Explorations of an Ecologist: Chasing Endemics at Cerro Colorado

Laura and I overnighted near the town of San Felix. Lodging options are not great here, but we found an awesome property called Hostal Casa Las Lajas. Located just south of the Interamericana Highway, we had a comfortable room and access to a kitchen for only $20 for the night. The owner of the place is a German guy who has been living in Panama for several years, and he was very hospitable. A delicious restaurant was located next door. What more could you want?

The reason that we had chosen the rather obscure location of San Felix was its proximity to Cerro Colorado, located east of Fortuna in the Serranía de Tabasará. A number of birds in this mountain range have been isolated and over time have become distinct. Two of them are unique enough that they are classified as their own species: the Yellow-green Brushfinch and the Glow-throated Hummingbird.

Yellow-green Brushfinch habitat - Cerro Colorado area, Ngäbe-Buglé, Panama

The Yellow-green Brushfinch is pretty distinctive when compared to the Yellow-thighed Brushfinch found further west. The Glow-throated Hummingbird is a different story. If seen well, males can be distinguished from Scintillant Hummingbird, but females and immatures of these Selasphorus hummingbirds can be quite difficult or impossible to identify (there is some disagreement on the correct field marks). It seems that the vast majority of Selasphorus hummingbirds seen in this area are the females/immatures as well.

There happens to be a fair bit of confusion where the range of Scintillant ends and Glow-throated begins. There are only 15 "accepted" records of Glow-throated Hummingbird on eBird, to give you an idea of how difficult it is to find and confirm the identify of this species.

Interestingly, a population of Selasphorus hummingbirds currently considered Glow-throated Hummingbird can be found in the Cerro Hoya area, way down on the Azuero Peninsula. I'm not sure if anyone has completed genetic studies on these birds and compared them to the Cerro Colorado birds, but the distance between these two populations is quite substantial.

October 13, 2021

We were up before dawn and were soon on our way. To access the correct area, drive north of San Felix on the only paved road that continues out of town. The road deteriorates in sections, but eventually it drastically improves. The entire length is doable in a small rental car. It took us around 1 hour and 20 minutes to reach our destination, not including the 20 minutes I wasted by traveling down the wrong road in the town of Hato Chami. The vistas were beautiful as we climbed in elevation, though it was pretty disheartening to see the deforestation that has occurred in this region. A story repeated in many places around the world.

Cerro Colorado area, Ngäbe-Buglé, Panama

We parked our car in the small town of Entrada de Acha, which is pretty much at the end of the road. We parked at 8.510839, -81.787778 and asked one of the locals for permission to leave our vehicle here, which was granted. To access proper forest inhabitated by the brushfinch, one needs to hike up the gravel road from here towards the town of Ratón. Selasphorus hummingbirds are often noted from here as well, though it seems that Scintillant is more likely in this stretch.

The rain held off but the fog rolled in which quieted the bird activity. We still added a few species here and there, though it was hard to find birds that were not the ubiquitous Swainson's Thrush. I estimated 120 of this migrant species for my eBird checklist. There were probably many more. Laura and I were both a little sick of boarding the Swain Train by the end of the morning!

Birding the road to Ratón - Cerro Colorado area, Ngäbe-Buglé, Panama

Some of the montane species along our walk included Prong-billed Barbet, Yellowish Flycatcher, Slaty-backed Nightingale-Thrush, Collared Redstart, Black-faced Solitaire and Golden-browed Chlorophonia. Mountain Elaenias were abundant, their calls competing with the voices of many Silvery-throated Tapaculos.

Yellowish Flycatcher - Cerro Colorado area, Ngäbe-Buglé, Panama

We walked for several kilometres but had no success with the brushfinch. There were no Selasphorus hummingbirds around either. Perhaps, this was due to the time of year and lack of suitable flowering plants? The deforestation wasn't helping our cause, nor was the evidence of multiple landslides which had wiped out quite a bit of forest.

Cerro Colorado area, Ngäbe-Buglé, Panama

The Swainson's Thrushes were not the only common migrant bird species. Both Summer and Scarlet Tanager were present along with a smattering of Rose-breasted Grosbeak, Bay-breasted Warbler and Blackburnian Warbler.

Rose-breasted Grosbeak - Cerro Colorado area, Ngäbe-Buglé, Panama

We passed through one decent forest patch, though it lasted for only a 100 m stretch of road. At one point I thought I heard the brushfinch. Unfortunately, I could never confirm it amongst the chattering of Common Chlorospingus, and so we eventually continued on.

Unidentified flea beetle (and leafhopper) - Cerro Colorado area, Ngäbe-Buglé, Panama

Finally, at a distance of nearly 3.5 kilometers from our starting point, we found success in a better section of forest. A pair of Yellow-green Brushfinches! It was a tense moment or two before Laura was able to get me on them. They stayed high in the trees and the lighting was not great for photos, but for several minutes we enjoyed identifiable views of them through binoculars. Eventually, they came a little lower for much better views. Quite a different looking bird from the common Yellow-thighed Brushfinches that we had seen further west.

Yellow-green Brushfinch - Cerro Colorado area, Ngäbe-Buglé, Panama

For comparison, here is a photo of a Yellow-thighed Brushfinch from Costa Rica. I still have not managed a good photo of this species!

Yellow-thighed Brushfinch - Savegre Hotel, San José, Costa Rica

We retraced our steps now that our main target in the bag. Time was already starting to run out on us since we had planned a 4 hour drive that afternoon.

Birding the road to Ratón - Cerro Colorado area, Ngäbe-Buglé, Panama

A short search for the hummingbird down a nearby road was in order once we had collected the car. Even though I thought our odds at finding an identifiable Glow-throated Hummingbird was miniscule at best, I wanted to try an area where they had been reported on occasion: a paved road heading east towards Llano Tugrí. We had only made it a short distance towards the start of this road when a dead snake caught my attention. It was a shame to see that it was a beautiful Central American Coralsnake (Micrurus nigrocinctus), the only one that either Laura or I had seen. Still, an opportunity to study this species up close.

Road-killed Micrurus nigrocinctus - Cerro Colorado area, Ngäbe-Buglé, Panama

Our search for the Glow-throated Hummingbirds was unsuccessful. In fact, no Selasphorus hummingbirds of any kind were noted. Maybe one day I will return and spend a few days in this area with a local guide, or perhaps I will try to organize a Cerro Hoya expedition. Something to think about for future trips!

For further reading on birding this area and the Glow-throated Hummingbird, check out these links:

https://birdsofpassage.wordpress.com/2014/08/15/glow-throated-hummingbird-yellow-green-finch/

http://www.xenornis.com/2012/02/birding-cerro-colorado-report-by-bill.html

http://www.xenornis.com/2013/08/cerro-santiago-and-cerro-colorado.html

http://janbirdingblog.blogspot.com/2013/08/cerro-santiagos-selasphorus-hummingbirds.html

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Laura and I made the long drive back down the mountain, then eastwards along the Interamericana Highway to the start of the Azuero Peninsula. We had two nights booked at Hotel Heliconia, and we had organized a boat trip for the following day to Coiba Island with Hotel Heliconia's owner, Kees Groenendijk. Following a delicious dinner served by Kees that evening, I strung up the moth sheet in the yard. We only lasted at the sheet for a short while before exhaustion set in, but several interesting moths appeared.