Final Banding Days

Six weeks can go by so quickly!  It seems as though only a few days ago we were opening our first nets here on the Nicoya Peninsula.  But, whether we like it or not, our final days of banding in Costa Rica have come to an end.  Later we'll be posting highlights, photos, and banding totals from the entire six-week project, but in this post we're only covering our final banding sessions at our sites in Refugio de Vida Silvestre Curu and in Reserva Nacional Cabo Blanco.

Banding a second-year Yellow Warbler

Our last banding session at Cabo Blanco resulted in 10 new birds and 11 recaptures of previously-banded birds, representing a total of 11 species.  Among these birds was a second-year Worm-eating Warbler, only the third ever banded by our team, and the second one at Cabo Blanco.  

New
2	Ovenbird
2	Tennessee Warblers
1	Red-crowned Ant-Tanager
1	Northern Barred-Woodcreeper
1	Ruddy Woodcreeper
1	Rufous-and-white Wren
1	Plain Xenops
1	Worm-eating Warbler
Recaptures
4	Gray-headed Tanager
3	Ruddy Woodcreeper
1	Ovenbird
1	Rufous-and-white Wren
1	Bright-rumped Attila
1	Long-tailed Manakin

Nicole Guido with the last migrant captured at Cabo Blanco; a second-year Ovenbird

Totals at Curu were much higher, and our last banding session yielded some particularly cool birds.
Among the newly-banded birds were 30 each of both residents and neotropical-migrants, and 14 and 17 recaptured residents and neotropical migrants, respectively; altogether the total captures consisted of 91 individuals representing 32 species.

New
9	Tennessee Warbler
5	Long-tailed Manakin
4	Black-headed Trogon
4	Northern Waterthrush
4	Philadelphia Vireo
3	Prothonotary Warbler
2	Yellow-bellied Flycatcher
2	Rose-throated Becard
2	Clay-colored Robin
2	Rose-throated Becard
2	Streak-headed Woodcreeper
2	Slate-headed Tody-Flycatcher
2	Wood Thrush
1	Blue-black Grosbeak
1	Green Kingfisher
1	Great Kiskadee
1	American Pygmy-Kingfisher
1	Gray-headed Tanager
1	Yellow-throated Euphonia
1	Greenish Elaenia
1	Northern Scrub-Flycatcher
1	Bright-rumped Attila
1	Olivaceous Woodcreeper
1	Gray-headed Dove
1	Great-crested Flycatcher
1	Summer Tanager
1	Kentucky Warbler
1	Painted Bunting
1	American Redstart
1	Yellow Warbler
Recaptures
6	Northern Waterthrush
6	Prothonotary Warbler
5	Long-tailed Manakin
3	Tennessee Warbler
3	Rufous-and-white Wren
2	Barred Antshrike
2	Clay-colored Robin
1	Greenish Elaenia
1	American Pygmy-Kingfisher
1	Wood Thrush
1	Dusky-capped Flycatcher

The most commonly-encountered bird this session was Tennessee Warbler, which showed a big increase in the number of birds captured compared to the other two banding sessions at the site.  On more than one occasion we would find several in a single net, presumably having been foraging together, which Tennessees usually do on their wintering grounds.  Indeed, large flocks of Tennessees (up to 60 or 70 individuals) are not an uncommon sight.  For a bird that is only seldom observed in our region of North America (let alone captured and seen up-close), their abundance here in Costa Rica gives us a rare opportunity to learn to differentiate the sexes of first- and second-year birds.  There is so much overlap in the appearance of of young males and females that, even with experience, the genders of many birds remain unidentified.

Second-year female (left) and second-year male (right)
Tennessee Warblers (sexes confirmed by wing length)

Other notable captures from our final sessions included a recaptured Wood Thrush originally banded at Curu on December 19, 2012, an adult male Painted Bunting, two Yellow-bellied Flycatchers, and the season's only Yellow-throated Euphonia.

The stunning plumage of a male Painted Bunting

A male Yellow-throated Euphonia

A male Kentucky Warbler

I either forget this detail or it gets worse each year, but the last banding day of the trip was a very sad one, full of nostalgia for another productive and exciting six weeks of research in Costa Rica.  After our final net check at noon, we processed the last birds (three Tennessee Warblers and a flycatcher called a Great Kiskdadee) and removed all our equipment from the station and surrounding forest and loaded it into the car.  It's interesting to see an entire banding station (a table, two crates of bird banding equipment, six chairs, twenty-two nets, forty-four net poles, and four volunteer bird banders) get packed into a small SUV.  The contents of the car were returned to our headquarters at Finca Pura Vida, the equipment to be stored until next year, and the banders to pack for their return home.

