22 October-7 November 2005

Installment #291---
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Join us for another
Winter Hummingbird Expedition to Costa Rica
in February 2006


All text, maps & photos © Hilton Pond Center

The White-eyed Vireo, Vireo griseus, is a relatively common Neotropical migrant that breeds in the eastern third of the U.S. and sometimes overwinters in southeastern coastal states rather than flying all the way to Mexico and Central America. At first glance, the bird in the photo above might appear to be an immature White-eyed Vireo whose iris has not yet acquired the character that gives the species its common name. It's a vireo all right--the bill shape and tiny hook and notch at the tip of the upper mandible are helpful diagnostics--but there's much too much yellow in the lores and the thin eye-ring of the White-eyed Vireo is missing. In fact, it's not even a bird from Hilton Pond Center but one from the western Caribbean, where we were fortunate enough to spend 14 days in October and early November at the behest of ProAves, a South American environmental group whose mission is to protect Colombia's native birds--as well as many avian species we North Americans happen to share with them for part of the year.

All text, maps & photos © Hilton Pond Center

Most of Colombia is on the northwestern corner of the South American continent, of course, bordering Panama and with coastlines on both the Pacific Ocean and Caribbean Sea (see satellite composite photo above). But in spite of an old dispute with Nicaragua, Colombia also lays claim to the islands of San Andres, Old Providence, and Santa Catalina, an archipelago 400 miles northwest of Colombia and only 100 miles east of the Nicaraguan coast. Collectively, these Colombian islands make up the Seaflower Biosphere Reserve, recognized by the United Nations as an area of "coastal ecosystems promoting solutions to reconcile the conservation of biodiversity with its sustainable use." San Andres is a small coral outcropping--just one mile wide by seven miles long (see satellite photo at right)--but because of its location as the western most island in the Caribbean it is not only permanent home to endemic species but also a stopover point for great numbers of migrant birds on their way further south from North and Central America. The San Andres Vireo, Vireo caribaeus--our mystery bird at the top of the page and in the photo just below--is not only endemic but endangered and serves as a "poster child" illustrating a critical need for on-going habitat protection on the island.

Despite its small size, San Andres has more than 70,000 human residents concentrated primarily on the north end, as well as tens of thousands of tourists who flock to the island from countries around the world. We suspect most U.S. citizens had never heard of San Andres Island--at least not until it made national news as Tropical Storm Beta headed in its direction during the last week in October. (More about that later.)

All text, maps & photos © Hilton Pond Center

ProAves, a non-profit organization, is keenly aware of the need for further study of avifauna within Colombia's borders and has assumed the role of raising professional standards in ornithological studies. With financial and in-kind support from a number of international organizations, ProAves invited more than 60 Colombian nationals to San Andres for 14 days of instruction about bird conservation techniques. Participants ranged from 19-year-old college students to experienced conservationists in their mid-50s. The primary focus of the workshop was on using bird banding as a tool to inventory and monitor resident and migratory bird populations, and our specific responsibility through Hilton Pond Center and Operation RubyThroat: The Hummingbird Project was to teach participants how to safely capture, handle, and band hummingbirds.

All text, maps & photos © Hilton Pond Center

Considering that Colombia has more than 150 hummingbird species and that hummers may comprise 30% to 50% of all net captures at some Colombian research sites, students were especially eager to learn about hummingbird handling techniques, so one of our first tasks was leading a palm-shaded general session on trapping and banding hummers (above). With regard to our own research, we also wanted to see if the handful of eyewitness reports of Ruby-throated Hummingbirds on San Andres were true; if we could capture and band a ruby-throat, it would be the first verified record of the species for any South American country--even though the Caribbean island is in South America only in the political sense, not geographically.

San Andres is indeed a tropical island, but our time there was no idyllic vacation. We departed Charlotte for Miami on 19 October and went on to Panama City, Panama, to spend the night in an airport hotel, sharing our room with a family of small geckos. Next day we took the short, one-hour flight to San Andres where workshop organizer Andrea Morales Rozo was waiting for us at noon as we cleared immigration and customs. From the airport we took a taxi to Red Crab Apartments (above left), a three-story beachfront structure not unlike many modern vacation homes built along the South Carolina coast. Our second-floor balcony faced east, so we could see the beach, the sunrise (or moonrise, right)--and what were normally two-foot waves that broke across the coral reef not far offshore. Half the students, instructors, and ProAves staff stayed at the Red Crab, while the rest were quartered a mile or so away at Pepper Hill Apartments--positioned on a 150-foot ridge that was the highest point on San Andres. Each apartment had a small swimming pool, but we're forever grateful we were assigned to Red Crab because--unlike Pepper Hill--it was air conditioned dusk 'til dawn, a nice amenity when typical daytime highs were 85 degrees and nighttime lows were still near 80.

