Wednesday, September 21, 2011
I spent two days last week camping and bicycling around the Hero Islands and Isle La Motte and was pleasantly surprised at the number of loons I observed from my bicycle seat. There were at least 12 loons along the east coast of the islands (known as the Inland Sea). What made the observations even more satisfying is that I was not intentionally searching for loons; they were just there when the roads came near the water. Thus, there were likely more than 12 loons in the area. I also heard yodeling, the male territorial call, coming from the Savage Island region. There have been reports of loons nesting on Lake Champlain, but we still have not confirmed any nests or chicks.
Back in 2002, I spent nearly 3 weeks in June and July conducting loons surveys on Lake Champlain, and I only observed 2 or 3 loons in this entire NE section of the lake. With the help of 25 volunteer observers on Loonwatch day, we did estimate that there were at least 30-40 adults and 15-20 subadults on the entire lake during mid-summer. Now in mid-September, it could be that loons are already moving to Lake Champlain in preparation for migration, especially non-breeders and breeders without chicks. However, most loons really do not start moving from their territorial waters until later September and October.
Where do these loons come from? We know that one loon from the Adirondacks with an implanted satellite transmitter stopped on Lake Champlain for a day on its way to the Cape. Since loons tend to eventually return to their natal lake areas, I would guess that most loons observed on Lake Champlain are either from the Adirondacks or Quebec. Vermont loons likely stay to the east side of the Green Mountains. This summer we captured a loons in Williston (stuck on a water retention pond at Tafts Corners shopping center) that was very small indicating it was from central or northern Quebec. Loons become smaller the further they are from coastal areas. Ted Murrin, an avid Vermont birder, has counted over 500 loons in one day migrating along the shores of Lake Champlain in late October.
Next time you are on the shores of Lake Champlain, keep your eyes peeled (and enter your sightings on VT ebird). During the next two months, scores of loons and other birds will be flying south over Lake Champlain's waters. ** Eric Hanson, Vermont Loon Recovery Project Coordinator
Friday, September 16, 2011
Juan Carlos is Spanish by birth and received his undergraduate degree from the Universidad Autonoma de Madrid in 1980. He has since spent a diverse career as a conservation biologist, with a concentration in field ornithology, throughout Latin America, but mainly in Nicaragua. His work has included not only research (he received a PhD from U. Washington in 2008, studying the role of organic shade coffee production in conserving biodiversity in Nicaragua), but protected areas management, training of conservation professionals, and implementation of on-the-ground conservation initiatives. Needless to say, this background is extremely relevant to IBTCG's needs for Bicknell's Thrush-related conservation throughout the Greater Antilles. Juan Carlos is passionate about conservation and ornithology, and he is eager to share that passion and his knowledge with diverse groups of people.
Juan Carlos recently moved to Port-au-Prince, Haiti, a fortuitous relocation that places him squarely in the heart of IBTCG's Greater Antillean focus area. Although we expect his first few months to be concentrated on Hispaniola, which harbors most of the global wintering population of Bicknell's Thrush, ultimately Juan Carlos will initiate IBTCG activities on Jamaica, Puerto Rico and Cuba.
This is an exciting development for IBTCG, for montane forest conservation in the Greater Antilles, and for the Caribbean bird conservation community. Juan Carlos will spend 2-3 weeks at VCE next month, visiting numerous IBTCG partners around the Northeast, before tackling our ambitious agenda in the DR and Haiti. We welcome him to VCE and the IBTCG!
Thursday, September 15, 2011
VCE's final mist-netting foray to the Mansfield ridgeline on Monday
evening and Tuesday morning featured fine weather, a full moon, and
stellar avian activity. As is usual in mid-September, Bicknell's
Thrushes showed a resurgence of vocal activity. Calling was frequent,
especially at dusk and dawn, and several birds sang. Kent McFarland
even heard dusk flight songs. With only 15 nets, we ended up with an
all-time single-visit record of 20 Bicknell's Thrush captures - 13
immatures (young-of-the-year) and 7 adults (5 retraps from earlier in
the summer). Most responded strongly to playback, suggesting that all
age classes may be prospecting for turf and/or mates in anticipation of
being back on the mountain next spring. We know site fidelity of both
adult males and females is strong (60-65% from one year to the next), so
it may make sense for individuals to make their presence known just
prior to migrating south.
