The third edition of Think Stats is on its way to the printer! You can preorder now from Bookshop.org and Amazon (those are affiliate links), or if you can’t wait to get a paper copy, you can read the free, online version here. Here’s the new cover, still featuring a suspicious-looking archerfish. If you are not familiar with the previous editions, Think Stats is an introduction to practical methods for exploring and visualizing data, discovering relationships and trends, and communicating... Read More Read More The post Announcing Think Stats 3e appeared first on Probably Overthinking It.

February 27, 2024 The rains fell sometime after we went to bed and continued through the night, infiltrating our dreams. Light rain was still dripping from the trees as we awoke, and the dawn chorus was proportionally muted.  We had a quick breakfast and by 6:30 were on the small trail system behind the lodge. The mosquitoes were ferocious, and repellent only temporarily thinned them out, providing just a brief reprieve for a few minutes.  Birding was slow given the gloomy conditions but we tried our best to turn up a Blue-cheeked Jacamar or Rufous-necked Puffbird without success. Moises's only strategy was to loudly blast tapes of both species on repeat, so we weren't really surprised with the lack of a response. These types of tactics usually result in the target species being "taped out" in short order, and this is the main place at Muyuna Lodge where most birders try to find these respective species.  However, we finally connected with a Varzea Thrush. The views were brief as it was skittish in the understory, but we heard it singing and calling and I managed a few recordings.  We were also pleased to find a pair of Black-throated Antbirds. This species prefers dense understory growth, often near streams in the forest, and it is never easy to see well or photograph. I managed a few record shots of both the male and the female, representing the first meagre photos I have obtained of this species. If only my autofocus was working then I would have come away with much better results.   Black-throated Antbird (male) - Muyuna Lodge, Loreto, Peru Black-throated Antbird (female) - Muyuna Lodge, Loreto, Peru Later, we tracked down a pair of Coppery Titi Monkeys (Plecturocebus cupreus) that were duetting at the edge of the forest. In Amazonia there are numerous species of titi monkeys, each separated by range. This species was a new one for us - they are only found in the western Amazon basin in Peru and western Brazil.  Coppery Titi (Plecturocebus cupreus) - Muyuna Lodge, Loreto, Peru While the persistent rain may have made birding a little tough, there are certain other types of animals that thrive in these conditions. One particular group are the coral snakes. Laura and I have been fortunate over the years to have encountered numerous coral snakes - we are now up to seven species - but each encounter is never predictable and is to be cherished. Sometimes, heavy rains slightly increase the odds of encountering one. These snakes are typically fossorial, meaning that they spend much of their time living and hunting underground. Heavy rains may temporarily flood them out and bring them to the surface.  All three of us noticed the snake around the same time. "Coral snake!" Evidently the night's rains had stimulated this one to leave its subterranean retreat. This was a subadult Western Ribbon Coralsnake (Micrurus helleri). It was quite feisty and tried to make a quick escape, though we cornered it on the trail so that we could study it for a few minutes. I managed a few poor phone photos in the dim understory, but its erratic movements and the low light levels meant that I was unable to take any good photos with my telephoto. Unfortunately, my macro lens was resting safely back in our room.  Western Ribbon Coralsnake (Micrurus helleri) - Muyuna Lodge, Loreto, Peru Still, even without amazing photos we were ecstatic to have found a new species of coral snake for us! It made us forget about the hungry mosquitoes for a few minutes.  Western Ribbon Coralsnake (Micrurus helleri) - Muyuna Lodge, Loreto, Peru Next up were these photogenic Cream-colored Woodpeckers near their nesting cavity. The diversity of colours found in Neotropical woodpeckers is high, and the Cream-colored is a flashy one.  