On Being a Responsible Bird Feeder

There are 46 million birdwatchers in the United States. Vermont ranks second among states with the highest per capita number of birdwatchers (44%). And the majority of us have backyard bird feeders. But how often do you clean your feeders? What are the risks of a dirty feeder? And what do you do if a sick bird visits your feeders?

A recent discussion on the Vermont birdwatching listserv provides some answers. A birdwatcher in Norwich noted a lethargic, puffed up Common Redpoll at her feeder. After posting it to the bird listserves, it was diagnosed as probably having Salmonellosis. Salmonellosis is caused by a bacteria transmitted through fecal contamination of food and water or directly from bird-to-bird. Savvy birdwatchers quickly advised that the feeders be removed and cleaned and the bird captured and brought to a licensed rehabilitator.

The winter months pose obvious challenges for birds. They need to find enough food during the daytime to keep their metabolism going throughout the long, cold nights. This can be difficult when there is so much snow and ice like we have seen this winter, and many birds search for the easiest sources of food—bird feeders. This brings diseased birds in close contact with one another and can lead to outbreaks.

Responsible feeder watchers recognize the symptoms of common avian diseases:

• Salmonellosis—birds are puffed up, lethargic, thin, and may have swollen eyelids
• Conjunctivitis (AKA House Finch Eye Disease)—eyes are red, swollen, runny, and may be crusty or even swollen shut
• Avian Pox—this virus results in wart-like growths appear on bare parts such as around the eyes, bill, legs, and feet
• Aspergillosis—a fungus that attacks a bird’s respiratory system, outwardly causing difficulty in breathing and walking, emaciation, thirst, and sometimes the eyes appear opaque
• Trichomoniasis—a protozoan carried by pigeons and doves and spreads through water sources that causes lesions in the mouth and prevents birds from being able to close their bill

West Nile Virus is spread in birds by mosquitoes and birds don’t show symptoms until advanced stages, while Avian Influenza (H5N1) has not been reported anywhere in the Americas.

Regularly cleaning your feeders is the key to preventing the spread of avian diseases. Clean feeders every two weeks with soapy water followed by soaking in a 1:9 bleach solution. Let them dry thoroughly before refilling. Remove seeds dropped on the ground and consider moving your feeders on a regular basis. Bird baths and hummingbird feeders should be cleaned every time you fill them.

Watching birds in our backyards can be an enjoyable and even educational experience. Responsible feeding helps ensure that birds will keep returning to your backyard throughout the seasons, and gives you peace-of-mind in knowing that you are not contributing another challenge to their survival.

You can explore all the birds reported last week in Vermont and add your own sightings at Vermont eBird.

-Julie Hart

Troubles Far From Home

Separated by nearly 3,000 kilometers (1,800 miles), our own Green Mountains and the Dominican Republic’s Sierra de Bahoruco would seem to share little in common. However, each provides crucial habitat for Bicknell’s thrush, one of North America’s most rare and vulnerable songbirds. The island of Hispaniola, shared by the Dominican Republic and Haiti, is home to an estimated 90% of the global wintering population of this species, which may number as few as 20,000 individuals. These two countries face unrelenting loss of native habitats from intense human population pressures. Only 1% of Haiti’s original forest cover remains, while 10% of the DR’s forests tenuously persist. As the winter stronghold of Bicknell’s thrush, Hispaniola

is thus key to long-term conservation of this species.

I just returned from Sierra de Bahoruco, where the Vermont Center for Ecostudies has spent the past 14 winters attempting to unravel the elusive winter ecology of Bicknell’s thrush. Although we have found the species inhabiting dense broadleaf forests from sea level to >2,000 meters elevation, most intact habitats occur in mountainous areas, removed from the reach of humans. Our field research has revealed some fascinating and important insights. Foremost among these is that male and female Bicknell’s thrush appear to segregate by habitat type. In undisturbed, primary forests of Sierra de Bahoruco, males outnumber females by a 4:1 ratio. Both sexes maintain discrete territories throughout the winter, and insect food resources are relatively rich in these forests, which we believe represent “optimal” winter habitat for Bicknell’s thrush.

A different situation exists at our study site in the Cordillera Septentrional, a mid-elevation, much wetter area that features more disturbed, secondary broadleaf forest with a relatively open understory. Here females slightly outnumber males, and birds appear to feed more heavily on fruit, a generally lower quality food than insects. We suspect that these forests constitute “suboptimal” habitat for Bicknell’s thrushes, and that, because suitable habitat is limited islandwide on Hispaniola, females may have few options but to inhabit them. The consequences for female survival could be pronounced, with effects on the entire species’ viability. Adding insult to injury is our recent discovery that introduced rats may cause significant mortality during winter, even in the relatively pristine forests of Sierra de Bahoruco.

