The Bobolink Project

Banded Bobolink photo by Marc Faucher

The Bobolink population is in decline. By one estimate half of the Bobolink population has disappeared since 1970. In Vermont the most recent Breeding Bird Atlas recorded a modest 6% decrease in block occupancy between the first and second atlases. Breeding bird survey data in Vermont revealed an annual decrease of of 2.1% between 1982 and 2007. Thus, Bobolinks are listed as a species of special conservation concern in Vermont.

The explanations for this decline are multifactorial, but loss of habitat is a major factor. As Vermont's grasslands have reverted to mature forest or succumbed to development, suitable nesting conditions for Bobolinks have disappeared. More recently, intensification of agricultural practices, specifically hay mowing during the breeding season, has devastated Bobolink reproduction success. Studies by Allan Strong from UVM and Noah Perlut now at the University of New England demonstrated that fields cut in mid-June resulted in virtually 100% mortality among fledglings. Delayed mowing resulted in improved survival of fledged chicks.

Enter the Bobolink Project. Organized by Allan Strong at UVM and colleagues at Mass Audubon, Connecticut Audubon, and the University of Connecticut, the Bobolink Project solicits private donations the proceeds of which are distributed to farmers willing to delay hay cutting until after the breeding season in June and July. In a process known as a reverse auction farmers submit bids to compensate them for the loss of value for hay that is harvested late in the growing season. Since its inception in 2013 the Bobolink Project has raised over $150,000.

This project has been a resounding success. In 2017, for example, over 600 acres of prime grasslands in Vermont were protected. An estimated 229 breeding pairs occupied this territory, producing 639 chicks that otherwise might have been sacrificed to the blade. Overall in 2018 the project was able to fund two-thirds of the applications that were received, which protected 932 acres of grassland habitat on 20 farms (16 farms in Vermont). It is estimated that 368 pairs of Bobolinks were protected and that over 1000 Bobolink chicks fledged as a result. For the past two years Audubon Vermont has assumed administrative responsibility for this project in Vermont, while Strong and his colleagues continue to refine the process of protecting habitat while encouraging farmers to enroll in the program.

Bobolink fall migration (red=male; white=female). Perlut,The Auk, Oct. 2018

Bobolink survival and dispersal are at the heart of Noah Perlut's long-term interest in protecting grassland birds. Starting as a graduate student at UVM 17 years ago, Noah has banded over 7000 Bobolinks and Savannah Sparrows at Shelburne Farms, then attempted to recapture them when they returned from their wintering grounds in South America. More recently he and his team of enthusiastic students have placed geolocators on some of these birds to identify their migration pattern and their wintering location in South America. Amazingly, these studies have documented that these small birds make a 6000 km journey from Vermont to South America and back every year, generally returning to within 1500 meters of their natal site in Vermont. The map on the right illustrates the migration of 13 Bobolinks sporting geolocators that Noah had placed on their backs in Vermont. Later these birds were recaptured and the data were analyzed. Many of these Bobolinks took the transoceanic route, flying non-stop hundreds of miles over open ocean to reach their final destination.

Noah has presented the results of his continuing work in programs at Shelburne Farms and for the GMAS. His stories of Bobolink survival document the travels of the children, grandchildren, and great-grandchildren of the birds that he originally banded in Shelburne. For the past few years the GMAS has been pleased to participate in this work, surveying fields in Shelburne and Charlotte searching for banded birds, which Noah and his team later recapture.

What about Bobolinks on their wintering grounds? The research group at the Vermont Center for Ecostudies has promoted the concept of "full life cycle conservation", emphasizing the importance of protecting birds on their wintering grounds and migration stopovers as well as at their breeding sites. Roz Renfrew from VCE has focused her studies on Bobolinks in Bolivia, Argentina, and elsewhere in South America (see previous HT blog entry, 4/29/2011). Here rice farmers regard Bobolinks as pests (the Latin name for Bobolinks Dolichonyx oryzivorous means long-clawed rice eater after all) and use active methods, including shooting them, to drive them from their fields. Once again balancing the needs of farmers with those of the birds is the key to successful conservation efforts.

Bobolink populations are in decline, true, but sustained efforts in Vermont by conservation biologists at UVM, VCE, Audubon Vermont, and the University of New England have successfully mitigated some of the factors leading to this decline. Currently, the Bobolink population is estimated at 8 million birds. Thus, the mantra "Keep common birds common" is especially applicable to the plight of the Bobolink.

Christmas Bird Count 2017 Summary

The GMAS completed another successful CBC on Sunday, December 17, 2017 under the able leadership of Shirley Johnson. This was Shirley's twentieth year organizing this event-a record in itself-and the 70th CBC conducted in the Burlington circle.

