Explorations of an Ecologist: Los Amigos Biological Station: Part 2

September 21, 2022

Laura and I had arranged with the cook to have a packed breakfast this morning. This turned out to be a great idea. The day was another scorcher, reaching a high of 36 degrees Celsius, and we appreciated having the freedom to explore the trails early in the morning without having to return during peak birding hours for breakfast.

Pygmy Antwren - Los Amigos Biological Station, Madre de Díos, Peru

We walked down Trail 10 at dawn, following it all the way to the end where a viewpoint overlooked Río Los Amigos. Early highlights included a lifer monkey (Shock-headed Capuchin) and our first ever views of a Collared Puffbird.

Shock-headed Capuchin - Los Amigos Biological Station, Madre de Díos, Peru

I was just as excited to see a Long-tailed Woodcreeper. To the average person that would seem odd, as it is basically a streaky brown bird that isn't even that memorable amongst the other woodcreepers. But it is a species which I had searched for unsuccessfully on many occasions, and my only previous encounter with one had been by voice. The Amazonian Long-tailed Woodcreepers likely represent a different species than the Central American subspecies.

Long-tailed Woodcreeper - Los Amigos Biological Station, Madre de Díos, Peru

Bird activity at Río Los Amigos was high, especially with parrot-types. The Amazonian Parrotlet is one of the specialties of Los Amigos Biological Station and we watched a group of them fly over here. This ended up as our only decent sighting of this scarce species.

Amazonian Parrotlet - Los Amigos Biological Station, Madre de Díos, Peru

We also watched a single Curl-crested Aracari fly over the river, though it disappeared and we never saw it again. This was one of my most-wanted birds for Los Amigos. We would have to wait a few more days for satisfying looks at some, however.

Curl-crested Aracari - Los Amigos Biological Station, Madre de Díos, Peru

Our final memorable sightings at the river overlook were a Horned Screamer along the river and a Chestnut-crowned Foliage-gleaner in dense vegetation beside the viewpoint.

Río Los Amigos, Madre de Díos, Peru

We turned off Trail 10 onto Trail 25, following the ridge for a while and then descending into bottomland forest. For the rest of the morning we tromped around the "lower terrace", investigating one of the oxbows (Cocha Lobo) and birding the rich forests here.

Purús Red Howler Monkey - Los Amigos Biological Station, Madre de Díos, Peru

Band-tailed Manakin - Los Amigos Biological Station, Madre de Díos, Peru

Birding highlights were many, though as you can tell from the lack of photo quality in this post, it was not necessarily a good photography day. Some of the new bird species for one or both of us included Rusty-belted Tapaculo, Chestnut-shouldered Antwren, Dull-capped Attila, Dusky-tailed Flatbill and Dusky-capped Greenlet.

Dull-capped Attila - Los Amigos Biological Station, Madre de Díos, Peru

A bit of speculative playback in a dense bamboo grove produced our lifer Striated Antbird. This species is quite attractive and surprised us by hopping out into the open, completely unobscured! Of course, I had to go and blow the photos...

Striated Antbird - Los Amigos Biological Station, Madre de Díos, Peru

We enjoyed spectacular views of a pair of Plumbeous Antbirds, our first sighting of this commonly heard species of varzea and riverine forest.

Plumbeous Antbird - Los Amigos Biological Station, Madre de Díos, Peru

From reading these posts it may seem that birding in Amazonian forests is constant, with birds around every bend. The truth is that the conditions are challenging at best, even at a site like Los Amigos where the high diversity of habitats in a small geographic area make it possible to encounter a wide diversity of species. Even when one comes across a mixed flock, while it is exciting, it is by no means easy. One has to accept that they may only identify a fraction of the birds traveling in the flock. The high temperatures today were not helping our cause either and we went through long stretches with barely a bird to be found. During these periods I often allowed myself to be distracted by the insect life, of which there is almost always something of interest around.

Mecistogaster ornata - Los Amigos Biological Station, Madre de Díos, Peru

Another vantage point of Río Los Amigos gave us a chance to observe several turtles. I later identified these as Yellow-headed Sidenecks (Podocnemis unifilis), a widespread Amazonian species.

Podocnemis unifilis - Los Amigos Biological Station, Madre de Díos, Peru

We trudged along for a while. Eventually, the monotony was broken by a flurry of bird activity in the trees above us. We did alright with this bird wave, identifying a nice variety of foliage-gleaners, woodcreepers, antwrens, flycatchers and more.

Rufous-tailed Foliage-gleaner - Los Amigos Biological Station, Madre de Díos, Peru

Buff-throated Woodcreeper - Los Amigos Biological Station, Madre de Díos, Peru

We savoured our first sighting of a male White-winged Shrike-Tanager. This species is often the leader of the mixed flocks and its incessant calls show the other birds which way to travel.

White-winged Shrike-Tanager - Los Amigos Biological Station, Madre de Díos, Peru

We had been on the trails pretty steadily for the first few days of our Los Amigos visit. Given the hot conditions and our fatigue, we took several hours off in the afternoon to rest. Finally, with less than two hours remaining until sunset, we walked down Trail 1, paralleling the former airstrip. The temperatures hadn't quite subsided but the sun's low angle provided a measure of relief.

Toppin's Titi - Los Amigos Biological Station, Madre de Díos, Peru

Birding was good as it always is along this trail, though activity wasn't particularly high. We added a few birds to our Peru lists including Eastern Kingbird and Ochre-bellied Flycatcher.

Crowned Slaty Flycatcher - Los Amigos Biological Station, Madre de Díos, Peru

Black-tailed Tityra - Los Amigos Biological Station, Madre de Díos, Peru

I strung up my moth sheet in the evening, picking a spot near the entrance of Trail 1. I find that I have much better luck with moths when I set up the light deep in the forest. Conventional wisdom states that installing the light in an open area is better because the light/sheet combo is more visible to insects, but my experience is the exact opposite. I think that there is greater value in bringing the light into the desired habitat. Perhaps some of these moths are unwilling to leave the forest, and will be more likely to investigate the light if it is found close to their preferred habitat. Additionally, there are often fewer midges, flies or other "undesirable" insects in nice forest habitats compared to open grassy sites. I don't have anything against flies or midges, but sometimes 10,000,000 of them on the sheet at once isn't exactly what I'm after!

Hypercompe - Los Amigos Biological Station, Madre de Díos, Peru

Belonoptera cancellata - Los Amigos Biological Station, Madre de Díos, Peru

The mothing was pretty good and I photographed around 70 species in the time before and after our night walk. Of course, I haven't actually gotten around to identifying these moths yet. Perhaps I will find the time during a wintery, February evening a year or two from now.

The night walk was rather productive despite us only staying out for an hour and a half. The highlight was this mature adult Tropical Flat Snake (Siphlophis compressus) that Laura spotted in a brush pile beside the trail. This was our third encounter with this gorgeous snake, following individuals in Ecuador in 2019 and Colombia earlier this year.