All text, maps & photos © Hilton Pond Center

The first afternoon on the island everyone gathered for introductions and an organizational meeting at the National University of Columbia, whose small, modern San Andres campus included a computer-equipped classroom just large enough to accommodate our 60 workshop participants, plus trainers and staff. From there we took an ancient yellow school bus to Miss Lidia's (above), the open air restaurant where we typically gathered for lunch and supper. Meals ALWAYS included an enormous pile of white rice--usually accompanied by fish or meat, a vegetable of some sort, and a variety of fruit juices. On cool, rainy days--of which we had several--a bowl of soup warmed us up a bit. (You'll note in the photo above a motor bike driving past Miss Lidia's dining emporium. We were surprised to encounter what must have been thousands of these vehicles scooting around San Andres' roads, of which there were only a few.)

All text, maps & photos © Hilton Pond Center

Our typical work day for the San Andres banding workshop began promptly at 4:30 a.m. with a dream-shattering knock on the door. (On overcast days we started about a half-hour later.) At Red Crab Apartments, Paul Salaman of the American Bird Conservancy was always the first instructor to roll out because his responsibility was to assemble and supervise a rotating crew of students in erecting a dozen or so mist nets in nearby fields and mangrove swamps (above), unfurling them in pre-dawn darkness. Often "net-runners" such as Angelica Hernandez (left) were already catching birds and carefully placing them in cloth bags as the sun came up at about 6 a.m., so it was important for the rest of us trainers to be at the banding tables early with our tools and instructional materials laid out as we helped small groups of students learn to handle, identify, and band birds.

The other non-Colombian instructors with us at the Red Crab site were experienced "bird ringers" on loan from their organizations in Great Britain: Nick Bayly of The Wetland Trust and Mark Grantham of the British Trust for Ornithology. Pepper Hill instructors included Americans Bob Frey (below, left, with student) and Keith Larson--both of Klamath Bird Observatory, Pablo Herrera of the Redwood Science Laboratory, and Danielle Kaschube of the Institute for Bird Populations--plus Sergio Vilchez Mendoza from Nicaragua. ProAves staffers Andrea Morales Rozo, Maria Isabel Moreno, Andrea Pacheco, and Alonso Quevedo also were instructors, with the incomparable Camila Gomez--just in from a six-month U.S. Forest Service internship in Oregon--serving in a critical role as our main translator. (Fortunately, many of our Colombian students understood English when they read it or heard it spoken slowly, but we kept wishing we had taken Spanish in college rather than French and German. As it was, we got our point across most of the time as a "multilingual mime.")

All text, maps & photos © Hilton Pond Center

The overwhelming majority of birds we netted and banded on San Andres were hatch-year Neotropical migrants produced from nests in the forests of North America. Workshop participants got intimately familiar with many members of "our" Wood Warbler Family--especially Tennessee Warblers--and altogether we netted 26 species of parulids. Every bird captured was assigned to a student who first identified it using field guides and then undertook the arduous task of trying to age and sex each individual bird using Peter Pyle's encyclopedic Identification Guide to North American Birds. This big black book--studied below by students Vladimir Sandoval and Monica Ramirez--is a synthesis of many published papers about many species and serves as the "bird bander's bible." It lays out the minute details of measurements, plumage, molt, and other external characteristics that help a bander know how old a bird is--or at least whether it's this year's fledgling or an adult.

All text, maps & photos © Hilton Pond Center

Age determination by molt is not nearly as easy as it might sound, but the Colombian students worked very hard EVERY day to learn the concepts and the terminology--in English, no less! Generally, a young bird--at least among passerines--hatches out with "natal down," but through a "pre-juvenal molt" quickly acquires the wing, tail, and body feathers it bears when it leaves the nest. This entire "juvenal plumage" comes in at the same time and rate, so a fledgling's feathers all have the same consistency and amount of wear.

