Consortium of Color

Every bird has a consortium of proteins and pigments in their feathers that work together to produce a pattern of colors.  The birds that we catch during our studies on the Nicoya Peninsula demonstrate the astonishing variety of patterns and colors that makes tropical birds famous for their good looks.  This winter I have been taking macro photos of the plumages of some of the more ornate birds we encounter at our banding stations.  Without delving into the explanations behind the production of these patterns and colors - a topic for a different post - I take this opportunity to share some of the most stunning (at least by human standards) plumages we encounter.

Male Barred Antshrike

Turquoise-browed Motmot

Rump and central tail feathers of a male Black-headed Trogon

Crown feathers of a male Long-billed Starthroat

Gorget of a male Long-billed Starthroat

 Below are photos of each of the birds featured above, in order of appearance.  

 

 

Out-of-bounds

Despite Costa Rica having a relatively well-studied bird fauna, our five years of field work on the eastern Nicoya Peninsula have yielded many surprising discoveries.  Among the most interesting are our encounters with bird species which, according to the literature, are not expected to occur on the Nicoya Peninsula at all, or at least during the period we visit each year.  Our most recent three-day banding session at the Reserva Natural Absoluta Cabo Blanco provided several examples of how even our basic knowledge of bird distributions needs quite a bit more work.

One species whose capture this morning represented our fourth encounter is the Ruddy Quail-Dove (Geotrygon montana).   The species' Costa Rica distribution as described by The Birds of Costa Rica (by Richard Garrigues and Robert Dean) and BirdLife International (http://www.birdlife.org/datazone/species/factsheet/22690966) extends northward along the Pacific coast only to the Rio Tárcoles.  The Tárcoles lies directly east of the Nicoya Peninsula on the mainland.  A literal (albeit small) gulf separates our encounters of this species with its described distribution.

Female Ruddy Quail-Dove (Geotrygon montata) banded on December 22

Male Ruddy Quail-Dove spotted in January 13, 2014

Another bird encountered this morning that is much more familiar to us North American bird banders is the Wood Thrush (Hylocichla mustelina).  The literature describing the winter range of this species in Costa Rica is incongruous; the most recent edition of The Birds of Costa Rica, depicts the species as being absent from the Nicoya Peninsula, while several reputable sources have published that the species is absent from the Pacific Slope of Costa Rica altogether.  A few other sources (including BirdLife International) correctly include the Nicoya Peninsula in their maps of this species' distribution.  To date we had captured 18 Wood Thrushes at our three banding sites on the Nicoya Peninsula, and today Cabo Blanco produced an additional three. 

Two Wood Thrushes banded on December 22 at Cabo Blanco

Finally, instead of a spacial discrepancy, we have a temporal one; the Swainson's Thrush, according to the most recent edition of The Birds of Costa Rica (Garrigues and Dean, 2014) and the original A Guide to the Birds of Costa Rica (Styles and Skutch, 1989), does occur throughout most of Costa Rica, but only as a passage migrant.  They are said to pass through Costa Rica on their southbound migration in September-November and again on their northbound migration in March-May, but are supposedly absent in December, January, and February.  Apparently the Swainson's Thrush we captured this morning at Cabo Blanco had not read those books, nor had the 17 others we've captured since the project began in 2011.

NPARS's first Swainson's Thrush, banded in 2011

These three species captured this morning are on a list with several other out-of-range or otherwise unexpected bird species that we have encountered since the start of this project.  We find it amazing that even in a country so well-studied (speaking relatively and from a biological perspective), there is still so much to learn about the basic biology of its bird fauna.  We are truly privileged to work in a place with so much to discover.

Bienvenidos

After nearly a year away (and apart), the NPARS team is back together for another month-and-a-half of field work in the tropics.  This winter field season represents the fifth consecutive year of bird banding and research our first trip in 2011.  As we get settled in, we will periodically post updates of our field work, as well as anecdotes about living and working in the tropics.

This post is the first of several of the latter type.