Cream-colored Woodpeckers - Muyuna Lodge, Loreto, Peru We also turned up this interesting little lizard. This is Cercosaurus argulus, the Elegent Eyed Lizard. This is a rarely seen semi-arboreal species, but we were fortunate in that this individual was foraging in the leaf litter. This is a shade-loving lizard that is rarely found in open sunny conditions.  Elegant Eyed Lizard (Cercosaurus argulus) - Muyuna Lodge, Loreto, Peru Laura spotted this Blue-lipped Tree Lizard (Plica umbra) perched on top of a tree buttress. This species seems to be relatively common and easy to encounter; they are usually perched 1-2 meters off the ground and are somewhat conspicuous.  Blue-lipped Tree Lizard (Plica umbra) - Muyuna Lodge, Loreto, Peru By mid-morning we returned to the lodge. The sun was now trying to burn through the thick clouds and bird activity was increasing. It was time to head out onto the water for a couple of hours before lunch time.   We were still on the lookout for a few species - namely, the Purple-throated Cotinga - but secondary targets included Wing-barred Seedeater and Gray-chested Greenlet. We slowly cruised along the quiet waterways, scanning the tops of the lush vegetation for perched cotingas. Alas, we were unsuccessful with the primary target.  However, luck was on our side with the other two species. We heard a singing Wing-barred Seedeater and while trying to to track it down, a Gray-chested Greenlet vocalized from the other side of the wetland! Quickly, both species were "in the bag".  Wing-barred Seedeater - Muyuna Lodge, Loreto, Peru Wing-barred Seedeater - Muyuna Lodge, Loreto, Peru The Gray-chested Greenlet is a widespread species of Amazonia, usually living in flooded forest. It is more localized in the western part of its range which may explain why Laura and I had never seen one before.  Gray-chested Greenlet - Muyuna Lodge, Loreto, Peru We headed back to the lodge, our spirits lifted after a productive boat trip.  Laura and I were eager to continue exploring, especially since the morning's birding had been relatively slow with all the rain. Bird activity was still high even at midday as the clouds hadn't disappeared, but Moises was not at all eager to head back out. It took some convincing to have him relent and agree to a 2 PM departure time, instead of the usual 3 PM. The joys of having to be stuck with a guide, especially one who was just going through the motions.  Riverside habitat - Muyuna Lodge, Loreto, Peru Our strategy this afternoon was similar to the pre-lunch boat trip. We would cruise slowly along vegetation-choked waterways, scanning the treetops for the cotinga. We had a brief moment of excitement when a female cotinga was found feeding in a fruiting tree. Alas, my terrible record photos confirmed that it was "just" a Plum-throated Cotinga. A great bird, but not the one we were hoping for! Plum-throated Cotinga (female) - Muyuna Lodge, Loreto, Peru Even without a Purple-throated Cotinga we really enjoyed our time on the water. Birding was relaxed and productive, with hardly a dull moment. We tallied nearly double-digit species of parrot-types, several Muscovy Ducks, many ant-things and woodcreepers by voice, and quite a few terns, kingfishers and other birds typical of these wetland habitats. There were several Brown-throated Three-toed Sloths (Bradypus variegatus), and we discovered a Horned Screamer nest, home to a couple of baby "screamlets".  Brown-throated Three-toed Sloth (Bradypus variegatus) - Muyuna Lodge, Loreto, Peru Horned Screamers - Muyuna Lodge, Loreto, Peru As the sun set we tried listening for and playing tapes of Zigzag Heron to no avail. We cruised back to the lodge at dusk. Despite the slow morning, we had still managed to tally around 130 bird species. The diversity in the Amazon is amazing! Laura and I convinced Moises to head back out for a short boat cruise after dark. This time, we did not venture too far from the lodge, focusing on the frogs that were calling from thick vegetation along the edges of the channels.  Pygmy Hatchet-faced Frog (Sphaenorhynchus carneus) - Muyuna Lodge, Loreto, Peru Pygmy Hatchet-faced Frogs were one of the dominant voices. This was a new species for us, presumably because they prefer these semi-aquatic, marshy habitats that are not easy to reach (while staying dry) except by boat. Pygmy Hatchet-faced Frog (Sphaenorhynchus carneus) - Muyuna Lodge, Loreto, Peru We also noted several Dendropsophus tree frogs in the riverside vegetation as well. Some were left unidentified, though some were likely Dendropsophus triangulum, the Variable Clown Treefrog.  Dendropsophus sp. - Muyuna Lodge, Loreto, Peru Variable Clown Treefrog (Dendropsophus triangulum) - Muyuna Lodge, Loreto, Peru This particular individual appears to be Dendropsophus reticulatus, the Reticulated Treefrog.  Reticulated Treefrog (Dendropsophus reticulatus) - Muyuna Lodge, Loreto, Peru Of course there was a lot of other things of interest to point our flashlights at, including various insects and spiders. Below are some of the others. It was a lot of fun to take photos with my macro lens as it had working autofocus - a nice change after struggling to manual-focus with my telephoto lens during the day.  Ancylometes sp. - Muyuna Lodge, Loreto, Peru Stagmatoptera binotata - Muyuna Lodge, Loreto, Peru Polka-dot Treefrog (Boana punctata) - Muyuna Lodge, Loreto, Peru Unidentified planthopper - Muyuna Lodge, Loreto, Peru Alpaida sp. - Muyuna Lodge, Loreto, Peru Cuernavaca longula - Muyuna Lodge, Loreto, Peru Tetrataenia surinama - Muyuna Lodge, Loreto, Peru We returned to the lodge not quite feeling ready for bed just yet. It was only 9 PM and, as it was our last night in the Amazon, we wanted to make the most of things. Laura and I set off on a quick night-hike on the trail system.  First up was a Southern Opossum (Didelphis marsupialis) that was lurking around some of the cabins.  Southern Opossum (Didelphis marsupialis) - Muyuna Lodge, Loreto, Peru Next, we braved the mosquitoes on the trail system in search of herps. We couldn't turn up any snakes, but quite a few frogs cooperated. Most were this species, the Red-snouted Treefrog (Scinax ruber), a widespread species found throughout most of South America and locally in the Caribbean and Central America.  Red-snouted Treefrog (Scinax ruber) - Muyuna Lodge, Loreto, Peru Red-snouted Treefrog (Scinax ruber) - Muyuna Lodge, Loreto, Peru Red-snouted Treefrog (Scinax ruber) - Muyuna Lodge, Loreto, Peru We also noted various Cane Toads (Rhinella marina) and Neotropical Grass Frogs (Leptodactylus sp.), as well as a few Sheep Frogs (Hamptophryne boliviana) that were calling from a flooded section.  Cane Toad (Rhinella marina) - Muyuna Lodge, Loreto, Peru Leptodactylus sp. - Muyuna Lodge, Loreto, Peru Sheep Frog (Hamptophryne boliviana) - Muyuna Lodge, Loreto, Peru We spotted this Bridled Forest Gecko (Gonatodes humeralis) sleeping on some trailside vegetation, while a little further along was a gorgeous Yellow-banded Pinktoe Tarantula (Avicularia juruensis). Bridled Forest Gecko (Gonatodes humeralis) - Muyuna Lodge, Loreto, Peru Yellow-banded Pinktoe Tarantula (Avicularia juruensis) - Muyuna Lodge, Loreto, Peru Yellow-banded Pinktoe Tarantula (Avicularia juruensis) - Muyuna Lodge, Loreto, Peru As we were heading back to the lodge, my flashlight caught the eyeshine of a spiny rat in the genus Proechimys. These are some of the most abundant mammals in Amazonia (not including several bat species), but, because they are nocturnal, we haven't seen them too many times before.  Proechimys sp. - Muyuna Lodge, Loreto, Peru February 28, 2024 Our final day at Muyuna Lodge. We were up early this morning and under clear skies we motored northward to the Amazon River. Our goal this morning was to attempt to find the last river island specialty we needed in this part of the Amazon, the River Tyrannulet. This species isn't as localized as some of the other species we had already seen along river islands, yet it was still a big hole on our lists that I was eager to fill.  Luckily, it did not take us too long to find a pair of them. They came right in to playback, allowing us to have excellent views of them in the riverside vegetation. My photos leave much to be desired; they were moving too quickly for me to have much success at all with manual-focusing.  River Tyrannulet - Muyuna Lodge, Loreto, Peru Moises also took us to his guaranteed site for Sand-colored Nighthawk, as our only view had been of one flying over the river at dusk back at the ExplorNapo Lodge. We quickly found a roosting nightjar and Moises happily proclaimed that we had found a Sand-colored Nighthawk. The only problem, of course, was that it was a Band-tailed Nightjar, which is a common riverside species that we have seen on numerous occasions over the years. Moises wasn't too happy with me challenging his identification, but that is indeed what the bird was. Alas, we were unable to find any real Sand-colored Nighthawks.  