All text, maps & photos © Hilton Pond Center

Shortly before migrating, recent fledglings of most North American passerines then go through a partial "first pre-basic molt," acquiring a "first basic plumage" that typically includes new secondary covert feathers that overlap the bases of the secondary wing feathers. (The hatch-year Yellow Warbler in the photo above is bringing in new secondary coverts that are still partly ensheathed; it has also already molted most of its median coverts that overlap the secondary coverts.) These same birds usually keep their juvenal primary coverts (the short, dull feathers to the left of the photo above), so by comparison the secondary coverts look newer and fresher and are better constructed than the primary coverts--a contrast that is the sure sign of a young bird. Tails also may provide a clue about a bird's age, since juvenal rectrices (tail feathers) are usually pointed and loosely structured--as in the young Hooded Warbler below right--while those of adults are rounded or truncate and better-formed.

Later molts lead to other plumages--the "first pre-alternate molt," for example, leads to the "first alternate plumage"--but sundry species show diverse variations on the theme. Based on this rather cursory explanation of molts and plumages, you can understand why it takes a while--perhaps years--to truly master ageing birds by looking at their feathers, and why it was essential that instructors at the San Andres training session work closely and intensively with the students individually and in small groups. (We haven't even mentioned that it's always good to confirm your plumage-based conclusions about a bird's age by gently spreading the head feathers to look at the amount of calcification that has occurred in the bird's cranium, so we taught all the ProAves workshop participants how to "skull," too!) Like we said, NONE of this is easy.

All text, maps & photos © Hilton Pond Center

So that's what it was like most days on San Andres. Rise and shine at 4:30 a.m., deploy the mist nets, extract birds, return them to the banding tables, identify and band and examine and measure each bird and age it by a combination of plumage and skull characteristics, record the data, discuss unusual permutations of plumage with the group, release the bird, go make another net check, start the process anew, and MAYBE have time to grab a bite of breakfast while we worked. Sometime around 11:30 a.m. the crew that had erected the nets that day went out to take them down, so usually we wound up the practical portion of our work by about noon or so. Then it was off to Miss Lidia's for lunch and a quick staff discussion about the morning's accomplishments. Many folks took a short siesta after returning to their respective apartments, with a few stalwart souls--unfortunately, not the Hilton Pond contingent--going out for some snorkeling. We wanted to snorkel and just couldn't find time, but we did slip away for a exploratory photo session one afternoon. That day we recorded what to us seemed to be an odd juxtaposition: Two woodland warblers from North America--a Blackburnian and a Bay-breasted (above)--foraging on an algae-encrustred coral outcropping on the saltwater beach at San Andres, just down shore from a flock of sandpipers and Ruddy Turnstones! Meanwhile, overhead we almost always could see the unmistakable silhouette of one or more Magnificent Frigatebirds (above left).

Most days by 4 p.m. we boarded the old yellow school bus for the university, where students heard lectures from staff and instructors about everything from the history of ProAves to Operation RubyThroat: The Hummingbird Project to conservation of aquatic birds in Colombia, and almost every afternoon there was a least one short illustrated talk about--guess what?--molts, plumages, and bird ageing techniques. By 7 p.m. or so we were off for Miss Lidia's and a sumptuous supper, after which we had a few hours to socialize before hitting the sack and dreaming about--what else?--plumage and molt.

All text, maps & photos © Hilton Pond Center

We did manage to net and band hummingbirds during our days on San Andres, but we regret none were migratory ruby-throats. Nonetheless, it was fulfilling and useful to be able to handle 39 Green-breasted Mangos, Anthracothorax prevostii--a species we had encountered last winter on our hummer banding trips to Costa Rica. By comparison to the ruby-throat, a mango is one big hummingbird--almost twice its size. A male that has completed his first full molt is metallic green all over (above), except for an iridescent purple tail and a velvety blue-black stripe down the center of the breast. Adult females have a white belly with a thin black stripe, while young birds of both sexes are similar to the female but with varying amounts of rufous on the throat and upper breast (right). We found it interesting that most of the mangos we captured were caught in nets beside an unknown leguminous vine with pinkish flowers (below) that appeared to be a primary food source for island hummers. This particular plant grew freely in much of the open areas around the main Red Crab banding site, blanketing shrubs or trailing across otherwise open ground--sort of like Kudzu but far less pernicious.

All text, maps & photos © Hilton Pond Center

It was particularly nice to capture more than three dozen mangos because it gave all interested students an opportunity to observe and work with hummingbirds--something they would be doing regularly on their study sites back on the Colombian mainland. There is a small, apparently unstudied resident population of Green-breasted Mangos in northern Colombia, but the principles of safe handling are the same for all hummer species--and our students learned those principles well. Several workshop participants with previous banding experience returned home after the workshop to initiate or continue studies of endangered and recently rediscovered hummingbird species in Colombia, including birds with exotic names like Colorful Puffleg and Dusky Starfrontlet.