Quite easily the best 'welcome back' we receive upon our return to the Nicoya Peninsula is the hummingbird spectacle at Finca Pura Vida.  The scene is chaotic and mesmerizing, involving hundreds of hummingbirds of nearly a dozen species buzzing around the feeders with dizzying speed.  I recorded the following video in 2014 of the feeding frenzy at Finca Pura Vida:

The main function of the feeders is to facilitate the capture of large numbers of hummingbirds for our research, since they provide us with sufficient sample sizes of these normally seldom-captured birds.  The hummingbird frenzy, however, has become as much a part of life here as the humidity.  Every day, from dawn to dusk, the frantic swarm drones away in the background.  We share a great sense of nostalgia for our hyperactive nectivorous friends, and it has become tradition for us to spend at least a few hours during our first morning back in Costa Rica enjoying and photographing them.

A tree full of Green-breasted Mango (Anthracothorax prevostii)

Male Green-breasted Mango (Anthracothorax prevostii)

It sure feels good to be back!

Nocturnal Creatures (Part II: Bats)

My home state of New Jersey (and its neighboring states) proudly boasts nine species of bats; six of these can be found within its borders year-round, while the other three are only with us during the warmer months of the year.

Costa Rica on the other hand has an astounding diversity of bats; to date, the list consists of 111 species!  This is more than all other Costa Rican mammal species combined, and is more than twice the number of bat species found in all of North America -- not bad for a country with less area than Lake Michigan!

Lesser Sac-winged Bats (Saccopteryx leptura) in a tree cavity

Our efforts to study neotropical owls (see Nocturnal Creatures Part I) have provided us with the exciting opportunity to get to know some of the many bat species on the eastern Nicoya Peninsula.  Whether we like it or not, setting up nets at night in the tropics inevitably results in encounters with bats.  Luckily, we like that just fine.  Some of the bat species we have captured alongside the owls we are studying have been truly spectacular; indeed, some of them are nearly as large as the owls themselves!

The Greater Spear-nosed Bat (Phyllostomus hastatus),
 the second-largest bat in Costa Rica

When we were on the first net check of our very first night of owl-netting, we approached a net containing one owl and two Greater Spear-nosed Bats (Phyllostomus hastatus, pictured above and below).  These bats are so large that, in the dim light cast by our headlamps on our approach, we thought they were owls!  The two bats had wingspans of sixteen and seventeen inches, just a few inches shy of the wingspan of the Pacific Screech-Owl that had been captured alongside them.

Greater Spear-nosed Bat (Phyllostomus hastatus)

On the opposite end of the size spectrum we have the Black Myotis (Myotis nigricans), which is one of several equally tiny Costa Rican bats in the genera Myotis and Rhogeesa.  The M. nigricans we encountered just a few days before Christmas weighed just 3.5 grams, about the same weight as a Ruby-throated Hummingbird!

The tiny Black Myotis (Myotis nigricans)

With many outwardly similar-looking genera and species, identification of tropical bats can be a meticulous process.  Distinctions between species are often as subtle as differences in the basal coloration of individual hairs or in the arrangement of teeth.  Since this is the first year we have set up nets after dark, it has been a fun challenge to keep up with the sudden influx of unfamiliar bats that need identifying.

The characteristic "gap" (actually filled by two tiny premolars)
between the molars and canines of species in the genus Myotis

Other notable mentions include the Jamaican Fruit Bat (Artibeus jameicensis), the most commonly encountered bat at Finca Pura Vida; the Common Long-tongued Bat (Glossophaga soricina), which we believe to be at least one of the species that visits the hummingbird feeders at night to sip nectar; and the Pale Spear-nosed Bat (Phyllostomus discolor), the second-largest bat we've captured at the Finca.

