Tuesday 2 April 2024

A Month In Northern Peru, Part 5: The Marañón Valley (February 7, 2024)

February 7, 2024

The Marañón Valley is one of the most important biogeographical boundaries in the Andes. Situated in northwestern Peru, the valley follows the Marañón River which flows northward across plateaus in the Andes. After cutting through a very deep, heavily eroded valley (the Marañón Valley), the Marañón River makes a sharp turn to the east and flows across western Amazonia. Eventually, the Marañón River meets up with the Ucayali River, and it is at this confluence where most cartographers chart the Amazon River as beginning. In one sense, however, you could argue that the source of the Amazon River is actually the source of the Marañón River, beginning high in the Andes about 160 kilometres from Lima, Peru. 

The steep-sided Marañón Valley is an important biogeographic boundary because its unique climate acts as a barrier. Due to rain shadow effects, the Marañón Valley is rather hot and dry. If you are a species living in the cool, rain-filled Andes, you are probably not going to venture down into an arid, cacti-laden valley to reach humid mountains on the other side. Additionally, the Marañón Valley and its xeric habitats are isolated from other regions with similar conditions, so quite a few of the species found here have evolved into new species over time. 

Marañón Valley, Cajamarca, Peru

February 7 was a day that I had been looking forward to for a while. We would begin in Celendín, gain elevation as we approached the humid western rim of the Marañón Valley, then spend the morning descending as the environment became drier and sunnier. We would cross over the Marañón River and continue up the east side, gaining elevation and watching the vegetation "green up" as we traveled. By the late afternoon, we hoped to find ourselves in Leymebamba. Not only would we observe the changes in the plant life due to the climatic conditions, but we would have a chance to search for quite a few bird species that are only found in the Marañón Valley. 

Marañón Valley, Cajamarca, Peru

We left before sunrise and the rain fell steadily as I drove the Rav4 towards the western rim of the Marañón Valley. Almost immediately after crossing over the pass, the rain abated. As we descended, the fog slowly but stubbornly dissipated, providing scenic views of the valley. I had to be careful to keep my eyes on the single-lane road during this steep section. On a handful of occasions I had to backup to a slightly wider section to allow space for an oncoming vehicle. The fog at dawn didn't help matters.

Marañón Valley, Cajamarca, Peru

After an hour of driving, I turned off onto a dirt track for a combined breakfast and birding stop. My main target came through, in the form of several Gray-winged Inca-Finches singing from up the hillside!

Gray-winged Inca-Finch - Marañón Valley, Cajamarca, Peru

One of them flew right down to our level, allowing us to really study its plumage through our binoculars. Quite a difference from the Buff-bridled Inca-Finch that we had seen the previous day. 

Gray-winged Inca-Finch - Marañón Valley, Cajamarca, Peru

Gray-winged Inca-Finch - Marañón Valley, Cajamarca, Peru

Having refuelled with breakfast and with a lifer, we continued down to the next site, which is well-known among birders and referred to as Endemic Point. There aren't many places to leave the roadside in these steep upper sections of the valley, so each location happens to be a birding hotspot. 

Roadside birding near Endemic Point, Cajamarca, Peru

Immediately after opening the car doors we heard a Chestnut-backed Thornbird singing away. This species is endemic to the upper Marañón Valley, and it has a highly restricted range. This particular road, down the west slope of the Marañón Valley from Celendín to Balsas, is the only accessible place where the Chestnut-backed Thornbird can be seen with any regularity. 

Chestnut-backed Thornbird - Endemic Point, Marañón Valley, Cajamarca, Peru

We found our first Marañón Thrushes, though they were being skulky in the dense vegetation beside the road. This Tumbes Pewee was a little more cooperative. 

Tumbes Pewee - Endemic Point, Marañón Valley, Cajamarca, Peru

We found the side trail leaving the main road and were quite happy to get away from all the honking vehicles. 

View from Endemic Point, Marañón Valley, Cajamarca, Peru

Additional new species revealed themselves now that we were off of the main road. We found a pair of hyperactive Buff-bellied Tanagers. This is an attractive species that bears some similarities to the widespread Rufous-chested Tanager, but with lighter overall plumage, a pale face, and no obvious white belly patch. 

Buff-bellied Tanager - Endemic Point, Marañón Valley, Cajamarca, Peru

Buff-bellied Tanager - Endemic Point, Marañón Valley, Cajamarca, Peru

Yet another Marañón endemic species appeared in the form of a Peruvian Pigeon. Several blasted by us down the mountain, while one obliged our request by perching on a distant snag. 

Peruvian Pigeon - Endemic Point, Marañón Valley, Cajamarca, Peru

Peruvian Pigeon - Endemic Point, Marañón Valley, Cajamarca, Peru

Finally, with a bit of patience, we were rewarded with excellent views of a Marañón Thrush. My photos were partially obscured but I was happy with what I managed, given the circumstances. 

Marañón Thrush - Endemic Point, Marañón Valley, Cajamarca, Peru

I would be remiss to not mention the plant life at Endemic Point. At this elevation, a significant amount of rain still falls, and this is reflected in the diversity of the lush vegetation. 

Govenia sp. - Endemic Point, Marañón Valley, Cajamarca, Peru

Dalechampia aristolochiifolia - Endemic Point, Marañón Valley, Cajamarca, Peru

Salvia sp. - Marañón Valley, Cajamarca, Peru

Ennealophus foliosus - Endemic Point, Marañón Valley, Cajamarca, Peru

Laura and I had succeeded with most of our bird targets for the morning, but the most important one remained. The Yellow-faced Parrotlet is often the most difficult of the Upper Marañón Valley endemics, but we had the rest of the morning (and afternoon, if it came down to it) to search for this beautiful green, yellow and blue gem. 

Marañón Valley, Cajamarca, Peru

Yellow-faced Parrotlets are most commonly seen in the arid lower parts of the valley, especially areas with a lot of cacti, closer to the Marañón River. They can be difficult to locate, though, since they are a goldfinch-sized, greenish-yellow bird that likes to perch on greenish-yellow cacti. Fortunately, like all parrotlets, they have distinctive vocalizations that are uttered frequently. 

Marañón Valley, Cajamarca, Peru

Our strategy was simple. We would drive slowly with the windows open, listening for the lively calls of the parrotlets. Whenever there was a pull-off, we would stop the car and bird from the roadside for a few minutes before continuing on. 

Our first stop didn't produce the parrotlets, but we found some Buff-bridled Inca-Finches, a Squirrel Cuckoo, the Marañón subspecies of Tropical Gnatcatcher, and a new lizard for us. 

Buff-bridled Inca-Finch - Marañón Valley, Cajamarca, Peru

Squirrel Cuckoo - Marañón Valley, Cajamarca, Peru

"Marañón" Tropical Gnatcatcher - Marañón Valley, Cajamarca, Peru

Microlophus arenarius - Marañón Valley, Cajamarca, Peru

Our next couple of stops were unsuccessful with the parrotlet but we kept at it. At one point, Laura thought she heard something "interesting" out of her window. There wasn't a safe place to pull over, so I dropped Laura off and continued along, eventually finding a suitable pull-off. I ran back up the road towards her when we heard it - parrotlets calling from down in the valley!

One of them seemed to be quite close and I soon spotted it on the top of a cactus. We walked up the hill until we had a clear window. 

Yellow-faced Parrotlet - Marañón Valley, Cajamarca, Peru

We were ecstatic, not only because we had found the parrotlets, but because we had below-eye-level views of one feeding from a cactus in perfect light!

Yellow-faced Parrotlet - Marañón Valley, Cajamarca, Peru

Our strategy of driving slowly and listening had paid off, but we were also fortunate in that it was an overcast, windless day. Birds were still active late into the morning, while the lack of a breeze made for easy listening conditions. 

Yellow-faced Parrotlet - Marañón Valley, Cajamarca, Peru

We continued our drive towards the Marañón River, when it happened again - this time it was me hearing the parrotlets out of my window. Again we stopped, and again we were treated to amazing views. We ended up finding yet another parrotlet at the bottom of the valley near the Marañón River. What luck!

Polydamas Swallowtail (Battus polydamas) - Marañón Valley, Cajamarca, Peru

Having seen all of the birds we had hoped to find, the rest of the day was devoted to driving eastward up the other side of the valley. There were several additional target species we had in mind from the humid, scrubby environments high up in the mountains. 

Marañón Valley, Amazonas, Peru

The first section of the drive was a little bit tricky. The road was only wide enough for one vehicle, and the sheer drop-off beside the road was a little too close for comfort. Though it was a bit nerve-wracking each time we encountered another vehicle, this is a good thing when traveling on a sketchy mountain road in the Andes. If no vehicles are coming from the other direction, it often means that there is a landslide impeding traffic. I was a bit relieved with each passing bus even though it often required creative driving maneuvers to pass the vehicle. 

Laura and I found a dead snake on the road which was a little surprising, given how infrequently we encountered vehicles. It must have picked a most unfortunate time to attempt to cross the road. This is likely a type of racer in the genus Mastigodryas, possibly Heath's Tropical Racer (Mastigodryas heathii). If you wish to see a picture of it, here is a link to my iNaturalist observation. 

We stopped for lunch at a small family run place, one of only two restaurants that we saw between the Marañón River and Leymebamba. Continuing on, the vegetation changed rapidly from arid, cacti-dominated scrub, to grasslands with scattered shrubs, eventually to humid, stunted montane forest. The wind had really picked up, as did occasional bands of rain. The road, while technically still paved, was in disrepair due to the effects of the frequent rain. There were more potholes than actual road in many areas. 

 Marañón Valley, Amazonas, Peru

Laura and I stopped at a few ravines, where the flowing stream encouraged a variety of shrubs and bamboo to flourish. This is the ideal habitat for the Russet-mantled Softtail, yet another range-restricted species. 

The wind and rain did not help matters and our luck had run dry, though with time we teased a few species out of the woodwork. We were pleased to have our first great views of a Rainbow Starfrontlet. An impressive hummingbird!

Rainbow Starfrontlet - Marañón Valley, Amazonas, Peru

Several birding stops later, we still had not found the softtail nor had we encountered Neblina or Utcubamba Tapaculos or any antpittas. However, as we crossed over the Abra Calla Calla mountain pass the wind abated and the rain stopped. By the time we reached Abra Barro Negro, the birding conditions were perfect. 

Marañón Valley, Amazonas, Peru

Band-tailed Pigeon - Marañón Valley, Amazonas, Peru

At one scenic bridge we immediately heard a response from a pair of Utcubamba Tapaculos. With some patience, we had incredible views of one out in the open, though it was much too quick for my camera. I did manage a few photos of it singing from deep within a bush. 

Utcubamba Tapaculo - Marañón Valley, Amazonas, Peru

We heard a Chachapoyas Antpitta here, though it was too far up the slope to try to see. We also found our first Russet-mantled Softtail as well, a big highlight for the two of us. Just like that, our afternoon luck had turned. 

Russet-mantled Softtail - Marañón Valley, Amazonas, Peru

We considered making additional stops to try for a Leymebamba Antpitta, as it is a species we have heard several times, but had never seen. But the day was getting long and we still had an hour of driving to reach the town of Leymebamba, so we opted against this. 

It had been a long day on the road when we reached our hotel - Hotel El Duke, which we highly recommend - but it had been a great day. 

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