Time flies just like the migrants that zip through Costa Rica. Although I haven’t listened to the night skies as much as the previous year, the Spring Peeper-like notes of Swainson’s Thrushes have drifted down from the dark on several occasions. Fall migration has been happening here as it usually does- fast and furious. Thousands of Bank, Barn, and Cliff Swallows stream overhead in many parts of the country (how many Cave, Tree, and Violet-greens get missed?). Eastern Kingbirds, Scarlet Tanagers, and Red-eyed Vireos come through in droves. Although I haven’t been lucky enough to connect with cuckoos (can you tell that I’m a birder?), others have seen several Yellow-billed and Black-billed.
Thousands of shorebirds have been foraging in the rich estuarine habitats of the Nicoya Pensinsula since August and raptors are beginning to come through in numbers. Warblers also migrate through the country but we don’t get near as much diversity as the eastern USA and Mexico. Nevertheless, we make up for lesser numbers of warbler species with high numbers of Prothonotary, Blackburnian, Tennessee, and Canada Warblers to name a few. One of the other birds that passes through Costa Rica in fair numbers is that sky-blue rarity known as the Cerulean Warbler. In fact, so many are sighted during migration that Juan Diego Vargas and Ernesto Carman, a couple of young, eager Costa Rican ornithologists, are trying to figure out what the birds need in terms of food and habitat. They are also trying to understand why more Ceruleans seem to show up in a small area on the Caribbean flanks of Turrialba Volcano compared to other sites.
A little more than a month ago, I learned about many of their observations and hypotheses at Costa Rica’s first Biodiversity and Birding Festival. The festival was held at the Maquengue Finca and Hotel in Alegria, Siquirres and included lectures given by the Costa Rican “Don” of ornithology, Julio Sanchez, Juan Diego and Ernesto, guided birding walks at the nearby Las Brisas Reserve, and an excellent herp-focused night walk led by Brian Kubicki, one of Costa Rica’s foremost herpetologists.
The view from the hotel. Great site to watch migrant raptors!
The site of the festival wasn’t picked by chance. It sits smack in the middle of what appears to be a migration hotspot. According to field work carried out by Juan Diego and Ernesto, for whatever reason, the Las Brisas Reserve seems to be especially good for migrants, the Cerulean Warbler included. When they mentioned that it seems to be the best site to see Cerulean Warblers in Costa Rica, I admit that my first thought was “but who is checking other sites at similar elevations in Costa Rica?” However, that silent question was promptly answered when they explained that coordinated counts carried out at the same time in various similar sites have so far, always turned up far fewer Ceruleans than at the Las Brisas Reserve. Even counts on nearby ridges turned up no Ceruleans while several were seen at the Las Brisas Reserve. This isn’t to say that you can’t see Ceruleans elsewhere in the country, just that there seems to be more consistently seen at Las Brisas.
It’s a tough hypothesis to test but one thing is certain. The Las Brisas Reserve is the most guaranteed site for Cerulean Warbler in the country if visiting from the last two weeks in August to the first two weeks in September. The old secondary forests and ponds in the reserve also happen to be excellent birding in general with very impressive mixed flocks, and a healthy array of uncommon species. These be birds such as Uniform Crake, White-tipped Sicklebill, Crested Owl, Royal Flycatcher, Tawny-chested Flycatcher, and a host of other species.
Although I was only able to partake in festival activities on Saturday evening and Sunday morning, here are some of the highlights that I witnessed:
- Mississippi Kites: As in flocks of these graceful raptors flying by at eye level and kettling overhead. I could have sat back and watched their airborne antics for days while trying to pick out vagrant swallow species from the constant stream of Hirundines that zipped by from north to south.
- Ernesto and Juan Diego’s Cerulean Warbler Project talk: How often do you get to hear about the findings of field ornithologists studying Cerulean Warblers as they migrate through Costa Rica? Yeah, like never so this was a real treat! One interesting hypothesis they have is that Ceruleans may be migrating straight from the highlands of Belize and Guatemala to the Las Brisas Reserve in Costa Rica and are using that as an important stop over point. This idea is in part based on only seeing Ceruleans at Las Brisas after 10 AM. Since that mid-morning hour coincides with the amount of time it would take for Ceruleans to fly from Guatemala and Belize, they wonder if the birds may be flying non-stop from those places to the Las Brisas area. Now before you say that the birds are just being inconspicuous, keep in mind that the people making these statements are highly competent field birders (trust me on that!) who have spent hundreds of hours at Las Brisas and elsewhere, nearly always starting their observations at dawn. With that in mind, one does have to wonder why they only see Ceruleans after 10 in the morning.
- The night walk at Las Brisas: The ponds at the reserve make it one of the best sites for frogs in Costa Rica. We saw something like 8 species, a Cat-eyed Snake eating a frog, and heard Tropical Screech, Mottled, and Crested Owls.
A cool Cate-eyed Snake.
- The Cerulean Warbler count of course!: Our little team was tasked with looking for Ceruleans at middle elevations up the road from the hotel. The only one we saw was a female observed at the lower part of our counting area (and which seems to coincide with the upper elevational limits of their range) but we also had birds like Collared Trogon, Spangle-cheeked, Black and Yellow, Tawny-crested, Speckled, and other tanagers, Dark Pewee, several Black-bellied Hummingbirds, White-bellied Mountain-Gem, and Rufous-browed Tyrannulet. Much of the road passes near a forested canyon and the higher parts access good middle elevation forest. I would have loved to have camped out in those forests! Another highlight of the count was meeting a local farming couple who were enthusiastic about and interested in protecting biodiversity. People like them give me hope for the future and when they described having seen a male Lovely Cotinga, we realized that the area has a lot of birding potential!
One of the friendliest Collared Trogons I have ever known.
- The participants: Around 70 people showed up for the festival and all of them were people who reside in Costa Rica.
Some participants of the 2012 festival.
Although this year’s festival was in Spanish, the festival organizers plan on holding a a bigger one next year that also includes English speakers. Expect to see a lot more than Cerulean Warblers, more birding trips, and more celebration of biodiversity!