The Jamaican Fruit Bat (Artibeus jameicensis)

The handsome (?) face of a Pale Spear-nosed Bat (Phyllostomus discolor)

The nine bat species we have netted so far at Finca Pura Vida are only a fraction of those that occur in the area: the nearby Reserva Natural Absoluta Cabo Blanco -- where one of our bird banding stations is located -- has a list of 41 bat species that have been observed there, and that list continues to grow.  Affiliates of the Cabo Blanco Reserve recently conducted a bat survey, identifying bats both in-hand (using mist nets to capture them) and by recordings of their sonar (which, not unlike bird songs, can be diagnostic of particular species).  During this survey they captured a Silver-tipped Myotis (Myotis albescens) -- a species never before recorded in the reserve -- in addition to twenty other species which were already on the Reserve's official mammal list.

We are thrilled to have the opportunity to become more familiar with the nocturnal fauna of the neotropics, most of which are seldom seen by diurnal animals like Homo sapiens.  The demands placed upon these flying nocturnal creatures have driven the evolution of adaptations that render them utterly bizarre and endlessly fascinating, and the chance to see them up-close is just plain cool.

Following Birds that Follow Ants

Army ants (Eciton burchellii and related species) mean serious business in tropical forests: each day the members of a colony form a large swarm that raids the surrounding forest, stinging to death and dismembering anything small or slow enough to fail to escape.  A passing swarm (which can easily be thirty feet wide and consist of several hundred thousand individuals) creates a panic among the invertebrates of the forest floor, forcing them to come out of hiding and flee.

A swarm is an event of such magnitude that it is clearly audible to human ears.  It consists of the clicks and taps of grasshoppers and crickets attempting to stay ahead of the front, and the ominous hissing of millions of ant legs passing over the leaves of the forest floor.  It is rare that ant-scale events draw the attention of human-sized observers, but when they do, they fascinate us; the mass emergence of periodical (17-year) cicadas and the migrations of monarchs and dragonflies are two prominent examples that regularly make headlines.

As the swarms move through the forest, they remain connected to their stationary above-ground colony by a single column.  The column consists of ants traveling in both directions: those returning from the front of the swarm carrying captured food items, and those leaving the colony having dropped off their booty to return to the swarm.  The video below shows ants traveling along their column.  Ants traveling toward the camera are returning to their colony with food; those traveling away are leaving to rejoin the swarm.

These events attract the attention of certain bird species, which join the front of the swarm to opportunistically capture the invertebrates and other small animals that the ants flush out of hiding. Ant-following birds from the surrounding forest temporarily ignore territorial boundaries and congregate in large numbers to take advantage of the sudden availability of prey.

Northern Barred-Woodcreeper following a trail army ants up a tree trunk

These raids provide unique opportunities to see many birds concentrated at ground-level.  One particularly large army ant swarm occurred nearby the bird banding station at Cabo Blanco late last month, attracting large numbers of Ruddy Woodcreepers, Gray-headed Tanagers, Red-crowned Ant-Tanagers, and Northern Barred-Woodcreepers.  In addition to being an enjoyable spectacle on its own, it was doubly exciting to see that most of the birds present were sporting our aluminum leg bands:

Ruddy Woodcreeper

Gray-headed Tanager

I watched this group of birds for quite a while as the ant swarm moved through the forest.  I decided to fall back when the swarm started down the slope of a steep ravine, and when my tolerance for army ant stings reached its critical threshold.

Are there Fer-de-Lance on the Nicoya Peninsula ?

 Arguably Central America’s most deadly and widespread venomous snake is the Fer-de-Lance or Terciopelo. It can be found in a wide variety of habitats throughout Costa Rica.  Studies have even shown that it can survive -- and indeed thrive -- in disturbed habitats in close proximity to humans.

Fer-de-Lance (Bothrops apser)

The big "question mark" remains on the Nicoya Peninsula.  Although no confirmed records exist for the region, the thing I've learned over the years is that doesn't stop most people from believing they are here.

I actually still hold out hope that they do occur here; there is certainly suitable habitat at the southernmost tip in Cabo Blanco national park, but so far I have never seen one. I do however have an alternate theory of what people are seeing.  