Ladder-tailed Nightjar - Muyuna Lodge, Loreto, Peru Many birds were active along the main Amazon River. There were signs of the impending spring conditions in the northern hemisphere as well, as many dozens of Fork-tailed Flycatchers and Eastern Kingbirds were flocking together and heading upriver, alongside hundreds of migrant Barn and Bank Swallows.  Eastern Kingbird - Muyuna Lodge, Loreto, Peru We returned to the lodge by 9:30 for a late breakfast. Laura and I still had a couple of hours remaining until our departure time and so we went for a final walk on the trails behind the lodge. Perhaps the sunny conditions would make it easier to find our remaining targets, the Blue-cheeked Jacamar and Rufous-necked Puffbird.  Rutela lineola - Muyuna Lodge, Loreto, Peru Unidentified brush-footed butterfly (family Nymphalidae) - Muyuna Lodge, Loreto, Peru Bird activity was the best we had seen it on these trails and we even found a few mixed flocks to pick through. Butterflies and lizards were also active.  Metamorpha elissa - Muyuna Lodge, Loreto, Peru Bridled Forest Gecko (Gonatodes humeralis) - Muyuna Lodge, Loreto, Peru Unidentified clearwing butterfly (tribe Ithomiini) - Muyuna Lodge, Loreto, Peru Agyrtidia uranophila - Muyuna Lodge, Loreto, Peru We returned to the lodge having had a very nice walk behind the trail system, even if the main target birds refused to cooperate. By the time we packed up and left Muyuna, our eBird checklist had reached 100 species for the morning.  Despite the difficulties that we had working with Moises, we still had a really nice visit at Muyuna Lodge. Finding our main target (the Wattled Curassow) on the first morning was a mega highlight. Herps were plentiful and we finished with five species of snakes, including a lifer coral snake. We also found some really interesting lizards including several Northern Caiman Lizards, a species I have wanted to see ever since I was a herp-obsessed teenager. And birding by boat along mega-diverse waterways, with a light breeze cooling us down, was a nice change of pace from slogging it along muddy trails with high temperatures and humidity. Muyuna Lodge is very comfortable and the staff are friendly and accommodating, while the food was excellent. This is a beautiful corner of the world and I hope to return one day.

But everyone wishes they weren't!

February 26, 2024 As dawn broke, Laura, Moises and I slowly cruised along a quiet watercourse. The dawn chorus was active and included species like Ferruginous Pygmy-Owl, Zimmer's Woodcreeper and Black-tailed Antbird, but I stayed focused on the treeline, hoping that a curassow-shaped bird would appear.  The dawn chorus quieted as the sun rose above the horizon. Early morning is the best time to find the curassow, and we were running out of time.  Domain of the Wattled Curassow - Muyuna Lodge, Loreto, Peru And there it was! It was the bright red bill that first caught my attention and 0.05 seconds later, my brain registered that I was staring at a female Wattled Curassow. Wattled Curassow - Muyuna Lodge, Loreto, Peru But it was better than I had imagined - the female was accompanied by a tiny chick! For a few magical minutes we watched the duo in their element.  Wattled Curassow chick - Muyuna Lodge, Loreto, Peru Wattled Curassow chick - Muyuna Lodge, Loreto, Peru Wattled Curassows are closely associated with these rivers in the western Amazon basin and that has led to their downfall. The rivers are the highways, and curassows have a lot of meat. But in a few areas like here, hunting of the curassows does not occur and encounters with this secretive species are possible. The curassows like feeding on the fruits of mahogany trees that line the watercourses, and that is likely what this female was on the hunt for.  Wattled Currasow - Muyuna Lodge, Loreto, Peru We were on cloud nine after such an epic start to the day! I was pleased that I even managed some mostly in-focus photos with my broken lens.  For the next few hours we cruised around by boat, checking out different waterways in search of some of our target birds. We were successful with Black-tailed Antbird and Short-tailed Parrot.  Black-tailed Antbird - Muyuna Lodge, Loreto, Peru Short-tailed Parrot - Muyuna Lodge, Loreto, Peru It was a very birdy morning and we cleared the hundred species mark before returning to the lodge for breakfast.  