seabirding in Costa Rica

Seawatching at Puntarenas- September 20, 2025

Costa Rica is flanked by two oceans; drive quick enough, get lucky with traffic and weather and you can visit both in a day. Not stopping to look at any of the hundreds of bird species in between would be an incredible birding shame but, if you were so marine inclined, you could do it.

Or, you could do better at managing your birding time and go seawatching! Sure, in Costa Rica, you could certainly seawatch on both coasts. You might not see much but there’s always a certain degree of therapeutic benefits associated with oggling the waves. The funny thing about seawatching is that although you can technically watch for birds on any coast, not all coasts have the birds, at least not near shore, or in enough numbers to breach birding appeal.

Take Costa Rica for example, we’ve got many wonderful spots to watch those tropical waves but few of them really bring the birds. Yeah, no matter where you look, you’ll probably see something with feathers but, more variety calls for strategic spots at strategic times (just like any seawatching hotspot).

One of the best spots for seawatching in Costa Rica is an old port city situated on a narrow peninsula that points into the Gulf of Nicoya, just about where the inner and outer parts of the gulf meet. It’s a sort of a tropical headland at a joining of waters and an estuary replete with sand bars. Now if those sand bars were closer Puntarenas would be a major shorebird watching hotspot. Alas, the birds are a bit too far to properly observe them but, the port is still good for scanning the water, for getting in some good old fashioned seawatching.

Knowing that Least Terns should still be moving through and, dearly wanting to see some of those dainty birds as they make their annual journey south, yesterday, we paid a morning visit to the Puntarenas lighthouse. The drive to the coast was slowed a bit by truck traffic but we still got there by 7 a.m., still early enough to catch some of the morning seabird action.

These are some highlights and thoughts from this birding sojourn.

Take a closer look

Upon arrival, I looked at the water and saw nary a Royal Tern. Those birds are a given, not seeing them did not bode well. “At least there was the ocean” I thought, “maybe something will fly by or I’ll see a fish”.

After exiting the car and briefly conversing with the car watcher guy (aka “watcheemon”) to yes, assure that I as aware he was watching over my vehicle, despite my low bar hopes, I set up the scope and started scanning with binos. Lo and behold, the birds were there, they were just mostly horizon birds, mostly things flying way out there over distant water.

But there were a lot, they looked like innumerable gnats on the horizon.

The ferry would have been pretty darn good

Upon seeing that lots of birds were out there, I realized it would have been a good day to take the ferry. Why hadn’t I thought of that? That’s right, it was because we would have had to leave the house by 3 and weren’t too keen on going back and forth across the gulf. But, if only we had!

The birds were out there and some. It looked promising and was more or less the same time of year when I had my best birding ferry ride some years ago.

Least Terns

It didn’t take long before a few Least Terns flew by; tiny terns with quick wingbeats, all in dapper white winter plumage brushed with bits of black. Throughout my 90 minutes of seawatching, small groups flew past and foraged by the distant sand bar. Even at a distance, it was easy to pick out their distinctive, repetitive quick dive foraging.

I put down 50 for the list but there was probably more. It was fun to compare them with the most abundant bird on the scene, another small tern often found in the Gulf of Nicoya. It’s a bird that nests in northern marshes, one that brings back visions of smart-looking birds hovering and swooping over the Tonawanda wetlands.

Clouds of Black Terns

A typical feeding flock of Black Terns in the gulf.

Like I was saying, the Black Tern was the big bird on the scene, the one that ruled my seawatching day. Small numbers constantly flew past, most fairly far off shore. The largest numbers were way out there, clouds of them. In one such cloud, at a wavery 60 X magnification, as much as I tried to pick out another species, all I could see was a massive Brown Pelican plowing through the Black Tern ranks to feast on the same unseen sardine banquet.

A few other groups foraged a bit closer and in better light and those were the ones to focus on. Those were the flocks that would have been exciting to watch from the ferry deck. Although such flocks can be solely composed of Black Terns, they are also the situations that attract other, less common species, including the ones mentioned below.

I should also mention putting down 1,000 Black Terns on my eBird list. That was a pretty conservative estimate, there were probably a lot more.

A few distant pelagic birds

A Brown Noddy from another day shares a piece of driftwood with a Black Tern.