Lyre Snake (Trimorphodon biscutatus)

 Fer-de-Lance (Bothrops apser)

The Lyre Snake (Trimorphodon biscutatus) is a common enough snake throughout the Peninsula in multiple habitats, and could very well be the infamous Nicoya Fer-de-Lances people are seeing. Here are a few reasons why: they have a very similar pattern - it’s not a distinct "X" pattern like the Bothrops, but it does overall have very similar coloration. Their behavior when first encountered is strikingly similar: in Panama I came upon a Fer-de-Lance moving along a bank side.  When it spotted me it quickly coiled up start rattling its tail on the leaf litter and brought its head up. I have witnessed the Lyre Snake do the exact same thing.  Now unlike the Fer-de-Lance it won’t make as tight of a coil or stay like that for long: they usually try the threatening position then scatter. The tail rattling though is the exact same in both, and for me it’s one of the more compelling similarities. If you only get a quick look the lyre snake will also flatten its head in a similar fashion to a pit viper. Their eyes can also fool you at first glance they can create a very narrow slitted iris similar to a pit viper.

The flat triangle shaped head distinct in Pit vippers.

If you were to take a close enough look though you would notice the lack of sensory pit glands that all pit vipers posses.

Sensory pit glands on the front of a Fer-de-Lance

So for now I’m still very skeptical that Fer-de-Lance occur widespread throughout the Peninsula, but I still very much hold out hope they are here and that I can finally confirm their occurrence here.

Big Trees, Kentucky Warblers, and Site Fidelity

La Reserva Natural Absoluta Cabo Blanco -- the Cabo Blanco Absolute Nature Reserve -- was Costa Rica's first national park.  The Reserve celebrated its 50th anniversary last year.  Before the land was preserved, the area was a hodgepodge of private farms and cattle ranches.  Now the 3,000 acres of forest protected at Cabo Blanco are a testament to the impressive speed at which tropical habitats can regenerate: its youth is masked by the presence of gloriously massive trees, including fast-growing giants such as Guanacaste (Enterolobium cyclocarpum) and Ceiba (the genus to which the mighty Kapok belongs).

This forest is the winter home of a number of neotropical migratory songbird species, which is the reason we find ourselves in this wonderful place.  Among them are several species whose numbers are apparently in acutely rapid decline, such as Kentucky Warbler, Worm-eating Warbler, Ovenbird, Wood Thrush, and Swainson's Thrush.  This week we captured all of these species except Ovenbird (although we did manage to capture one at Finca Pura Vida last week).  We also captured and banded two other neotropical migrant warblers: Chestnut-sided and Tennessee.

The most exciting capture of the week was a Kentucky Warbler, not only because of my personal annual sagas trying to spot them in New Jersey, or because they are threatened in the state, but because one of the Kentuckys banded late last year by my team at Cabo Blanco was just recaptured again on Monday, one year and eight days (and about two thousand miles) later.  It was an immature bird at the time of capture, meaning it celebrated its first birthday this past summer, after its first (hopefully successful) breeding season in North America.

Fortunately I keep my photos organized well enough to have located a photo I took of this very bird during last year's research expedition:

Kentucky Warbler when it was originally banded on
December 14, 2013 (© Tyler Christensen)

Same individual as pictured above when it was recaptured
on December 22, 2014 (© Tyler Christensen)

Birds banded in a previous season and re-encountered in a later one are called between-season recaptures, and are not rare occurrences here (at this point about one in ten birds we capture was banded by the team in previous seasons), but we capture Kentuckeys infrequently enough that this was our first between-season recapture of this species.

Recaptures such as this demonstrate winter site fidelity, or the tendency of a bird to return to the same winter territory year after year.  Many of the migrants we capture are site faithful, and recapture rates among our most common migratory species from one year to the next are roughly 18% for Tennessee Warblers, 20% for Prothonotary Warblers, and a whopping 26% for our Northern Waterthrushes!