The last bird of the season: a Great Kiskadee

Pajaro Campana

After one of our last banding days at Cabo Blanco, our group stopped in Montezuma to buy groceries before returning to the Finca.  Two sounds drifted over the noise of cars, shouting, talking, and waves crashing against the adjacent Playa Montezuma.  First a loud, metallic BONK! followed by a piercing high-pitched squeak, both which of could be produced by a rusty gate being forced open; we knew this to be the sound of the enigmatic and renowned Three-wattled Bellbird, and it was singing from just up the hill from where we stood.

We ran up the road, pausing periodically for the bird to sing so we could locate its position.  The bird appeared to be singing from the treetops within the grounds of a hotel called the Luna Llena Lodge.  We followed a network of concrete pathways onto the hotel property, situated on a steep hillside overlooking the Pacific.  Finding a window through the vegetation that offered a view of the bird was very challenging; we spread out among the network of pathways, intruding on more than a couple of private cabins.  Eventually we found a spot where we could see, at the top of an Ylang-Ylang tree, a brown-and-white bird about the size of a pigeon.

Two of us had our cameras, but not our telephoto lenses, and so ran back down the switchback paths, down the road, jumped into the car, started it, stalled it, cursed ourselves for not choosing a car with an automatic transmission, started it again, raced to the house, jumped the gate, grabbed the lenses, jumped back into the car, stalled it, cursed, started it again, and sped back to Montezuma, all in under 15 minutes (which, believe us, is very good time).

A singing male Three-wattled Bellbird

Three-wattled Bellbirds have one of the most complex seasonal migration patterns of Costa Rican birds.  As birds that eat almost exclusively fruit, their migration is dictated by regional and seasonal patterns of fruit ripening.  One study conducted in Costa Rica which contributed greatly to the knowledge of their seasonal movements involved capturing Bellbirds during the breeding season, radio-tagging them, and periodically relocating each individual via aircraft.  They found that by October the Bellbirds that bred near Monteverde had migrated to the Carribean lowlands, then to the Pacific lowlands by November, and were back in the Monteverde region by March to initiate the breeding season.  One of the birds that was banded near Monteverde during the wet season was relocated during the dry season at Reserva Cabo Blanco, where we operate one of our bird banding stations!

Their complex and widespread migration pattern poses challenges to the conservation of the Three-wattled Bellbird; not only must their breeding habitat be protected, but also the habitats in which they migrate and spend the non-breeding season.  Several worthy initiatives, including the Corredor Biologico del Pajaro Campana, are attempting to surmount these challenges, and are attempting to preserve biological corridors between the breeding and non-breeding regions.

 We are very fortunate to work in an area that has a high number of Bellbirds during the non-breeding season; it seems that they arrive on the Nicoya Peninsula shortly after we do, giving us the opportunity to see them each year.  One time we even saw one in our yard at Finca Pura Vida, feeding on fruits of an Ylang-Ylang (which seems to be a popular tree among Bellbirds; we have since planted more).  They arrived later this year than last, but early enough where we managed to observe one before our time in Costa Rica came to an end.

Dairo Vinasco with his photos of the Three-wattled Bellbird

Monkeys Meet a Boa Constrictor

Here in northwest Costa Rica we have two species of monkeys; Mantled Howler Monkeys (Alouatta paliatta), which consistently wake us up at 5:15 each morning with their monstrous bellowing, and the White-faced Capuchin (Cebus capucinus), which is the more common of the two.  Where we live at Finca Pura Vida there is a troop of the latter, numbering about a dozen individuals, that comes by regularly to scour the yard in search of food.

Capuchins are the most well-studied of the New World primates; they are adaptable, absurdly intelligent, and have complex social hierarchies.  They travel in groups of up to several dozen individuals, methodically moving through forests, gardens, and backyards in search of ripe fruits, bird nests, small mammals, and insects.  When faced with a challenging prey item, Capuchins will hunt cooperatively; several times now I have watched the entire troop here at the Finca converge on a single Variegated Squirrel (a close relative of our familiar Eastern Gray Squirrel) to capture, kill, and share it - sort of a ghastly scene, not for the faint of heart.