An intriguing, but troubling, link may exist between these wintering grounds events and the breeding ecology of Bicknell’s Thrush. VCE’s work on Vermont peaks has confirmed a breeding adult sex ratio of 2.2 males per female and a very unusual mating system, in which >75% of nests are attended by two or more males, with highly mixed paternity in broods. What is behind this male-biased sex ratio? We fear that overwintering females may be taking the hardest hit during the annual cycle. The story is complex, with more questions than answers, but the message is simple: effective conservation of a migratory species requires careful attention to both ends of its range.

Birding highlights of the past week included possible early vanguards of the spring migration: a Double-crested Cormorant off Charlotte, pairs of Rusty Blackbirds in both Danby and East Dorset, and two Red-winged Blackbirds in Danby. While these may simply be hardy individuals that overwintered in Vermont, they lend hope that lengthening days will soon spur a steady flow of northward returning birds. Other notable birds last week included single Peregrine Falcons in Middlebury, Weybridge and Burlington, a Belted Kingfisher in Hartland, and six Red Crossbills in Newport. This later species is always rare in Vermont and was an especially nice find in a year when crossbills have been poorly represented in the winter finch invasion that has delighted so many birders.

You can explore all the birds reported last week in Vermont and add your own sightings at Vermont eBird.

Mysterious bat disease confirmed in Dorset cave

A new mysterious and deadly illness of bats has struck New England’s largest bat cave, a cavern in a Dorset mountain where 23,000 bats spend the winter, a state wildlife biologist confirmed today. Read more at Burlington Free Press....

Meet the Scientists: Climate Change Impacts on New England Ecosystems

Representatives from Collaborative member institutions attend day-long professional development programs, meeting with scientists to discuss the latest research findings, methodologies and analytic techniques that scientists use to unravel human versus natural impacts on climate. This dialogue also allows scientists to learn more about how informal educators present complicated subject matter to the public in “digestible bits.”

Climate Change: Impacts on New England Ecosystems
March 19, 2008, 10 - 3.
Hosted by The Vermont Institute of Natural Science, Quechee, VT. Cost: $15 includes lunch.

• “Life in the Clouds: Potential Effects of Climate Change on Montane Fir Forests in the Northeast”
  Kent McFarland – Research Biologist, Vermont Center For Ecostudies
• “Projected Climate Change in New England: Impact to Riparian Wetlands"
  Michael Simpson – Wetlands Scientist, Antioch New England University
  

Download event flyer here (PDF file).

REGISTER TODAY - $15 includes lunch. Space is limited.

VCE Biologists Present Work at Partners in Flight Conference

VCE biologists attended the 4th International Partners in Flight Conferencet held on 13-16 February in McAllen, Texas. The conference theme was "Tundra to Tropics: Connecting Birds, Habitats and People", which will be shared with International Migratory Bird Day for 2008. The focus of the conference was international connections of all sorts that further bird and habitat conservation throughout the Western Hemisphere. VCE biologists have been active particpants of Partners in Flight for over a decade.

Chris Rimmer and Kent McFarland were invited to present a lecture on Bicknell's Thrush population limitations in the Dominican Republic. VCE biologists began field studies to assess the distribution, habitat use, and conservation status of Bicknell's Thrush in the Dominican Republic in December of 1994. Ten years and nearly 20 visits later, we are spearheading collaborative, island-wide efforts to protect birds and their habitats. Our current work integrates field research and monitoring with local training, outreach, and capacity building.

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Dan Lambert and Kent McFarland presented information on how their Bicknell's Thrush breeding habitat model and map has been used for conservation. A VCE poster on Bicknell's Thrush and atmospheric pollution was also shown.

We were able to do some excellent birding in the Rio Grande valley. Many of the sites we visited are part of the World Birding Centers. We saw many exciting lower Rio Grande specialties like Green Jays, Great Kiskadee, Red-crowned Parrot, and this Common Paraque shown below roosting in the leaves. Can you find it?

Spruce Grouse: Fool Hen of the Northern Forest

A poster child for the Northern Forest, the Spruce Grouse (Falcipennis canadensis) is one of the rarest birds in Vermont. Not only does the species depend on a relatively small patch of lowland spruce-fir forest in the Northeast Kingdom for its year-round habitat, but in winter it feeds almost exclusively on conifer needles, spending most of its time browsing among the branches.

A slightly smaller, darker cousin of the widespread Ruffed Grouse (Bonasa umbellus), Spruce Grouse are well-known for allowing humans to approach within a few feet before flying. Not only has this behavior resulted in their nickname – fool hen – but it may well have played a role in their population decline during the 19^th century when they were often taken for food. The male Spruce Grouse (pictured above) is most easily recognized by its black breast bands, finely barred gray and black feathering, and a crimson comb above each eye. The female is darker brown then the more common Ruffed Grouse, and is barred with black.

The Spruce Grouse is widely distributed across the boreal forest of Alaska and Canada. The southern edge of their range occurs where coniferous forests dip into the northern United States, in New England, New York, the northern Midwest and the Northwest. In Vermont and New York, the Spruce Grouse is listed as Endangered, with both states estimating their populations at 150 to 300 adult birds. In Vermont, the current breeding population is limited to a 25-square mile region in the Nulhegan Basin, primarily owned by the U.S. Fish and Wildlife Service and the Vermont Fish and Wildlife Department.

During the warmer months, Spruce Grouse feed on a variety of leaves, forbs, seeds, berries, and insects. As autumn turns into winter, they slowly begin shifting their diet to just conifer needles, becoming much more arboreal as the ground becomes covered in snow. During this diet shift, their gastrointestinal organs change as well. Since the birds must eat more food to maintain their mass and energy balance in winter, and conifer needles are more difficult to digest, the gizzard grows by about 75 percent, and other sections of the digestive tract increase in length by about 40 percent. In addition, to help Spruce Grouse withstand those long, cold winter nights, their crop can store up to ten percent of the bird’s body weight in food, to be digested at night when foraging opportunities are limited.

Sightings – Highlights this week consist primarily of waterfowl, including a Northern Pintail on Lake Wantastiquet in Vernon; a Canvasback drake, two Redhead drakes, and a Ring-necked Duck off the South Hero Causeway; 5 Common Loons at the Charlotte Town Beach; a flock of about 900 Canada Geese seen flying north over Rutland; 5 Mute Swans remain at the Grand Isle ferry landing along with a Red-breasted Merganser; and a rare, unconfirmed female Three-toed Woodpecker was observed up close in Berkshire.

You can explore all the birds reported last week in Vermont and add your own sightings at Vermont eBird.

Report from the Field: Dominican Republic

VCE biologists have been working in the Dominican Republic since 1994 on bird conservation and research. This year, we have a crew studying Bicknell's thrush and other birds in two regions - in the north at La Canela and in the southwest at Pueblo Viejo in Bahoruco National Park.

We just spent a week at La Canela. Loma La Canela is a part of the Reserva Científica Loma Quita Espuela in the northeastern mountains of the Dominican Republic. This range, the Cordillera Septentrional, is heavily developed for agriculture, and the reserve represents one of only two protected areas within the range. It is one of the best watered parts of the DR, receiving almost year-round precipitation from the trade winds.Daily rains hampered our work and created very muddy conditions. But, we were able to capture 5 Bicknell's thrushes and attach miniature radio transmitters on them to monitor their territories in this second growth forest. Unfortunately, one bird was killed overnight by a rat and partially eaten. Introduced rats may be a big problem for birds. We have captured 15 rats each night the entire week on our study plot.

We'll keep you updated on our work with dispatches from the field!

Chris Rimmer

Weekly Bird Notes: Mute Swan Invasion

With an eight foot wing span, an elegant long neck and white plumage, the mute swan was brought to North America from its native lands in northern and central Eurasia in the late 1800s to grace the ponds of parks and estates. Escaped individuals established breeding populations in several areas, where their aggressive behavior now threatens native wildlife. At least 14,000 mute swans now live along the U.S. Atlantic coast alone, according to the U.S. Fish and Wildlife Service.

Tundra swans and trumpeter swans are the only swans native to North America. Adult tundra and trumpeter swans have white feathers similar to mute swans, but both native species have mostly black bills. Native swans nest primarily in arctic habitats and reside in the eastern United States only during migration and winter.

Mute swans are very aggressive toward native waterfowl and they overgraze wetland vegetation. It is estimated that they eat nine million pounds of vegetation in Maryland each year. They have been found to cause terns to abandon their island nesting colonies and trample their eggs and chicks.

Relative newcomers to Vermont, mute swans have been observed annually here since 1993. They have successfully nested in at least one location and they appear to be establishing populations at other locations. According to the Vermont eBird database, most sightings come from the northern portion of Lake Champlain and the southern Connecticut River valley.

Mute swans first breed at age three. They lay five or six eggs and usually four or five cygnets survive. The life span for a wild mute swan can exceed 25 years, and with few predators, biologists expect that the population will continue to increase without proper management.