Fortunately, the scanning paid off, the seawatching revealed some of the seabird bounty from the Gulf of Nicoya. Try as I did to pick up a storm-petrel or two, no luck there. However, staring at the Black Terns and carefully panning the waves did turn up a couple Bridled Terns (!). The distant looks ruled out divining their age but that’s alright, I’m fine with ageless Bridled Terns, smiling with picking out larger, longer winged, gray backed terns that sliced through the tern flocks.

I was also alright with a Brown Noddy doing the same; a larger, dark brown bird foraging with the smaller migrants from the north. The third pelagic bird species was hardly a glimpse but I couldn’t unsee it, couldn’t deny noticing the fluttering flight and banking of another regular in these estuarine waters; a Galapagos Shearwater.

It was less than a second but it was enough to know I saw it. I bet more were out there and who knows what else? I hadn’t picked up any Sabine’s or phalaropes or jaegers but those are moving through too, might have been some visible from the ferry.

No ferry for me but the seawatching was still good, still therapeutic and highlighted with a jumping stingray and a pair of surfacing Bottlenose Dolphins. It was good stuff, I am grateful.

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The El Niño Birds Have Arrived in Costa Rica

It’s official, 2023 is an El Niño year. In other words, the waters of the central Pacific Ocean are warmer than usual and will affect weather in various places. Some regions will be wetter, others will be hot and begging for rain. We don’t know yet how long it will last but the peak might not happen until December.

In birding terms, this weather cycle means that some birds may take advantage of the rains but others will suffer. Sadly, seabirds have a rough time, especially species adapted to cold water, especially the ones that live in the Humboldt Current. Those cold waters off the coast of Peru and Chile are a true marine bio bonanza. I can easily picture the first time I witnessed their avian abundance.

Some years ago, I was traveling by bus in Peru, somewhere along the coast north of Lima, maybe near Lomas de Lachay, an important reserve protecting arid vegetation sustained by coastal fog. The land was incredibly dry and barren but offshore, there were flocks and flocks of birds. Hundreds of Belcher’s and Gray Gulls, wintering Franklin’s Gulls, Inca Terns, Peruvian Boobies, pelicans, and cormorants.

The contrast between life in the desert and in the cold gray waves was astounding. On a trip to the Paracas Peninsula, I got a closer look at the incredible amounts of life supported by the cold currents. As the boat made its way to view cormorant and penguin colonies, I noticed dark areas in the water, long, dark lines below the surface. Looking closer, I could see that they were fish!

There were literally millions of anchovies or some other baitfish, massive numbers of small lead-colored fish that formed living rivers beneath the waves.

These were the building blocks of the huge cormorant colonies offshore, the life support system for penguins, pelicans, larger fish, and, I suppose, most everything out there.

A scene from the Paracas Peninsula in Peru.

But those small fish need cold water and birds can only dive so deep. If the ocean warms up, I’m guessing the anchovies go deeper, head to the cool depths because it’s do that or die. Since this is such a big change to their regular ways, I’m supposing that the fish don’t fare well. For the birds, it’s a disaster.

The boobies and other birds that depend on those and other cold water fish simply don’t have enough food, To cope, they do like the gnus, so like any mobile animal that can’t find enough to eat. They split, and keep on moving until they find enough food to survive.

That basic need brings them far north of their usual range, this year, some as far as 1,586 miles (2 552 kms) to Costa Rica. That’s the distance from Lima to San Jose on a plane. For a bird, the trip is probably similar in length but instead of six boring hours of sudoku in a metal tube, they flap their way over countless waves, always pushing north, looking for cooler waters, joining the other birds of the oceans in their search for accessible baitfish.

Given the current El Nino situation and sightings of Peruvian Boobies from Panama, I figured the odds were good for this and other species reaching Costa Rica. A few days ago, that forecast came to pass when four Peruvian Boobies and a juvenile Inca Tern were found on rocks off of the Osa Peninsula. The arrival of Humboldt-related birds has also been happening in the form of Sooty Shearwaters.

Several of the dark shearwaters have been seen on recent pelagic trips, much more than usual. The sightings are notable but we’ve been hoping for rarer birds to appear on those trips. No dice, though, at least not yet.

With the recent Peruvian Booby sightings in mind, I figured today would be a good day to visit Puntarenas. The port city is the most accessible and reliable hotspot for vagrant seabirds in Costa Rica, all you gotta do it get there and start scanning from the lighthouse, right from the tip. Whether because of the mixing of inner and outer gulf waters or because it sticks straight into the ocean, or a blend of those and other factors, Puntarenas turns up the birds.

You might have to wait a while, you will be offered trips to watch dolphins by a guy a bike, and someone will probably try to sell you something but, if you are diligent, you will also see birds. Watch carefully too because you can see some seriously good birds!

Puntarenas is a place for the unexpected flying in with the usual. It’s all good and the longer you stay, the more you’ll see. This morning, we started our birding in Puntarenas at 7 a.m., scanning calm ocean waters. At first, it seemed dead. Where were the pelicans? What about all of the frigatebirds?! The seeming absence of birds was rather alarming but what could we do? The only thing to do was wait and keep watching and sure enough, the birds eventually showed.

One of the first ones we saw was a surprise young Elegant Tern. I expect the slender-billed birds in winter, not so much in summer. It flew past, we never saw it again and began to see more Royal Terns as other regulars flapped into view; small flocks of White Ibis and egrets flying across the gulf, Mangrove Swallows and Gray-breasted Martins zipping over the waves, and fish action.

Scanning the water, we could see dark patches here and there, baitfish being driven to the surface, some flying clear out of the water in their quest for immediate survival. Sometimes, an enticing larger fin would break the surface, a few Devil Rays jumped, and we had great views of the Bottlenose Dolphins that live in the Gulf of Nicoya.

With the baitfish happening, I still wondered, “Where were the birds?”. Scanning eventually revealed some terns and other birds flying inside the gulf and larger numbers as specks on the horizon. Some birds from the inner gulf flew towards us. A few Sulids….not dark enough to be a Brown Booby…dusky head, white tail….Blue-footed Booby!

A Blue-footed Booby from a few years ago.

We had at least four and that was sweet. I hadn’t seen any for a few years. Scan some more and wait…what’s that? Small black and white football of a bird fluttering and gliding low over the water. Yes! Galapagos Shearwater from shore!

It made its way to the inner gulf and that’s when I noticed a black and white bird floating way out there. I said, “Now that’s an interesting bird, I hope that comes closer!” From a distance, it looked black and white, a pattern sort of like a female frigatebird. The only thing that came to mind was one of those lost Peruvian Boobies but to clinch the identification of such a rarity for Costa Rica, closer looks were needed.

Thankfully, that suspicious black and white bird tired of sitting way out there, eventually took to the air, and made its way towards us. Closer it came and I wondered if it would keep coming and give us a super close, detailed flyby. No dice there but it did fly near enough to clearly see that it had a bright white head, dark back, and looked like some dark marking on the face or throat. No doubt about it, even trying to turn it into something else, I had to admit- Peruvian Booby!

I figured this would be a good year to find one at some point but it’s really nice when a hunch pays off. We watched this Costa Rica El Nino mega make shallow dives into the water and float way out there for at least half an hour but had to leave it to its floating ways so we could scan for other birds.

Heck, there might be a tropicbird nearby, there could be an Inca Tern flying way offshore or a storm-petrel or some other major bird. Further scanning failed to turn up any of those niceties and by 8:30, bird activity quieted down but I did manage to scope one more good bird to top off a memorable morning in Puntarenas. While scoping, I saw a dark shearwater flapping and then gliding but not like a small Galapagos Shearwater. This one was gliding in arcs, was bigger, and had a short tail. Sooty Shearwater!

If we had stayed longer, I bet more birds would have showed up. That’s how the birding in Puntarenas rolls but it would have also taken hours of watching, would have been a really long hot day.

We were happy to settle with four year birds, one of which was a major country tick, and at least three were lifers for Marilen. Back at home, I heard that an incredible 120 Blue-footed Boobies were seen from the ferry from Puntarenas along with two Peruvian Boobies. What’s next? I’m thinking Inca Tern and/or Guanay Cormorant. I can’t wait to go back, meditate on that ocean and see what I find!

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