Another scenario in which the entire troop behaves cooperatively is when they cross paths with a potential predator.  Several weeks ago we encountered a Boa constrictor, about 4' in length, crossing the dirt road near the Finca.  We bagged it and brought it back to the house for some photos, and it just so happened that the monkeys were in the yard (robbing the bananas from the bird feeder, as they do regularly, much to our continual frustration) when we extracted the Boa from the bag.  Instantly it was spotted by one of the young females of the group, who began sounding the alarm (sort of an outraged- and offended-sounding "UGH!").  Within seconds the entire troop had congregated on the roof nearby to inspect the danger, and to issue alarm calls of their own.

Interestingly, younger Capuchins will sound alarm calls much more frequently, and often inappropriately - they may scold harmless snakes, snake sheddings, and non-predatory birds, for example.  But they learn to discriminate between the harmless and the potentially threatening creatures as they get older and gain more experience.  An interesting hypothesis regarding snake-mobbing is that when older, more experienced adults sound the alarm to alert the group of a snake of the dangerous variety, they are helping teach the younger, inexperienced monkeys to differentiate between them and the harmless variety.

Adult male with a younger female reacting to a Boa constrictor

After about twenty minutes, the monkeys seemed convinced that the snake's presence was sufficiently announced, and dispersed to continue their routine vandalizing of the yard in search of food.  We photographed our boa and released him, well out of sight of the monkeys.

The Mangrove Hummingbird

The Mangrove Hummingbird (Amazilia boucardi) is one of just three species of birds endemic to Costa Rica; it inhabits coastal mangrove habitats from the Peninsula de Nicoya to the Peninsula de Osa, and only where its favorite species of mangrove, the Tea Mangrove (Pelliciera rhizophorae) grow.  The hummingbird is endangered, with an estimated 1,500 - 7,000 individuals remaining, and a population that appears to be continually declining as their habitats become scarcer.

Last year, we heard through the grapevine that a single individual, a female, was making regular appearances at a feeder at a bar in a town not far from Finca Pura Vida.  The bar is adjacent to a small mangrove estuary where the Rio Panica meets the Pacific Ocean.  We visited the bar, ordered drinks, waited, and within twenty minutes, we had living proof that Mangrove Hummingbirds are in the area.

Our very first Mangrove Hummingbird visiting the feeder at a local bar

Further searching, however, failed to produce additional sightings of these endangered hummers. Just the single female visiting the single feeder at the bar.  Last week, however, we had a breakthrough; while travelling elsewhere on the peninsula, we located a stand of almost exclusively Tea Mangrove.  This stand showed a lot of promise, so we returned the following day to explore.

The buttressed roots of Pelliciera rhizophorae

Sean Graesser and Nicole Guido searching for Mangrove Hummingbirds

Mangrove mud is not easy to walk through; it's like walking through knee-deep pudding that smells of particularly smelly hard-boiled eggs.  Some of the ground is more or less solid, but every few steps one encounters an unpredictable sinkhole that wants to steal your shoes.  Once you get past the mud, though, walking through mangroves is a great deal of fun; we quickly found ourselves surrounded by Prothonotary Warblers, Mangrove Vireos, and Northern Waterthrushes, which were seemingly oblivious to our presence, and were willing to come within a few feet of our cameras.

Northern Waterthrush

Not ten minutes after entering this mangrove forest, we spotted a hummingbird perched on a mangrove twig; the combination of the white belly, dark tail, bluish throat, and red underbill were more than enough to identify it as a Mangrove Hummingbird.  It remained perched for a few moments before flying into the canopy to dip its bill into the Tea Mangrove flowers above us.  Within a few minutes we had spotted several more zipping through the mangroves, pausing only briefly to sip from flowers or glean spiders from their webs.  How exciting it was to finally observe them in a natural setting!

Mangrove Hummingbird feeding from a Tea Mangrove flower

We watched several individuals make their rounds visiting the available Tea Mangrove flowers, interrupting their routine only to chase away intruding Rufous-tailed or Steely-vented Hummingbirds, or to be chased themselves by the much larger Scaly-breasted Hummingbirds.  Obviously these tiny birds lack the capacity to acknowledge just how special they are, so we spent some time acknowledging it on their behalf; we remained up to our knees in the mangrove swamp for nearly an hour while we admired them; the tiny, tough, and increasingly rare Mangrove Hummingbird, found nowhere but among its favorite trees in the mangrove swamps of Costa Rica.