As several recent studies have shown, winter site fidelity and winter territoriality (which are related) are, in at least certain species, linked to habitat quality - higher-quality habitats often have repeat customers who stake territorial claims within them.

Evidently the forests of the Cabo Blanco nature reserve are agreeable to at least one Kentucky Warbler, who elected to return to spend another winter.  This group of bird banders happens to have made a similar assessment.

Nocturnal Creatures (Part I: Pacific Screech-Owls)

Dusk falls quickly in the tropics, and with it comes a rapid transition between the activities of the diurnal and nocturnal fauna.  As darkness falls, the daytime animals take advantage of the last few minutes of fading light.  The last of the day's hummingbirds fill their stomachs with nectar before calling it a night; the howler monkeys bellow one last claim on their territories; and flocks of Tennessee Warbler settle in to roost, nudging and shouldering each other to vie for the best spot on the branch.  Around this time there is a small window, just before the real darkness sets in, in which the bats and owls leave their daytime roosts and begin their nightly routines.  These are the creatures to whom the night belongs.

© Tyler Christensen

Pacific Screech-Owls (Megascops cooperi, above) are perhaps the most common owls in Costa Rica, much like our Eastern Screech-Owls (Megascops asio) at home in New Jersey.  Both species are flexible in their habitats and diets, making them well-suited to thriving in areas with human habitation.  I photographed the owl pictured above on the grounds here at Finca Pura Vida just a few evenings ago.

For the past few nights we have been capturing owls for our research, applying the same method I used during Washington Crossing Audubon Society's Saw-whet Owl Migration Survey.  This method involves the use of several mist nets and an electronic audiolure that plays the male vocalizations of the owl species being targeted.  Ever curious, owls often come in to investigate and wind up in the nets.

© Tyler Christensen

Various research projects require the capture of owls for study.  Ours involves deciphering patterns by which these birds replace their feathers, and whether these patterns can be used to discern the age of a bird in question.  While this research may not be universally interesting (I can think of several people off the bat who were visibly regretful after asking for more detail), I do think we can all appreciate the spectacular encounters that happen to go along with it.

You cannot catch owls here without also catching bats, and catch them we did -- indeed, some were as large as the owls themselves.  Our encounters with these bats will be the topic of Part II of this post.

Herpetofauna of the Nicoya Peninsula

Our primary objective while were here in Costa Rica is focused on ornithology research, but that doesn't mean we don’t delve into other subjects.  Much is still unknown about the distribution and abundance of reptiles and amphibians here on the Nicoya Peninsula .  Over the past few years we have taken a lot of notes and data points on where we have found various species of snakes, lizards, frogs, and turtles across the Peninsula.   

As we've been going along, I've been using the Meet Your Neighbors photo studio technique to isolate subjects on completely neutral backgrounds. It serves a dual purpose of having very clear record shots, and also will hopefully go into a guide of sorts for the herpetofauna for the Peninsula at some point. 

Our first day came with an interesting discovery -- On our way from the ferry to the Finca, Tyler spotted something sliding back and forth across the road: a Green Ratsnake  (Senticolis triaspis). This Colubrid is in the same family as our Black Ratsnake at home, and they share very similar behavior and diet. 

Green Ratsnake  (Senticolis triaspis)

 

 

Later on in the first night as we were walking around the Finca, Tyler spotted something on the side of one of the buildings. It was a large frog, apparently scanning the property from a high perch. We quickly grabbed a butterfly net and lowered him down for identification.  It turned out to be the ever-interesting Common Milk Frog (Trachycephalus venulosus). These frogs can secrete a noxious mucus-like chemical from their skin when disturbed.   

Common Milk Frog (Trachycephalus venulosus)

 

The latest species we encountered was Costa Rica's poster-child of fauna, the Red-eyed Tree Frog (Agalychnis callidryas).  We had heard them in the past at the Finca, but could never locate them. The other night, we set out on a mission to finally locate them and get photographic documentation. After what some might call an intrepid adventure, we located between 6-7 individuals.  As you can see, it was well worth it -- "charismatic" doesn't even begin to describe these frogs. Interestingly enough, they are very variable in coloration, depending on if you’re on the Pacific or Caribbean side of Costa Rica.  The frogs from the Caribbean side are more colorful, but the Pacific variant has their own unique charm. 

