it’s a bit more adaptable than we realize? The bird surely still needs plenty of productive habitat to maintain a population but maybe there’s more of those smart and sneaky rainforest roadrunners than we think.
Coming back to option one– Could the bird have encountered Horizontes from the Santa Rosa area anyways? It could have and forest habitats are bigger and more connected from that direction but, if so, why wouldn’t it just stay where there’s more habitat? Like, why go all the way to Horizontes when you’ve already got more intact forested areas to play with? Could there actually be a small population in some part of Santa Rosa that we aren’t aware of?
Although that still seems unlikely, with this ultra sneaky bird, it seems like a lot more is possible than expected!
With that in mind, where else might ground-cuckoos occur in Costa Rica? At least one person hints at seeing one in the Osa and that would seem to make sense but what doesn’t jive is hundreds of other birders never seeing one there ever. Given that it occurs in Cangreja and Carara, might it also occur in some other parts of the Pacific slope?
Some places to look for it (which are also mostly underbirded) could be the Cambronero area and forests south of San Ramon, forests above Miramar, forests west of Monteverde, and maybe even habitats uphill from the Quepos area.
If you do some exploration birding in those areas, keep that in mind! Whether birding there or in dense rainforest (especially the foothills), if you think you hear some quiet clacks or snaps, or hear cowish/doveish vocalization, take a closer look. The understory might be hiding a mega avian prize.
To learn more about birding sites mentioned in this post while supporting this blog, get my 900 plus page birding site guide to Costa Rica. I try to keep it up to date and if I edit it soon, will also send you that recently edited version. I hope to see you in birdy Costa Rica!