All text, maps & photos © Hilton Pond Center

In all, instructors and students captured, banded, identified, aged, sexed, and measured 2,761 birds at the Red Crab and Pepper Hill sites during our 14-day workshop on San Andres, including several individuals of a very misleading version of the Yellow Warbler, Dendroica petechia (above)--guaranteed to befuddle even experienced bird banders unfamiliar with the unusual colors of this particular race. We also know how many species were captured: exactly 72, seven of which were NOT on the official San Andres checklist. (The new birds were: Gadwall; Willow, Alder, and Least Flycatcher; Veery; Yellow-throated Vireo; and Nashville and Canada Warbler--all birds from North America.) Our most common resident species was the Bananaquit, Coereba flaveola, which the locals call "wish-wish." These little black and yellow birds with red gapes were forever hitting our nets (left), but they are quite sturdy and handled well. The good news was that the Bananaquit is ideal for showing molt differences between immatures and adults; the bad news is that we captured several of the same spunky individuals over and over and over again, which gave us intimate understanding of Bananaquit molt limits but slowed us down on banding new birds.

All text, maps & photos © Hilton Pond Center

It's worth mentioning that in addition to all their other attributes, we also examined every bird we captured for stored fat and status of their breast muscles. Three resident species--Bananaquits; Black-faced Grassquits, Tiaris bicolor (above); and representatives of an endemic race of Black-whiskered Vireo, Vireo altiloquus (below)--were healthy and with good muscle mass, but the vast majority of migrant birds we caught on San Andres were completely devoid of fat and had depleted pectoral muscles. In other words, these birds were nearly spent from the rigors of migration, implying that if San Andres hadn't been where it was, the birds might have been unable to go much further and probably would have perished. And, since almost none of the migrants were adults, the implication is that at least some of these immature birds on San Andres may have been lost and away from their species' optimal migration route(s). Every morning we found numerous dead birds on the ground; some had been hit by vehicles, but others had simply died from exhaustion after they arrived sometime during the night.

All text, maps & photos © Hilton Pond Center

There's also a good chance these wayward migrants were affected by all the hurricane activity in the Gulf of Mexico this fall. Of particular interest was Tropical Storm Beta--the Atlantic Basin's record-breaking 23rd named storm of the season--which brought attention to San Andres on many U.S. newscasts when the tiny island was sitting directly in Beta's path. From our second floor balcony at the Red Crab Apartments we could see Beta approaching for a couple of days--a very dark blot on the eastern horizon that came straight toward us and whipped up south-flowing winds along its western edge. As Beta advanced, local officials on San Andres responded quickly and admirably, distributing Spanish-language flyers (right) to virtually every island resident with instructions on what to do if the storm came ashore. On 28 October, local police and Roman Catholic churchmen collaborated to convince about 500 tourists and 200 locals living at water's edge to evacuate to higher ground, just in case Beta brought a tidal surge. Most businesses and residences along the beach are not built to withstand gale force winds and high waves, so this limited evacuation along parts of the island's eastern shore was a prudent course of action.

All text, maps & photos © Hilton Pond Center

To make a long story a little shorter, Beta did whip up some 65 mph wind gusts, bring a few days of torrential rain, and raise normal ocean swells to ten feet or so (above), but for the most part the storm left San Andres--and all the workshop participants--unscathed. Although we lost a few days of netting and banding work because of weather, we were grateful Beta suddenly turned northward and passed us by--probably less than 20 miles to the northeast (see satellite photo below). The eye of the storm did overrun neighboring Old Providence and then slam the Nicaraguan mainland as a Category 2 hurricane on 30 October but--fortunately--with minimal loss of life.

All text, maps & photos © Hilton Pond Center

It will be very interesting to see if even ONE of those birds we banded after it was blown onto San Andres by Beta continues on to South America after regaining muscle and fat, and/or if any of our banded birds are recaptured back in the U.S. or Canada in subsequent years.