Birding the Cloud Forest

Just outside the gates of the Monteverde Cloud Forest Reserve is the Hummingbird Cafe.  When visiting the Monteverde area, this cafe is a must-see.  They maintain an array of about 10 hummingbird feeders that hang from the trees and roof overhangs outside the building.  The abundance of hummingbirds at this spot is astonishing, as is their diversity - more than 25 species have been observed visiting these feeders.  And so single-minded are they in their quest for nectar that they have become seemingly oblivious to human presence, and will even land on your hands if doing so facilitated their feeding.

Nicole Guido provides a Purple-throated Mountain Gem with a perch

Sean and Dairo photographing hummingbirds

In the late morning we hiked into the Cloud Forest Reserve to the elfin forests of the continental divide; here, high winds and steep slopes have sculpted a miniature forest of tiny, gnarled trees that crown just above our heads.  The trail follows the ridge along the Continental Divide, which separates the Carribean and Pacific slopes of Costa Rica.  The wind drags heavy, moisture-laden clouds up the slopes of the Carribean slope, showering the forests at the mountaintops with mist.  Certain birds, including highland endemics like Slaty Flowerpiercer, Blue-and-Gold Tanager, and Spangle-cheeked Tanager, are abundant in these miniature forests.

Slaty Flowerpiercers use their uniquely-shaped bills to make

holes in flowers from which to "rob" nectar

Spangle-cheeked Tanager

A female Purple-throated Mountain Gem incubating eggs 

and enduring the high winds of the Continental Divide

Without doubt the most iconic bird found at Monteverde is the Resplendent Quetzal.  These birds are the largest, and arguably the most beautiful, members of the Trogon family, and are endemic to the highlands and cloud forests from southern Mexico to Panama.  The Quetzal's beauty (shimmering iridescent green, crimson breast, and long flowing tail) and its secretive demeanor make it one of the most charismatic of the cloud forest avifauna.  The Quetzal is at the top of the "most wanted" list for most of the thousands of birders who flock to Monteverde each year to enjoy its rich community of highland bird species.

Male Resplendent Quetzal

We birded for nearly ten hours on our first day to Monteverde, and added about three times as many new bird species to our trip list.  These four happy birders returned to the hotel in the town of Santa Elena to upload photos, recuperate, and prepare for the following day of watching birds.

Monteverde

As warm, moisture-laden air from the Carribean is pushed up the mountain ranges of the continental divide, the decrease in air pressure and temperature causes the water in the air to condense, soaking the high mountaintop forests with nearly constant mist and precipitation.  Every available surface in these forests - tree trunks, limbs, logs, and even leaves - has been colonized by ferns, mosses, lichens, liverworts, orchids, and bromeliads, which collect water from the mist and shower the forest below.  The most famous of the Central American cloud forests is Monteverde.

The forests surrounding Monteverde are a world-renowned birding hotspot; dozens of highland bird species, endemic to the cloud forest, can be found in the parks and preserves of Monteverde.  On Saturday, the NPARS team left the Nicoya Peninsula for its annual side-trip to the birding mecca of Monteverde.

Visit to Estero Coyote

On the southern coast of the Nicoya Peninsula, where the Rio Bongo meets the Pacific ocean, is an estuary containing expansive coastal mangrove habitat.  Habitats such as these are home to a number of bird species found nowhere else but among mangroves, and many have received such apt names as Mangrove Black-Hawk and Mangrove Vireo.

A dense stand of Red Mangroves

We had barely penetrated the mangroves when we spotted our first mangrove endemic, the Mangrove Cuckoo.

Mangrove Cuckoo

Mangrove Black Hawk

On our way back from Playa Coyote and the estuary, we passed many hundreds of acres of grazed cattle pastures.  Their artificial presence notwithstanding, they can be good places to find grassland species like the Double-striped Thick-Knee, as well as wintering migrants like Eastern Meadowlarks and American Kestrels.

The bizarre-looking Double-striped Thick-knee; mostly nocturnal, these birds of dry grasslands use their relatively large eyes to hunt insects and small vertebrates at night.

Next week, after finishing our banding session at Reserva Nacional Cabo Blanco, the NPARS team is heading inland for a few days of birding in the cloud forests of Costa Rica.  We'll be writing the next few posts from Monteverde, a world-renowned birding destination, distinguished by birders for its assortment of rare endemic highland species.  Stay tuned!