Other birds banded:
Swainson's Thrush 2
Hermit Thrush 1
Blackpoll Warbler 6
Yellow-rumped Warbler 10
White-throated Sparrow 2
Other birds captured but not banded:
Sharp-shinned Hawk 1 immature male
Red-eyed Vireo 2
Ruby-crowned Kinglet 2
Black-throated Blue Warbler 6
Black-throated Green Warbler 3
Dark-eyed Junco 4
Common Raven 16 cavorting over and around the summit, the most we have
ever seen together in 20 years working on Mansfield
Cedar Waxwing 12+
Golden-crowned Kinglet 4
White-winged Crossbill 6 calling overhead
A memorable finale to our 2011 field season!
Friday, September 09, 2011
They discovered that the Appalachian tiger swallowtail, Papilio appalachiensis, evolved from mixing between the Eastern tiger swallowtail, P. glaucus, and the Canadian tiger swallowtail, P. canadensis. The Appalachian tiger swallowtail rarely reproduces with its parental species and is a unique mixture of the two in both its outward traits and inward genetic makeup.
Their research is published in PLoS Genetics.
"How new species form is one of the central questions in evolutionary biology," says Krushnamegh Kunte, a post-doctoral research fellow at Harvard who began his research as a graduate student at The University of Texas at Austin. "Hybrid speciation is more common in plants, but there are very few cases in animals. This study may create the fullest picture we have to date of hybrid speciation occurring in an animal."
Kunte and colleagues studied three of the eight species of North American tiger swallowtail butterflies. These large insects are generally recognized by yellow wings with black stripes and small "tails" on their hind wings.
Of the three species, Eastern tiger swallowtails prefer warmer climes and lower elevations, and the females come in two different forms. They are either striped (yellow and black) or almost entirely black, the latter mimicking a poisonous butterfly called the Pipevine swallowtail, Battus philenor. Canadian tigers are only striped yellow and black, and found in cooler habitats at higher latitudes and elevations.
The Appalachian tiger exhibits a mix of those traits. It shares an affinity for cooler habitats with the Canadian tiger, while sharing the ability to mimic the black Pipevine swallowtail with the Eastern tiger.
Digging into the butterflies' genomes, the scientists found that the Appalachian tiger inherited genes associated with cold habitats from males of the Canadian tiger, and inherited a gene for mimicry from Eastern tiger females.
They also found that the Appalachian tiger's genome has become significantly distinct from the genomes of its two parental species, even though the butterflies come into contact with each other in the wild (the Appalachian tiger's range nudges against the Canadian tiger in the northern Appalachian Mountains and against the Eastern tiger in the lower elevations surrounding the mountains).
The conventional view of speciation is that one species splits into two over time. With time, the new "sister" species become more and more reproductively isolated from each other.
In the case of hybrid speciation, new species are formed when two species interbreed to create viable hybrids that then evolve on their own. This can occur when two young species haven't yet evolved over a long enough period to be completely reproductively isolated.
Kunte says this is probably the case with these tiger swallowtails. The Eastern and Canadian tigers diverged from each other a mere 600,000 years ago. The Appalachian tiger seems to have diverged from both the parental species only about 100,000 years ago.
"That's not a very long time," says Kunte, "but still we found that the Appalachian tiger has been isolated long enough to have a different appearance and genetic makeup than its parent species."
As for identifying the species in the wild, Appalachian tigers are twice the size of Canadian tigers. Kunte says it's a bit more difficult to distinguish the Eastern and Appalachian tigers. The Eastern tiger has more blue on the hind wing and a spotted yellow band on its fore wing underside compared with a solid broad band on the Appalachian tiger.
"Once you train your eyes to tell them apart," says Kunte with a confidence that comes from years of collecting butterflies, "they are relatively easy to distinguish."
Source: University of Texas - Austin
Photo: A female Appalachian tiger swallowtail. Credit: Krushnamegh Kunte.
Kunte's coauthors include Marcus Kronforst at Harvard, and Kunte's graduate advisers Larry Gilbert and Tom Juenger at The University of Texas at Austin. The research was funded in part by the National Science Foundation and the National Institutes of Health.
Thursday, September 08, 2011
While it is tempting to believe that Bryan's Shearwater may nest (or have nested) in the Midway Atoll region, the fact that the sole know specimen was discovered there is inconclusive evidence since many seabird species regularly prospect colonies far from their primary breeding sites. In other words, the existing specimen could have simply been a prospector from a colony elsewhere in the Pacific. In any case, this discovery will put marine scientists on notice to the fact that perhaps this obviously rare species might still exist.
For more information about Bryan's Shearwater, see: