How many birds are on the Costa Rica list? Although some sources mention somewhere around 870 or so species, the official list of birds for Costa Rica has 923 species. Why the discrepancy? I’m not entirely sure but part of the difference is surely related to bird species having been steadily confirmed and added to the country list.
While most are vagrants, given changes in habitat, distribution, and populations of various species, it’s not out of the question that there could be more of certain vagrants, and that some “new” species could establish breeding populations.
The official list has grown but believe it or not, there’s room for more! In fact, much more than I had expected. After having looked into the most likely additions for Costa Rica, quite a few more species came to mind than I had imagined (and I never even thought about Orinoco Goose but that’s another story). This post is the first in a series discussing birds that may eventually find themselves on the list and is in conjunction with a separate post written by fellow local birder, Diego Ramirez (aka “Mr. Birder”). He wrote a good post about this theme in Spanish, check out, Las Potenciales Nuevas Especies de Aves para Costa Rica.
Although the occurrence of any of these species would be an occasion of extreme rarity, for various reasons discussed below, all of them are possible. While none of these can be really expected when birding Costa Rica, I feel like it’s better to know about what might occur, to have that information available, than potentially overlooking a country first because a Long-toed Stint was assumed to just be a funny looking Least Sandpiper, or that the Black-headed Gull was a weird Bonaparte’s with a red bill.
This is also why the latest free update for the Costa Rica Birds field guide app includes 68 species that aren’t on the list but could occur (photos used in this post are screenshots from this latest update to the app). Despite such a high number of potential species, much to my chagrin, I realized that I had left out at least 3additional species. Expect those on the next update! Without further ado, the following are some birds to keep an eye out for when birding in Guanacaste (expect shorebirds in a future post!):
Gadwall
Yep, the good old Gadwall. A familiar, svelte species for many birders of North America and the Palearctic, it has yet to fly south to Costa Rica. Given its large population and strong possibility of migrating with other ducks, I believe this species is one of the strongest contenders for being the next addition to the list. The marshes of Palo Verde and nearby sites, the Sandillal Reservoir, and the catfish ponds of Sardinal would all be good places to check.
Spot-tailed Nightjar
What? Yes and Eduardo Amengual and Robert Dean one may have actually seen one in 2003. The Spot-tailed Nightjar is a small nightjar of savannas and other open habitats that has migratory populations in southern Mexico and northern Central America. Where do they go for the winter? No one really knows and it would be very easy for s small, nocturnal bird to go unnoticed during migration, especially if it is silent. Heck, if a few of these inconspicuous nightbirds wintered in Guanacaste, they could also easily go unnoticed.
Guanacaste Hummingbird
No, I’m not making this up, this is one of the names given to a mystery hummingbird known from one old specimen and referred to as, “Amazilia alfaroensis“. Searches have been carried out yet have failed to refind it. Nevertheless, maybe it’s still out there? If you are birding around the Miravalles Volcano or other sites in northern Guanacaste, keep an eye out for any odd-looking Blue-vented Hummingbirds, especially ones that have blue on the crown. Take pictures, if you find one, you will have refound a critically endangered “lost species”.
Ladder-backed Woodpecker
This small woodpecker of open habitats could certainly occur at some point in the Upala area. There are sightings of this species from sites near there, just across the border in Nicaragua. If you think you ehar a Downy Woodpecker in that area, it’s very likely a Ladder-backed Woodpecker.
Pacific Parakeet
Given the propensity for parakeets to wander, group up with other parakeets, and possible sightings in Nicaragua close to the northwestern border with Costa Rica, this species should be looked for. If I get the chance to bird up that way, I would look for flocks of Crimson-fronted Parakeets and carefully check them for birds with green fronts. Flowering trees might be a good food source, and in the southern esge of its range, the Pacific Parakeet might be partial to mangroves.
Cassin’s Kingbird
This one is a long shot but since one was found in Panama, it could certainly occur in Cost Rica as a very rare migrant vagrant. In other parts of its range, this typical kingbird uses a variety of open habitats, often in grasslands with tall trees. With that in mind, a vagrant Cassin’s Kingbird could show up anywhere in Guanacaste and be easily overlooked as a Tropical Kingbird. I would not be at all surprised if a few have made it to Costa Rica now and then.
Altamira Oriole
This beautiful bird is just waiting to be found. It occurs in Nicaragua fairly close to the border with Costa Rica and lives in a variety of scrubby and dry forest habitats. It could also be very easily overlooked as a Streak-backed or Spot-breasted Oriole. Watch for it at flowering trees near the border, look for orioles that have a small patch of gray on the base of a stout bill and no spots on the breast.
Other possible additions could occur in Guanacaste such as Blue-gray Gnatcatcher, Cassin’s Vireo, and Virginia’s Warbler. It’s a reminder to take a close look and listen at every bird, you really never know what you might find.