Red-bellied Woodpecker

Photo by Marc Faucher

We were not disappointed. The weather was acceptable by CBC standards and birds were plentiful, though somewhat lower than recent years. We counted 17,516 birds (the 2014 record was 24,306) and recorded 70 species. During count week three additional species were added to our count-Snowy Owl, Northern Mockingbird, and Red-winged Blackbird. Woodpeckers were especially common this year. Twenty-eight Red-bellied Woodpeckers were counted, more than double our previous record. Also, ten Northern Flickers represented a new record for our count. Likewise, 835 Dark-eyed Juncos and 26 White-throated Sparrows smashed previous records for our circle.  Individual observations of note included a Golden Eagle seen at Macrae Park, a Yellow-bellied Sapsucker present at a feeder, and two Turkey Vultures, an unusual species at this time of year. 

On the downside, there were no irruptive species reported in our count this year. In general, the number of duck and goose species recorded was lower than usual, possibly due to mild weather preceding the count. In fact, there were no Wood Ducks, Northern Pintails, or American Wigeon reported this year and significantly lower numbers of Snow Geese, Canada Geese,  Mallards, Black Ducks, and Common and Hooded Mergansers were counted. Only Greater and Lesser Scaup and Common Goldeneyes were frequent, though well below record-breaking numbers.

Among the songbirds Black-capped Chickadees, while common (642) were far from our record set in 2006 of 1072, an observation in keeping with state-wide findings in the VT eBird database. Likewise, Red-breasted Nuthatch numbers were very low (14), especially when compared to our record of 95 set in 1997.

This year we had 14 teams plus feeder and Crow counters consisting of 63 participants. Fifty years ago in 1967 only 6 observers participated in the CBC. In 1967 this small group reported 3528 birds and 42 species. We have grown over the years, but the enthusiasm for birds never wanes. Already we are looking forward to the 71st Burlington circle CBC in 2018. Hope to see you there.

Lyme Disease in Vermont: An Occupational Hazard for Birders

November 1 was a warm, sunny day in Vermont a few seasons ago. As I walked out of the woods at the LaPlatte River Natural Area in Shelburne, I looked down at my pant legs and saw them-ticks-a dozen or more on each leg. As I brushed the tenacious ticks away I thought,  “Vermont-we’ve got a problem”. Lyme disease is the most common tick-borne disease in the country, accounting for over 30,000 new cases each year. In recent years Lyme disease cases in Vermont have skyrocketed. In 2013 nearly 900 probable or confirmed cases were reported to the Vermont Department of Health, placing Vermont first in the country in terms of the incidence of this disorder. Other states with a high incidence of Lyme disease included Maine and New Hampshire. What is going on here?

In North America Lyme disease is caused by a spirochete called Borrelia burgdorferi. This microorganism is transmitted by the bite of black-legged ticks (Ixodes scapularis), formerly known as deer ticks. These ticks are commonplace in our forests and are increasing, due in part to reforestation of the landscape and perhaps the effect of climate change. But this is not the whole story. Ixodes ticks have a complicated life cycle. These ticks do not live forever, thank God. Rather, they live for two years during which they undergo three successive molts, that is transformation to a larger size and different form.  After hatching from an egg these stages of development are called larva, nymph, and adult. At each one of these stages the tick must ingest a blood meal from an appropriate host or else it dies. Many hosts can serve as blood donors-mice, chipmunks, deer, even birds, especially birds that nest or forage on the ground like sparrows, robins, thrushes, and ovenbirds.  Once the ticks ingest a blood meal they drop off the host, hide in the leaf litter while they undergo a molt to the next stage of development, and lurk in the brush waiting to attach like a burr to their next victim. Ultimately, adult male and female ticks meet on a host and reproduce. White-tailed deer appear to be the preferred host for adult ticks. At this point the pregnant female, after ingesting a third blood meal, drops off the host and lays her eggs on the ground.

If the ticks are infected with B. burgdorferi they can transmit this spirochete to their blood donors. However, not all of their hosts are “competent” to serve as a reservoir for this infection in nature. To qualify as a reservoir three conditions must be met-availability, poor grooming behavior, and an ability to tolerate chronic infection with B. burgdorferi. The mammals that best fit these qualifications are white-footed mice, chipmunks, and shrews. White-footed mice, in particular, are the most abundant and competent reservoir host. 

Interestingly enough, black-legged tick larvae are not infected at birth. Rather, they acquire Borrelia from a reservoir host during their first blood meal. Subsequently, the ticks are infected for life and can pass this infection on to other animals and to you. However, many animals, including deer, clear the infection rapidly and do not pass the spirochete on to ticks or to other creatures. Birds carry ticks, too, but efficiently remove them and kill them with their bills during the process of grooming. Birds also recover quickly from Borrelia burgdorferi infection and do not transmit the organism to other animals. Thus, sustaining Borrelia infections in nature involves a complicated process in which the infected reservoir population, and therefore the density of infected ticks, is regulated by the availability of food, the presence or absence of predators and competitors for that food, and the diversity and number of available hosts for black-legged ticks, only some of which serve as a reservoir for B. burgdorferi.

So what about you? If you are a Vermont birder who spends time in the woods you are at significant risk of acquiring Lyme disease from a tick bite.  As soon as you enter the woods you intersect with the life cycle of the black-legged tick. That is, you have entered their environment. Both nymph and adult black-legged ticks are capable of transmitting B. burgdorferi to you, but the nymphs are more problematic because they are tiny and their bite may not be recognized. Adult ticks, in contrast, are larger and are often removed before they have attached and fed. The first nymphs appear in the spring, when the temperature exceeds 40 degrees F. Nymphs that have fed successfully drop off of their hosts and develop in the leaf litter into adults. The population of adult ticks peaks in the fall. Hence, the ticks that I found on my pant legs in November were adult black-legged ticks. 

How likely is it that a nymph or adult black-legged tick in Vermont is, in fact, infected with B. burdorferi? The short answer is “very”. First, according to tick surveys conducted by the Vermont Department of Health, black-legged ticks are the most common ticks found in Vermont, accounting for over 75% of the ticks submitted for identification, although American dog ticks and Lone Star ticks were identified in the survey, as well. In 2013 Alan Geise from Lyndon State and Erica Berl from the Vermont Department of Health conducted a survey of ticks obtained from 12 sites in Vermont-six in the eastern part of the state and six in the western part. Both northern and southern counties were represented in this study. With the exception of the northeastern corner of the state infected ticks were discovered in every county studied. In aggregate 27% of the captured nymphs were infected with B. burgdorferi as were 62% of the adults. These percentages tended to be higher in the southern and western counties in Vermont. Once you know that the percentage of infected ticks is high, though, the exact number becomes less important, since the density of infected ticks in specific habitats varies tremendously even within a given county. Smaller forest fragments with abundant understory and leaf litter and fewer predators and competitors tend to support larger populations of white-footed mice and a higher density of infected ticks. So be careful out there!

So what to do to prevent Lyme disease assuming that you are unwilling to stay out of the woods? The Vermont Department of Health makes wise recommendations for prevention encapsulated in the slogan “Repel-Inspect-Remove”. Wear light clothing to more easily recognize attached ticks. Tuck your pant legs into your socks. Spray Permethrin, an acaricide, onto your clothes. Apply 25%-30% DEET to your exposed skin. Shortly after returning from your walk in the woods check your entire body for ticks in front of a mirror. Shower within a few hours of returning home to wash off unattached ticks that you may have missed and to remove DEET. You can even toss your clothes into the dryer for an hour at high heat. Dry heat kills ticks. Each of these measures contributes independently to the success of prevention, so the more methods you use, the greater the likelihood of success.

If you do find a tick attached to your skin remove it with tweezers by grasping its mouth parts at the level of the skin and lifting steadily. Don’t bend, fold, or mutilate the tick if you can avoid it. Wash the wound with soap and water to avoid secondary infection. Black-legged ticks must be attached to your skin for at least 24-36 hours before infection with B.burgdorferi is transmitted to you. The reason for this time lag is that the spirochete resides in the mid-gut of the tick and is tethered to the cells lining the gut. Once the tick begins to ingest blood, though, the organism undergoes a reorganization of the surface proteins responsible for adherence, releases its grip on the lining cells, and migrates into the tick's circulation, ultimately appearing in the saliva. It is tick saliva that transmits the organism to you.

A newly-attached tick often stimulates a local inflammatory response in the skin surrounding the attachment site. This is not a sign of Lyme disease. Also, during feeding ticks become engorged with blood and increase significantly in size. At this point after removing the tick, a single dose of an antibiotic such as doxycycline given within 72 hours is often effective in preventing Lyme disease. Consult your primary care physician for advice. Don’t forget your pets. Dogs and other domestic animals can get Lyme disease and can bring ticks into the house from outside. Check your pets for ticks as well as yourself.

What if, despite all of your efforts at prevention, you develop Lyme disease? Lyme disease peaks in June, July, and August, mirroring the appearance of tick nymphs, and evolves through several stages-early manifestations, early disseminated disease, and late complications. Over 70% of Lyme disease patients develop a characteristic skin rash expanding from the site of the tick bite called erythema migrans. This rash occurs 3-30 days after the tick bite and may or may not have a characteristic “bulls-eye” appearance. This rash may be accompanied by constitutional symptoms such as fever, muscle pain, and fatigue.  A few weeks later other symptoms may develop such as a disseminated skin rash, stiff neck, headache, facial weakness (Bell’s palsy), or even cardiac symptoms such as palpitations. Weeks or months later asymmetrical arthritis occurs in about 30% of untreated patients, manifested by swelling of a large joint, typically one of the knees, with or without pain. Subtle cognitive disabilities may be present, as well. If the diagnosis of Lyme disease is established antibiotics can be effective in killing the spirochete. The earlier in the course of the disease that treatment is started the better.

A few other diseases are transmitted by black-legged ticks, although currently these diseases are rare or uncommon in Vermont. Anaplasmosis, a rickettsial disease manifested by flu-like symptoms and depression of white blood cells and platelets in the circulation, has been reported in Vermont mainly in Bennington and Rutland counties. Anaplasmosis responds to antibiotic therapy, but can cause severe illness if left untreated and occasionally can be fatal. The number of cases of Anaplsmosis reported in Vermont, while less than 100 cases per year, has been rising steadily.

Babesiosis is a parasitic disease like malaria and, like malaria, can cause severe hemolytic anemia. Babesiosis is transmitted by black-legged ticks. Only a single reported case of babesiosis that was acquired in the state (that is, not acquired by travel to other parts of the country where babesiosis is endemic) has been confirmed in Vermont.

Finally, Powassan-type virus infection can be transmitted by Ixodes ticks. This virus causes encephalitis that resembles West Nile virus infection. Only one case of Powassan virus infection has been confirmed in Vermont in 1999.

In conclusion Lyme disease is a multisystemic inflammatory disorder and is the most common tick-borne disease in the country. The incidence of Lyme disease has increased dramatically in Vermont, New Hampshire, and Maine during the past decade. Awareness of the risk of tick-borne diseases in Vermont is essential for individuals who spend a great deal of time outdoors. The risk of acquiring Lyme disease is best understood in the context of the life cycle of the black-legged tick and how you and your pets intersect with this life cycle.  Effective means of preventing Lyme disease are available and should be used. Remember Repel-Inspect-Remove and be careful.

For further information visit the Vermont Department of Health website at http://healthvermont.gov and the CDC website at http://cdc.gov and search for Lyme disease. Here is a link to my 2015 presentation about Lyme disease in Vermont and its prevention.

Lyme Disease in Vermont Presentation by Bruce MacPherson (PDF)

A Lost Loon and a Roadside Rescue

Everybody loves loons. Listening to their yodeling call on a summer evening at a remote northern lake is truly a memorable experience. Since the Common Loon was removed from the Vermont Endangered Species List in 2005, the loon population has steadily expanded and breeding success has improved. In 2015 Vermont's loons enjoyed their best breeding season ever with 87 breeding pairs producing 67 chicks.

But every chick counts. This idea was on her mind in August when GMAS Board member, Ali Wagner, came upon a lost loon chick cowering at the edge of busy route 105 in the Northeast Kingdom just east of Island Pond. How the chick found its way to this spot was a mystery. Regardless, it was in a precarious situation and Ali promptly went into rescue mode. Her companion, Tom Berriman, longtime NEK Audubon Board member, drove to the Silvio Conte NWR to access the VINS hotline, obtain permission to move the chick, and contact Eric Hanson, the conservation biologist at the Vermont Center for Ecostudies who spearheads VCE's Loon Recovery Project, while Ali tended the chick.

Coached by Eric Hynes on the phone, Ali carefully wrapped the loon chick in a towel to protect its wings and legs. Later she and Tom transported the chick to nearby Spectacle Pond and released it. The chick swam toward two adult loons on the pond, but all was not well. Loons are notoriously territorial and this couple had their own chick to worry about. Later that day the rejected chick, affectionately named Little Guy, was found hiding in the reeds by Eric Hanson, who had appeared on the scene to check out the situation. Eric scooped up the chick and headed for shore. Rescued again!

After another unsuccessful attempt to release the chick at a different location, Eric decided to take the bird to his home for a minnow dinner. The next day he transported the chick to a rehabilitation facility in Maine. Amazingly, this fortunate bird thrived in rehab and six weeks later it was released to the wild. This loon should be renamed. Instead of Little Guy, perhaps we should call this loon Lucky Guy.

Ali wrote a wonderful story about this rescue, which appears on the Vermont Center for Ecostudies blog at http:vtecostudies.org/blog/. To read this story and the later updates go to the VCE blog and scroll down to the entries for August 25, August 31, and October 13.

On Tuesday, December 8, Eric Hanson joined the members of the GMAS at the Richmond Free Library to present a program entitled The Natural (and Unnatural) History of the Common Loon. We  heard more details about this rescue from Eric and Ali and learned more about the Common Loon Recovery Project in Vermont and how we can become involved.