In early November we departed Hilton Pond Center for two weeks in Costa Rica, where since 2004 we've been conducting the only long-term systematic studies of Ruby-throated Hummingbirds (RTHU) on their Neotropical wintering grounds. Until this year, our Operation RubyThroat expeditions had been to Guanacaste Province on the country's Pacific Coast, where RTHU from North America concentrate in expansive Aloe Vera plantations and partake of non-native aloe's copious nectar (above). That area around Liberia and Cañas Dulces--discovered almost ten years ago by our tico guide and colleague Ernesto Carman Jr.--has been quite productive (762 ruby-throats banded at several different study sites) and we have yet another citizen science trip to Liberia coming up in February. (Limited space is still available; see Costa Rica East 2012.)

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A year or so ago, 'Nesto documented another winter population of RTHU in commercial fields of Chayote, a squash grown on horizontal trellises (above) in the river valley at Ujarrás on Costa Rica's Caribbean slope. These birds were gathering in part of the country where RTHU historically have been reported only a few times each year. 'Nesto noticed RTHU numbers at Ujarrás didn't seem nearly as high as over in Guanacaste, but still we couldn't resist the opportunity to mount an expedition to band and observe Ruby-throated Hummingbirds where "they're not supposed to be."

Our citizen scientists ("The Cayoteers") did a great job helping us capture a total of 44 RTHU--the first ever banded in the greater Orosi Valley--but an added benefit of running mist nets and being there to make observations is that we caught 12 other varieties of hummers and sighted a total of 22 trochilid species--nearly half the 50 or so hummingbirds known to occur in all of Costa Rica! It's beginning to look like Ujarrás may be Costa Rica's "hummingbird capital"--at least during months when wild plants aren't blooming and Chayote is the predominant (and most readily available) source of energy-rich nectar. With that in mind we'll certainly be taking another citizen science group to Ujarrás late next fall--sign-ups will be announced soon for the 10-18 November 2012 trip--but for now we'd like to tempt folks with a photo essay that includes images of every hummer species we captured this year. We hope you enjoy the following portfolio of 13 colorful Costa Rican hummingbirds "in-the-hand" and will sign up to join one of our future expeditions.

All text & photos © Hilton Pond Center

All text & photos © Hilton Pond Center

Although we did find Ruby-throated Hummingbirds in the Chayote fields at Ujarrás--and observed far more than the 44 we banded--the most common hummer species by far was Rufous-tailed Hummingbird, Amazilia tzacatl (above). These aggressive, nearly ubiquitous, medium-sized (4") hummingbirds were constantly hitting our mist nets, so beginning Day One after we held a rufous-taled for examination by the group we instructed everyone to carefully dump them out of the nets and wait for something else.

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Rufous-tailed Hummingbirds are accurately named, with bright rusty rectrices (above) they fan and flash at conspecifics when defending territories. They have stout wings and what our volunteers considered to be cantankerous dispositions; seldom did a rufous-tail sit quietly in a mist net after capture.

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Rufous-tailed Hummingbirds are sexually monomorphic, with males and females looking alike externally. Both sexes have iridescent green heads and bodies and slightly decurved bills with some degree of red. With a range that stretches from Central Mexico through northern South America--and with an apparently ability to co-exist with human development--this species is probably one of the more common of the world's hummingbirds.

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Only slightly less frequently mist netted than rufous-tails were Steely-vented Hummingbirds, Amazilia saucerrottei, which take their common name from the gun-metal color of their undertail coverts (above). The tail itself is even brighter blue.

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Head-on (above)--with its iridescent green head and gorget--the Steely-vented Hummingbird superficially resembles its congeneric Rufous-tailed Hummingbird, but the former has a straight, black, somewhat short bill while that of the rufous-tailed is decurved and reddish.

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Steely-vented Hummingbirds are quite distinctive in lateral or dorsal view, with a somewhat chunky four-inch body and a rump of rainbow hues (above). Like the rufous-tail, this species is sexually monomorphic. It ranges from Nicaragua to Venezuela, although the South American population may actually be a separate species--the Blue-vented Hummingbird, A. hoffmanni.

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By far the largest hummer we caught at Ujarrás was the six-inch-long Violet Sabrewing, Campylopterus hemileucurus, whose massive wings had stout feathers with amazingly wide waxy-looking shafts (above).

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A male Violet Sabrewing (above) has hints of green in his back but the predominant color is a striking metallic purple. White tail-tips contrast starkly with darker hues as a male approaches. You can also tell he's getting close by the clacking of his wings. This is one BIG hummingbird!