All text, maps & photos © Hilton Pond Center

One of our more interesting non-avian encounters on San Andres came as we were helping students identify birds at the banding table. A few feet away a small creature was undulating across a sidewalk, and we thought at first it was a worm, but it bore a yellow spot on both head and tail. Upon closer examination we saw it also had scales, so it turned out to be a tiny, skinny snake (above). The snake's eye itself was covered by a scale, and this miniature reptile had a massive overbite (below left). Turns out it was a Little Blind Snake, probably a Leptotyphlops sp., which spends most of its life in termite mounds and ant hills. Only 4" long and an eighth of an inch in diameter, this fully grown reptile is among the smallest snakes on earth. Interestingly, we heard from an island local that domestic chickens love to peck and swallow these tiny serpents, but that the snakes pass through the chicken's digestive tract unscathed--only to be eaten again and again. We do believe inquisitive and hungry fowl will consume blind snakes, but we're a bit skeptical about the rest of the story.

We had one other encounter on San Andres that was even more memorable--and painful. During our very last work session of the 14-day workshop we were processing the final batch of birds at the banding table, which we had placed in the shade of one of the island's omnipresent coconut palms. As we were standing there discussing molt sequences with a student, we felt a sudden sharp pain on top of our head and--even though it was broad daylight--immediately began to have visions of planets, stars, and constellations. This celestial event came about because--and please pardon the pun--a "palm-sized" coconut (actual size below) had broken from its cluster and plummeted 20 feet or so until it ran into our skull. The coconut, perhaps loosened by the previous week's tropical storm, bounced off our cranium and then raised a small welt when it hit a student's shoulder, so you can imagine what it did to its initial target. Concerned and helpful students quickly seated our woozy body in a chair, ran for ice, and expressed sincere concern for several hours to make sure we were okay. The really bad thing was that the coconut broke open on contact--an embarrassing commentary on the hardness of the hapless victim's skull--and added insult to injury by spewing coconut milk across the banding table. We're just glad the two-pound nut was a baby and not one of those mature, ten-pound lunkers (above right). By the way, we moved the banding table into the open after that, carefully noting in our journal--in English AND Spanish!--that future workshops should avoid setting up under killer coconut trees.

All text, maps & photos © Hilton Pond Center

Despite that unexpected bop on our head from a coconut and our potentially devastating encounter with a hurricane, there's no doubt our time on San Andres was enjoyable and worthwhile. The Colombian students were courteous, friendly, intensely interested, and hard-working. And--as always happens at these kinds of events--the instructors got to swap techniques and learn from each other. We personally enjoyed informal talks we had with students who openly expressed their appreciation for a unique learning experience--especially because it would empower them to do an even better job of taking care of their country's treasure trove of birds, both in Colombia proper and on San Andres. In return, we Americans should be grateful to all these students for their dedication to Neotropical conservation activities. After all, many bird species they're conserving--from Scarlet Tanagers to Hooded Warblers to Empidonax flycatchers--are not "our" birds or "their" birds but "everyone's" birds that spend half the year in the U.S. and the rest of their time in the tropical forests of Central or South America. So thanks, ProAves, for inviting Hilton Pond Center and Operation RubyThroat to contribute to your efforts, and thanks to all you workshop students for your friendship, enthusiasm, and hard work. We wish you well!

All text, maps & photos © Hilton Pond Center

POSTSCRIPT: The name "San Andres" translates into English as "St. Andrews"--which we find rather ironic because earlier this year we went to St. Andrews in New Brunswick, Canada to teach at the National Wildlife Federation's Family Summit. As a result, we've established a new goal of observing natural history phenomena in as many places as we can find with "St. Andrews" in their name. The easiest one will be St. Andrews SC, a suburb of Columbia--not Colombia--about 75 miles to the south of York SC; St. Andrews, Scotland, will be a little harder. If you're aware of other nature-related locations named after "St. Andrews," please let us know.

All text & photos © Hilton Pond Center

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Be sure to scroll down for an account of all birds banded or recaptured during the week, plus other nature notes of interest.

"This Week at Hilton Pond" is written & photographed
by Bill Hilton Jr., executive director of
Hilton Pond Center for Piedmont Natural History.

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Vagrant & Winter


22 October-7 November 2005

White-throated Sparrow--1

* = New species for 2005

0 species
0 individuals

58 species
1,245 individuals

(since 28 June 1982)
124 species
46,552 individuals

(with original banding date, sex, and current age)

--Due to an extended out-of-the-country bird-related excursion that began 19 Oct
(see above), banding time at Hilton Pond Center was limited to one day in November and netted only one bird.

--In our absence, and despite the tropical deluge we experienced on San Andres, no precipitation fell on Hilton Pond Center, meaning the water level on the pond itself is fast receding. As of 7 November, the gauge read three feet below full pond, with no rain in sight.

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© Hilton Pond Center

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