Bluish-fronted Jacamar - Muyuna Lodge, Loreto, Peru Black-tailed Tityra - Muyuna Lodge, Loreto, Peru Proboscis Bat (Rhynchonycteris nasa) - Muyuna Lodge, Loreto, Peru After breakfast, we searched by boat for some of the few remaining target birds I had in mind such as Purple-throated Cotinga, Gray-eyed Greenlet and Wing-barred Seedeater, but were unsuccessful.  Unidentified katydid - Muyuna Lodge, Loreto, Peru We were also on the lookout for Dusky-billed Parrotlets, a potential lifer for Laura and a new photographed bird for me. Moises claimed sightings on a few occasions, but each time my photos revealed that they were the more expected Riparian Parrotlets.  Band-tailed Antbird - Muyuna Lodge, Loreto, Peru At one point during the afternoon we entered an area of higher ground where there was a small walking trail. After spending most of the day in a boat it felt great to feel the earth beneath our boots, even though this meant that we were accompanied by a swarm of mosquitoes. Amazonian Trogon - Muyuna Lodge, Loreto, Peru Methona confusa - Muyuna Lodge, Loreto, Peru We found several groups of Eastern Pygmy Marmosets, one of the smallest species of monkey! Eastern Pygmy Marmoset (Cebuella niveiventris) - Muyuna Lodge, Loreto, Peru Eastern Pygmy Marmoset (Cebuella niveiventris) - Muyuna Lodge, Loreto, Peru Our guide, Moises had a stake-out for Nancy Ma's Night-Monkey (Aotus nancymai) that was visible from the main watercourse.  Nancy Ma's Night-Monkey (Aotus nancymai) - Muyuna Lodge, Loreto, Peru During the mid-afternoon, Moises took us down a channel choked with vegetation to look for some herps. We kept a close eye on the vegetation until Laura spotted the first snake, as she is known to do! Giant Parrot Snake (Leptophis ahaetulla nigromarginatus) - Muyuna Lodge, Loreto, Peru While we have seen this widespread species before, this was a new subspecies for us. The extensive black markings between the scales are quite distinctive.  Giant Parrot Snake (Leptophis ahaetulla nigromarginatus) - Muyuna Lodge, Loreto, Peru Even better than the parrot snake was this next species: a Northern Caiman Lizard (Dracaena guianensis)! I have wanted to see this huge species of lizard for many years but had never gotten lucky. As the name suggests, particularly large individuals somewhat resemble caimans, and they share similar aquatic habitats. Caiman lizards feed on snails, fish, amphibians and other creatures that they find underwater.  Northern Caiman Lizard (Dracaena guianensis) - Muyuna Lodge, Loreto, Peru Northern Caiman Lizard (Dracaena guianensis) - Muyuna Lodge, Loreto, Peru As the sun set, we found ourselves slowly paddling in a different wetland after another unsuccessful Purple-throated Cotinga search. We enjoyed watching a pair of Yellow-chinned Spinetails. This species is widespread in South America but is fairly localized in Peru.  Yellow-chinned Spinetail - Muyuna Lodge, Loreto, Peru You would be hard-pressed to find an activity that Laura likes more than a night-hike in the tropics, and tonight's walk was a good one. We only stayed out for a short while but came away with some nice sightings, including several snakes! Smoky Jungle Frog (Leptodactylus pentadactylus) - Muyuna Lodge, Loreto, Peru Ancylometes sp. - Muyuna Lodge, Loreto, Peru Unidentified net-casting spider (family Deinopidae) - Muyuna Lodge, Loreto, Peru Crowned False Boa (Pseudoboa coronata) - Muyuna Lodge, Loreto, Peru Pierella hortona - Muyuna Lodge, Loreto, Peru Leptodactylus sp. - Muyuna Lodge, Loreto, Peru Sais rosalia - Muyuna Lodge, Loreto, Peru Garden Tree Boa (Corallus hortulana) - Muyuna Lodge, Loreto, Peru I think my favourite sighting of the walk was this Slender Opossum (Marmosops sp.). It was extremely confiding and didn't mind my close approach for photos.  Slender Opossum (Marmoseps sp.) - Muyuna Lodge, Loreto, Peru Though they may resemble a rodent to some (Moises confidently identified it as an "Amazonian Mouse", whatever that is), these are actually a tiny genus of neotropical opossums, meaning that they are a marsupial. Slender opossums typically live in the viny, dense understory where they search for insects, arachnids, flowers and fruit.  Slender Opossum (Marmoseps sp.) - Muyuna Lodge, Loreto, Peru My final post from Peru will include our last couple of days at Muyuna Lodge.

When pigeons outnumber pigeonholes, some birds must double up. This obvious statement — and its inverse — have deep connections to many areas of math and computer science. The post How a Problem About Pigeons Powers Complexity Theory first appeared on Quanta Magazine