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Like their male counterparts, female Violet Sabrewings have long, black, decurved bills (male above), but otherwise they are sexually dimorphic. The female's plumage is far plainer: Green back and head with a white breast and tail tips, and only a hint of purple on the throat. We caught no female sabrewings in the Chayote fields, although they likely were there. The species is primarily Central American occurring from southern Mexico to western Panama.

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The next-biggest hummingbird among the Chayote was the five-inch Green-breasted Mango, Anthracothorax prevostii, among which adult males (above) are metallic green with a central black stripe bordered by blue. (CAVEAT: Although most authorities state this species is sexually dimorphic, there is some indication adult females occasionally resemble males, probably with less black on the keel and throat.)

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The more typical female Green-breasted Mango (above) has a green back, but the breast is white with a long vertical keel stripe of green and black.

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Both sexes of Green-breasted Mangos have reddish tails, but in adult males (above) the color is much more metallic and intense. Tips of outer tail feathers in females are white. Recently fledged male and female Green-breasted Mangos look alike and resemble their mothers, except they have broad streaks of chestnut (right) to either side of the dark central streak. The immature individual in the photo at right is likely a female; in young males the dark streak typically extends to the base of the lower mandible. Green-breasted Mangos breed from Mexico to Costa Rica; in 2005 we even mist netted some on San Andrés Island in the Caribbean Sea about 140 miles east of Nicaragua. The species is believed to be partly migratory within Mexico and wanders into the U.S.; a few are believed to be year-round residents in the Rio Grande River Valley.

All text & photos © Hilton Pond Center

All text & photos © Hilton Pond Center

The one other species we netted in the "largish hummingbird category" (four inches or more) was the Brown Violetear, Colibri delphinae, We nicknamed this one the "stealth hummer" because it's overall appearance was military, with a dull brown back (above) and gray-brown belly (below).

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Brown Violetears may be drab in dorsal or ventral view, but head-on they show bright metallic colors (below): A bright bluish cheek that gives the species it common name, plus an iridescent gorget that includes several shades of blue and green.

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Brown Violetears are sexually monomorphic and are relatively uncommon, so we were pleased to get to handle two individuals. This is a species that hangs out primarily in forest canopies from Central America into northern South America; it's interesting that disjunct populations occur as far away as Trinidad and Brazil.

All text & photos © Hilton Pond Center

From the bigger hummers we move to the smallest on our Ujarrás study site: Scintillant Hummingbird, Selasphorus scintilla, a congener of the Rufous Hummingbird, S. rufus, that breeds in western Canada and the northwestern U.S. and occasionally shows up in winter across North America. The adult male Scintillant in the photo above had an amazingly brilliant and wide gorget that flared out on the posterior corners.

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Scintillant Hummingbirds are endemic only to Costa Rica and western Panama. Weighing just two grams as adult males (above), the species is only slightly larger than the world's smallest hummer, the Bee Hummingbird, Mellisuga helenae, of Cuba. (By comparison, adult male Ruby-throated Hummingbirds typically weigh about 2.5 to 3 grams.)

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Adult Scintillant Hummingbirds are sexually dimorphic, but immature males resemble females with rusty tails tipped in white. Thus, based on a dorsal view we can't be completely sure of the sex of the bird just above.

All text & photos © Hilton Pond Center

However, a view of that bird's non-metallic gorget (above) shows flaring like that in the image of the adult male, so we're guessing it's an immature male.

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Had we thought to look at the wing feathers of that supposed immature male Scintillant, we might have been able to confirm its sex. It's our understanding the lead (#10) primary feather (above) of the adult male Scintillant Hummingbird is curved and sharply tapered, which gives the bird a distinctive wing trill during courtship. That said, we don't know for sure whether immature males have this wing shape.

All text & photos © Hilton Pond Center
Male Scintillant Hummingbird photo courtesy Ela Mayorga Villanueva

Adult male Scintillant Hummingbirds are spectacular in flight, zipping among flowers such as the above-pictured Blue Vervain, Stachytarpheta frantzii, flashing their gorgets at competitors and nearby females.

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The intended result of all that gorget-flashing is the male Scintillant Hummingbird will copulate with a a female that will lay an egg or two in a tiny lichen-covered nest like the one above, found in a Coffee shrub a few feet off the ground by Ernesto Carman Jr. and Ela Mayorga Villanueva.

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Another small hummer we encountered in our nets was the Stripe-throated Hermit, Phaethornis striigulari (above), which more than made up for its diminutive body size with its lengthy tail and long, decurved bill. To say this bird stretches four inches is rather misleading, as shown when you compare its body to the size of the bander's thumb. The species breed from southern Mexico into northwestern South America.

All text & photos © Hilton Pond Center

The Stripe-throated Hermit's inch-and-a-half bill is yellow at the base of the lower mandible and decurved, the latter characteristic allowing it to probe long tubular flowers such as those of the Acanthaceae.

All text & photos © Hilton Pond Center

Stripe-throated Hermit's tail is also quite long--especially its central rectrices (above). This is a common but not universal characteristic among hummingbirds in the Hermit Subfamily (Phaethornithinae), all of which are sexually monomorphic. Incidentally, Sicklebills--with their sharply decurved mandibles--are also hermits.

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We've been trying to capture a Stripe-throated Hermit ever since we started research in Costa Rica, but over in Guanacaste they never entered the aloe fields and stayed instead in the herbaceous level of the forest were our mist nets were not. Little did we know when we finally caught one we would learn the species has unpigmented skin in its feet (above), allowing a clear view of blood vessels in the tiny hummingbird's even tinier toes. Just amazing!

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Another small hummingbird we expected and were pleased to find among the Chayote was the Garden Emerald, Chlorostilbon assimili, a species endemic to Panama and Costa Rica's Central Valley and southern provinces. Females (above) and immature males have gemstone-green backs, clear throats and bellies, and a long white post-ocular stripe that sets off the dark eye. A very important field mark in this species is the bill; it's completely black above and below.

All text & photos © Hilton Pond Center

Young males and female Garden Emeralds also have greenish flanks and tri-colored tails (above), the latter with a broad blue-green band and tips of white.

All text & photos © Hilton Pond Center

As the immature male Garden Emerald matures he molts all his feathers, replacing everything white with that sparkling emerald color that gives the species its common name. Even the yellow-tinged plumage on the back of the youngster above will become darker green.

All text & photos © Hilton Pond Center

In dim light (above), a male Garden Emerald sporting adult plumage looks almost dark. However, one can still make out the species' slightly forked tail and completely black bill.

All text & photos © Hilton Pond Center

So here's an image of another smallish hummer with brilliant emerald-green plumage, but it's NOT a Garden Emerald. You'll recollect THAT species had a jet-black bill, and the bird in the photo above has a lower mandible that's mostly reddish-orange. What we have here is a congener in Canivet's Emerald, Chlorostilbon canivetii, which we're familiar with from our time in Guanacaste on Costa Rica's Pacific Coast.

If you have an older field guide you'll find no mention of Garden Emerald or Canivet's Emerald because they were split in recent years from Fork-tailed Emerald; the two new species look different (at least with regard to bill color) and supposedly are geographically separated. Hmmm. So what's Canivet's Emerald doing over here in the middle of the Garden Emerald's range? We're not sure we have an answer but Ernesto tells us our numerous sightings of Canivet's this fall were the first recorded for the Ujarrás Valley.

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Like Garden Emerald, Canivet's is sexually dimorphic, but young males confuse the issue by masquerading as females. Thus, the white-throated, white-breasted, white-post-ocular-striped individual above can't be sexed as far as we know, but it's absolutely a Canivet's because of the reddish lower mandible. Based on the buffy edges to its head feathers, it also appears to be a very recent fledgling. (NOTE: The immature in this photo was captured in Guanacaste in February. We don't know if the species actually breeds in eastern Costa Rica.) The species breeds from southern Mexico to southern Costa Rica. The tail of the immature Canivet's Hummingbird (above) shows that distinctive tri-colored pattern also seen in female and immature male Garden Hummingbirds.

All text & photos © Hilton Pond Center

Although some hummers have common names that aren't very intuitive, there's not much doubt with the male Violet-headed Hummingbird, Klais guimeti (above). This three-inch species has a crown and gorget that are unquestionably iridescent violet--so brilliant the bird could almost be alled the "ULTRAviolet-headed Hummingbird." The black bill is straight and rather short, and both sexes show a noticeable post-ocular white spot.

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Violet-headed Hummingbirds are sexually dimorphic--the female has a bluish crown and grayish breast and throat--but the species is monotypic; i.e., it us the only hummingbird in its genus. It is fairly widespread, occurring from Honduras to Brazil. Both sexes show tiny white spots on tips of their tail feathers. This is one of those hummingbird species that forms leks during courtship; males gather at a communal spot and sing, apparently to attract females with a more-easily heard group chorus.

All text & photos © Hilton Pond Center

Yet another well-named species is the male Magenta-throated Woodstar, Calliphlox bryantae (above), whose gorget is so bright and metallic it almost hurts one's eyes.

All text & photos © Hilton Pond Center

From the side the male woodstar isn't particularly distinctive, with a green back and rather long tail (above). If it faces you in direct light, however, you'd better grab your sunglasses. The species is sexually dimorphic, with the female lacking the gorget and having a shorter tail. The big white patch on either side of the rump is an important field mark in both sexes.

All text & photos © Hilton Pond Center

The tail of the adult male Magenta-throated Woodstar is noticeably long and is cocked upward during rather slow flight. Conversely, the body is held horizontally, giving what some observers say is an "insect-like" flight profile. This species is endemic to Costa Rica and western Panama; our sightings this fall in the Chayote fields were the first recorded for the Ujarrás Valley.

All text & photos © Hilton Pond Center

Folks often ask us about our "favorite" hummer, and for obvious reasons we usually say we like Ruby-throated Hummingbirds because they've taken us places we never imagined. Nonetheless, we also have a marked preference for another aptly named species, the four-inch-long Blue-throated Goldentail, Hylocharis eliciae. Of all the kinds of hummingbirds we've handled through the years, this is the one that still takes our breath away. Green head, metallic blue gorget . . .

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. . . blood-red bill with black tip, rainbow-colored rump, and of course . . .

All text & photos © Hilton Pond Center

. . . a tail of precious gold! The degree and variety of iridescence in this species is indeed breath-taking. Blue-throated Goldentails are partly dimorphic, with the female lacking a blue gorget but still bearing those bright rectrices. This is another lekking hummingbird that is rather uncommon on the Caribbean slope, so we were pleased to find this colorful old friend we first met in Guanacaste in 2008. The species breeds from southern Mexico to Colombia. Our sightings of Blue-throated Goldentails this fall were the first recorded for the Ujarrás Valley.

All text & photos © Hilton Pond Center

By comparison to the other 12 trochilids were captured at Ujarrás, Ruby-throated Hummingbirds might seem a little plain--especially when some of the adult males we caught bore metallic "red" gorgets that had faded and worn to a bronzy color (above). That said, ruby-throats can claim one attribute that can't be said of any of the 50 other Costa Rican hummers: They're the only ones that undergo long-distance migration, fledging in North America and then flying up to 2,000 miles (or more) to the Neotropics--and back. It's possible some of Costa Rica's hummingbirds migrate over short distances-- which could explain, for example, how Canivet's Emeralds were showing up at Ujarrás within the breeding range of Garden Emeralds--but nobody else can hold a candle to the ruby-throat's seasonal movements.

All text & photos © Hilton Pond Center

Ruby-throated Hummingbirds are sexually dimorphic, with the female lacking a red gorget and having white tips on her outer tail feathers. All young males also have white-tipped tails, and some have female-like white throats.

All text & photos © Hilton Pond Center

That said, a significant number of immature males are adult-males-in-the-making (above); they exhibit pale-to-dark throat streaking and can have one or more red gorget feathers--especially by the time they get to Central American wintering grounds. By the time they return to North America to breed these young males have grown forked tails populated with pointy, dark-tipped feathers, and they have full red gorgets. By then they look like adult males because they are, and in the U.S. and Canada soon get down to the all-important business of defending territories and attracting females.

So that's our gallery of 13 hummingbird species we captured in mist nets among the Chayote fields at Ujarrás. We only banded Ruby-throated Hummingbirds--our permit from the U.S. Bird Banding Lab limits us to applying bands to Neotropical migrants--but we certainly enjoyed handling and photographing those other 12 highly colorful resident Costa Rican species that hit our nets. From a scientific staindpoint we were impressed with Canivet's Emerald, Blue-throated Goldentail, and Magenta-throated Woodstar--three species that had never been recorded for the Ujarrás Valley. With so many opportunities to observe, capture, and photograph so many kinds of hummingbirds, we'll certainly be going back and hope you'll join us sometime soon for an Operation RubyThroat expedition to the Neotropics.

All text & photos © Hilton Pond Center

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POSTSCRIPT: We've been working with Holbrook Travel before the holidays trying to lay plans for an Autumn 2012 trip to Ujarrás to continue our work with Ruby-throated Hummingbirds. We just heard from Debbie Sturdivant, Holbrook Travel consultant since our very first Neotropical trip, that she has worked out logistics and will be able to offer the expedition at an even lower price than last year. The nine-day trip will be $1,495 for all land costs, plus air fare. Alumni of previous Holbrook trips qualify for a $100 loyalty discount. We haven't had time to design and post a new itinerary yet, but the expedition will occur on 10-18 November 2012 and essentially follows the schedule outlined for the 2011 Ujarrás Trip. Note that a few spots are also still available on our 2012 Guanacaste Trip (2-10 February) to band and observe hummingbirds in western Costa Rica.