Five juvenile mute swans were reported last week at the Grand Isle ferry landing. Seven were found on Lake Wantastiquet in Vernon.

Open water on Lake Champlain provided waterfowl highlights this week. Two harlequin duck and several long-tailed ducks were found at Shelburne Point. A snow goose was seen in Shelburne Bay. A drake northern pintail was found at the Colchester Causeway. Highlights at the South Hero Causeway included 2 male redheads, 2 Barrow’s goldeneyes and a female red-breasted merganser.

Common loons were seen at the Grand Isle ferry landing, Meach Cove and eight at the Charlotte Town Beach. Nineteen bald eagles were observed at the Sandbar Causeway. Both Iceland and glaucous gulls were found at Sandbar Causeway and the Grand Isle ferry landing.

You can explore all the birds reported last week in Vermont and add your own sightings at www.ebird.org/content/vt.

Red Knots and the Crab

This Sunday, February 10, at 8pm EST, the award-winning PBS series “Nature” will feature migratory Red Knots and the horseshoe crab. Crash: A Tale of Two Species examines the amazing relationship between these two threatened species; check local listings at: http://www.pbs.org/wnet/nature/.

Recently Discovered!

Few modern animals are as deserving of the title "living fossil" as the lowly horseshoe crab. Seemingly unchanged since before the Age of Dinosaurs, these venerable sea creatures can now claim a history that reaches back almost half-a billion years. Scientists have revealed rare new horseshoe crab fossils from 445 million year-old Ordovician age rocks in central and northern Manitoba, which are about 100 million years older than any previously known forms.

Weekly Bird Notes: Pileated Woodpeckers

The largest woodpecker in Vermont is one of the most easily recognized birds in our area. Pileated Woodpeckers are similar in size to a crow and reside in Vermont year-round. Identified by their black bodies, white facial stripes extending down the sides of the neck, white underwing patches, and bright red crest, Pileateds are the culprits behind the large piles of wood chips at the base of a freshly chiseled tree.

Driving to work recently, I noticed several large rectangular holes made by a Pileated searching for ants and wood-boring beetle larvae. They pound on the tree trunk with their strong bill and listen for increased ant activity or hollow areas where insects may be hiding. They then use their long, barbed tongue with sticky saliva to extract ants from tunnels in the wood. Insects make up the bulk of their diet, supplemented by nuts and fruit when available.

Pairs are thought to mate for life. They defend their territory throughout the year with their distinctive drumming, short bursts of loud resonating drumming quicker in the beginning and end. They also use a repeated “wuk” call or whinny, similar to that of the Northern Flicker, only slower and irregular.

Found in coniferous and deciduous forests throughout southern Canada, the eastern half of the U.S., and the Pacific coast and northern Rockies, Pileateds establish territories in areas with a few scattered large, dead trees. These dead trees are used to excavate nesting cavities, and, because they are often the tallest trees in the forest, put them at increased risk from lightning strikes. Lighting strikes are a notable source of mortality for Pileateds, though predation by large raptors is the most common cause of death. On average, they select seven additional naturally hollowed out trees for roosting sites. These cavities provide protection from predators and the elements and allow them to stay warm at night. Populations of this species are limited in most areas by the presence of suitable nesting and roosting trees, a situation more prevalent in areas with heavy logging.

Pileated woodpeckers play an important role in forest communities. Abandoned nesting and roosting cavities are used by other birds, mammals, reptiles, amphibians, and invertebrates for nesting and protection. Extensively chiseled trees and logs also attract Red-bellied, Downy, and Hairy Woodpeckers and House Wrens, all of which have been observed feeding side-by-side with Pileateds.

While Pileateds were recorded on roughly half of the areas surveyed by Vermont Breeding Bird Atlas volunteers in the last 5 years, the species was once rare in the east. The widespread deforestation for farms in the late 1800s removed much of their habitat. Not until farms were abandoned and forests regenerated did their populations rebound. Since the 1950s, they have been increasing in number as evidenced by the Breeding Bird Survey, a continent-wide survey of North America’s breeding birds.

Other Sightings

Two Harleqin ducks and a Long-tailed duck were seen at Shelburne point and two redhead ducks were found at the South Hero causeway on 28^th. The day before a flock of 170 gulls included two 1st winter glaucus gulls, three 1st winter Iceland gulls, two bald eagles and about 2,000 common goldeneye were at the north end of the causeway on the receding ice edge. Five mute swans were observed off Grand Isle on the 27^th. A yellow-bellied sapsucker was found in Middlebury on the 28th. Barred owls continue to be reported throughout the state near road edges and bird feeders.

You can explore all the birds reported last week in Vermont and add your own sightings at www.ebird.org/content/vt.