Red-eyed Tree Frog (Agalychnis callidryas)

Warm Greetings

A trio of Mangrove Swallows (tropical relatives of our Tree Swallow) was swirling behind the ferry that crosses the Gulf of Nicoya, showing off the impressive aerobatic skills shared by all members of the swallow family.  Brown Pelicans travelled low in formation over the water.  Magnificent Frigatebirds, fork-tailed and long-winged wanderers of the open ocean, circled higher, watching and waiting to steal the hard-fought-for meal of a Laughing Gull or Royal Tern.  The occasional Brown Booby would cross in front of the ship.

Brown Pelicans aboard a small fishing boat in the Gulf of Nicoya

Our arrival in Costa Rica yesterday marks the beginning of the fourth annual research expedition of the Nicoya Peninsula Avian Research Station.  In each of these four years my research partner Sean Graesser and I have traveled to the Nicoya Peninsula of the northwestern portion of the country to collect important data on some of the more vulnerable species of neotropical migratory songbirds, which spend their winters here.  Over the next seven weeks we will run several bird banding stations to capture, mark, and study these long-distance migrants, and to collect data from individuals that we banded in the past that have returned.

The sun was going down as we turned down the dirt road that leads to Finca Pura Vida, the farm on which we will live for the next two months.  As we tried (in vain) to dodge the myriad potholes, two bird calls familiar to us northerners came through the open windows: the "stchip" of a Yellow Warbler and the “kinkachurr” of a Summer Tanager.  I welcomed these as warm greetings to our return to Costa Rica.  It’s good to be back!

Season Highlights

Although it certainly doesn't feel like it, a full month has gone by since the NPARS team returned to North America from its latest excursion to the American tropics.  For seven weeks, our team of volunteer researchers lived and worked on the Nicoya Peninsula of northwestern Costa Rica collecting important data on neotropical birds.  To officially close the research season, I'd like to look back at some of the highlights of the trip, including some of my favorite photos of and encounters with birds and other wildlife.

American Crocodile (Crocodylus acutus) near our banding site at Refugio Curu

Scarlet Macaw

This Crab-eating Raccoon (Procycon cancrivorus) paid the
banding station at Refugio Curu a visit just after Christmas

Occasionally we would have slow days at the banding station, which would give us opportunities to divert our attention to things other than birds.  No matter how much time we devote to looking, the tropical forests of Central America never fail to offer something exciting and new - especially when we turn our attention to the small and easily-overlooked.

Nogodinid Planthopper Nymph

Occasionally we encountered the remarkable-looking planthoppers of the family Nogodinidae.  Nymphs of these planthoppers grow long, waxy filaments that resemble optical fiber from the tips of their abdomens.  This feature has earned such nymphs the informal nickname "fluffy bums".  The exact function of these wax-like filaments remains unknown, although they may provide a defense somewhat like the detachable tails of lizards and geckos; an attacking predator may end up with a mouthful of wax rather than the insect itself.  If disturbed, these planthoppers will catapult themselves into the air with an audible 'POP'.

Dead Leaf Katydid (Mimetica sp.)

Bark Mantis (Liturgusa sp.)

Caterpillar 'feet' (Automeris sp.)

A lot of people have been asking me how we get the shots with white backgrounds; the method used involves photographing subjects on a sheet of translucent white plastic, which is illuminated from above and below using remote-controlled flashes.  The goal is to have an evenly-lit subject on a perfectly white background, free of shadows.  I'm an amateur when it comes to this mode of photography, and experienced photographers can have much more elaborate (and innovative) studios.  Twan Leenders, president of the Roger Tory Peterson Institute, constructed a field studio from the back of his rental car while he was visiting the banding stations, and used it to photograph banded birds prior to their release.

Twan Leenders photographing birds in a field studio

Prothonotary Warbler - Photograph © Twan Leenders; used with permission

The team completed its third unofficial Christmas Bird Count on January 11th.  Since there is no official Audubon Count Circle in this region of Costa Rica, we decided to make this year's bird count purely a numbers game with the object of seeing as many species as possible.  This sort of birding has little scientific value, but it's a great way for the team to take a break from research, practice their identification skills, and have a great deal of fun.  After a session of serious strategizing at the Finca the night before, we had laid out an agenda for the following day to cover as many habitats as possible and maximize our species potential.

Chestnut-sided Warbler

Snowy Egret at the ferry in Paquera

We birded for nearly twelve hours, and had visited sites along the entire eastern coast of the Peninsula.  By the end of the day we had a total of 128 species, just seven species behind last year's high count of 135.  Just like last year, the final species of the day was a Pacific Screech-Owl singing in the yard at Finca Pura Vida just after dark.

Pacific Screech Owl, # 128 on our Christmas Bird Count

Most reptiles and amphibians are active at night, making this the best time to find them.  We spent several late nights cruising the roads after dark, which is a good way to cover a lot of ground and spot critters more easily against the asphalt.

On a particularly slow evening, when we were about to turn the car around and call it a night, "WHAP!" - something large, about the size of a baseball, fell 40 feet from the trees above the road and landed on the car.  When we stopped to look, attached to the passenger-side mirror was Costa Rica's largest tree frog, the Veined Tree Frog (Trachycephalus venulosos).  This species can, when disturbed, secrete copious amounts of a sticky, irritating milky liquid (hence its Spanish common name Rana Lechera, or Milk Frog).  Incredibly, the frog remained healthy and intact after its encounter with our car.

Veined Tree Frog (Trachycephalus venulosus)

During a two-day visit to the Karen Mogensen Reserve in the mountains of the Nicoya Peninsula, we found, among other things, a gorgeous Tropical Kingsnake (Lampropeltus triangulum); these snakes are spectacular mimics of the venomous Coral Snake (genus Micrurus).  Although kingsnakes are completely harmless, their strong resemblance to the "real thing" causes most would-be predators to opt out.  Even though we have both Kings and Corals here on the Nicoya Peninsula, this was our first encounter with L. triangulum since we began the project.

Tropical Kingsnake (Lampropeltus triangulum), a convincing Coral Snake mimic

The author with a Coral Snake in 2012; photograph © Jared Flesher

Hummingbirds aren't the only creatures that enjoy our nectar feeders at Finca Pura Vida; after dark, nectar-feeding bats come in droves to sip sugar water.  One night when we had the mist-nets open at the feeders to capture and photograph bats, we had an incidental capture of an insectivorous (insect-eating) species we'd never seen before, the Black-winged Little Yellow Bat (Rhogeessa tumida).  "Little" seems to be an understatement, as this bat was minuscule, about the size of a hummingbird.

Black-winged Little Yellow Bat (Rhogeessa tumida)

We also found that it was carrying a tiny hitchhiker called a Flat Fly, a type of parasitic fly that we find often on birds in North America.  As their name suggests, Flat Flies (Family Hippoboscidae) are dorsally compressed, allowing them to navigate the spaces between feathers or fur with unsettling speed, thereby avoiding the beaks, claws, or teeth of their hosts while they groom themselves.  Most species are host-specific, meaning they may only be found on one, or at most few, host species.

Flat Fly (Hippoboscidae) found on the
tail membrane of Rhogeessa tumida

Even after some editing, I have nearly 10,000 photos from the trip.  For my parting shot, I discreetly took this photo of NPARS's co-director Sean Graesser and banding technician Benny Jacobs-Schwartz photographing birds near Monteverde.  It's hard to convey these seven weeks of experience in one blog post, and harder still to articulate just how special this area of the world is; but if I had to try using a single photo, it would be this one: