Hot off the Press

...Bobolink wintering ecology paper in Ornitologia Neotropical. VINS biologist Rosalind Renfrew describes groundbreaking findings about Bobolink flock locations, behavior, habitat associations, and status as a pest species on wintering grounds in Bolivia.

Of Peter and the Mouse

If you happen to be named Peter, you might feel appreciated, and perhaps even downright popular on a spring day. In an endless mantra that serves as an advertisement for its territory, the tiny, feisty Tufted Titmouse calls out the name repeatedly.

This time of year, the smart-looking tufted titmouse is hard to miss. Not only will it occasionally announce its presence to the Peters of the world (one was heard in Milton this week), it is also drawn to feeders in the winter. Named for the elf-like gray crest on its head, it is slightly larger than a chickadee. Its orange flanks and white underside contrast beautifully with its gray back and head.

If you see the titmouse at your feeder in winter, it is likely you will be able to hear “Peter” in spring as well. Unlike many chickadees, Tufted Titmouse pairs do not join larger, migrating flocks outside of the breeding season. Instead, most remain on the territory as a pair. Frequently one of their young from that year remains with them, and occasionally other juveniles will join them. Once in a great while, a young titmouse will remain with its parents as a “helper” in raising the next year's brood.

Although not migratory, the titmouse may be seen in mixed species foraging flocks. Each species plays a different social role in these groups. The titmouse often acts as a “nucleus” species that accumulates other birds as they move, much like the dust in a rain drop. The attraction? They make a clamor in response to the presence of a predator, providing a convenient alarm system for more solitary birds. Migrating birds that are unfamiliar with the local terrain can also benefit from the information provided by these year-long residents.

In Vermont, “Peter” is ringing out in more places than ever. A bird of the eastern U.S, the Tufted Titmouse has expanded its range east and northward into New England and Canada. Reasons for the extension are unclear, and theories range from climate change to an increased food supply provided by bird feeders. Regardless of the reason for the expansion, it helps that the titmouse is a generalist species, adaptable to a variety of habitats.

Other sightings

The blizzard made for fewer bird observations in the past week, and many were feeder observations made from within cozy homes. Among the typical winter species like the titmouse were 14 Tree Sparrows at a feeder in Jericho Center, and Cooper’s and Sharp-shinned Hawks stalking feeders. Some birders are still venturing outside; a Belted Kingfisher was observed during a snowshoe in Rutland, as well as 75 Snow Buntings. A walk in Brattleboro’s Retreat Meadows produced a Northern Mockingbird and Northern Shrike.

- Rosalind Renfrew

Lynx Found in Northeast Kingdom

The big cat isn't a catamount -- a species that is believed to have vanished from the state's landscape in 1881 -- but rather a Canada lynx, a close relative of the bobcat that was last recorded in Vermont in 1968.

Biologists from Vermont and New Hampshire haven't seen the lynx but have concluded the cat is here after seeing a track in the snow Feb. 7.

The lynx track was observed by New Hampshire biologist Will Staats, who was hunting bobcats in the 4,970-acre Victory Basin Wildlife Management Area. He called Paul Hamelin, a wildlife biologist in the St. Johnsbury office of the Vermont Fish and Wildlife Department, and both men confirmed the identity of the lynx tracks.

The two were able to observe where the lynx had traveled near a set of bobcat tracks, making it possible to take photos of the two sets of tracks. The lynx tracks are noticeably larger and spaced farther apart and have other unique identifying features.

"It just jumped right out at me," said Staats, who has tracked two separate lynx in New Hampshire, both close to the Connecticut River. "If you've got good snow conditions and you've been tracking animals as long as I have, it's pretty much unmistakable."

Kim Royar, Vermont's furbearer biologist, said historic accounts of Canada lynx in Vermont suggest that they were never as numerous as bobcats, and most likely were transitory animals that wandered in from northern Maine, New Hampshire or Canada. Lynx numbers rapidly declined in Vermont by the mid-1800s, when about 75 percent of the state's forest had been cleared for farming.

It's likely, Royar said, that the latest lynx is just visiting Vermont, likely looking for snowshoe hares, the cat's preferred prey.

Staats said he wasn't surprised to see a lynx track in Victory Basin.

"The habitat is good for them there," Staats said. "We've got plenty of snowshoe hare; there's a good amount of lynx in western Maine; and they have the ability to travel long, long distances."

Vermont Fish and Wildlife, Royar said, has had sightings of lynx in the past from around the Northeast Kingdom, but the department had not been able to confirm a track or sample scat left by the animal in question.

Looking very similar to bobcats, Canada lynx have ear tufts and ruffs on their cheeks larger than those of bobcats. Lynx have longer legs and larger, more-heavily furred feet than bobcats, which enable them to travel easily on snow.

Hamelin and Staats did find a stray hair near the track, Royar said, which is being tested to determine the species of animal it came from.

Protected by state and federal laws, the lynx also is listed as a furbearer species in Vermont. It is federally listed as a threatened species and listed by Vermont as endangered. Federal law provides a six-month jail sentence and $25,000 fine for killing one.

Staats said he's ventured back into the area since Feb. 7, but has been unable to find evidence of the cat.

"It could be in Canaan, western Maine or northern New Hampshire by now," Staats said.

Owl Love

"Who-hoo-ho-oo" might not sound like much to most people, but the hoot of the Great Horned Owl means love is in the air. Valentine's Day signals that spring is on its way, with birds like the Great Horned Owl, Bald Eagle, Red-tailed Hawk, Common Raven, American Crow and Gray Jay starting to pair up and prepare for another breeding season.

Great Horned Owls have the distinction of being the earliest regular breeding bird in Vermont, with some pairs already sitting on eggs. They usually use old stick nests of crows, herons, and hawks, but also nest in cavities, on cliffs, in deserted buildings, and on the ground.

Most people think of owls as living deep in the forest, but Great Horneds prefer to nest near forest edges for hunting. They hunt from perches at night and are opportunistic feeders, meaning that they prey on whatever they happen to come across. Great Horneds have the most diverse diet of any owl in North America with top prey items being rabbits, mice, and waterfowl. It is the only animal that regularly preys on skunks.

The most widespread of all North American owls, Great Horneds occur across the entire continent except for northern Canada and southeastern Mexico. Within this range, they inhabit everything from tundra and forest to grassland and desert conditions, and can even be found in suburbia. They are found throughout Vermont, but are more common in the Champlain Valley and in the southern part of the state.

Great Horneds are perhaps the longest-lived owl on the continent, with one individual known to be at least 28 years old. They are the only large (46-63 cm in length), heavy (1-2.5 kg) owl with ear tufts. The familiar Barred Owl weighs in at only 0.5-1 kg and is 43-50 cm long. As is typical for raptors, the female is larger than the male; however, the male maintains a deeper voice. If you are lucky enough to hear a pair duetting this time of year, you can easily tell them apart by voice.

Other sightings

Birdwatching highlights this week include several birds not normally found in Vermont at this time of year: a lingering Eastern Towhee at a feeder in Winhall, two Gadwalls and a Hermit Thrush at Button Bay in Panton on Feb. 11, a Yellow-rumped Warbler in Woodstock on Feb. 10, an Eastern Phoebe in Brattleboro on Feb. 9, and an immature Red-shouldered Hawk wintering in Westminster.

This winter's first report of a Bohemian Waxwing, the northern cousin to the common Cedar Waxwing, came from Burlington last week. A Merlin, the smaller relative of the Peregrine Falcon, has been spotted at the north end of Lake Bomoseen the last two weeks. An uncommon Iceland Gull was observed off Grand Isle on Feb. 10.

-Julie Hart

El Niño: turning back the Bobolink clock?

A report just came in about yet another town flooded here in Bolivia. This time it’s Cochabamba, a city on the edge of the Andes, in the middle of the country. For the past month, El Niño flooding has hit nearly every part of the country, inundating towns, destroying roads and bridges, and ruining most of the country’s agricultural production.

With most rice fields destroyed by the flooding, the Bobolink’s major food source here during the non-breeding season has been relatively scarce. Flocks appear to be more dispersed, and roosts and foraging flocks that we have found have been smaller than last year. Most roads are impassable, and our attempts to monitor and capture the birds have been largely unsuccessful. For over a month my colleague Ana Maria and I have traveled hundreds of miles to regions where we have found Bobolinks in past years, only to find that we cannot complete the last leg of the trip to reach our sites. In the best of circumstances, we can only watch airborne flocks disappear into the distant sky, headed for their roosts or foraging areas.

Ana Maria and I don't feel sorry for ourselves. For the last four weeks we have been passing by makeshift roadside tents that serve as temporary homes for some 40,000 families. Their houses are flooded to the roof. The children play in the contaminated water. In one town truckers provided their rigs as homes for people – they might as well, as there is no food to transport. Even here in the relatively modern city of Santa Cruz, there have been recent outbreaks of Denge and Cholera, and hospitals are strained with too many patients.

Despite its wealth of natural resources like forests and natural gas, Bolivia is one of the poorest countries in Latin America, struggling politically, culturally, and economically. Perhaps this grim fact is behind the amazingly resilient nature of people here. One farmer told me, after losing his entire crop for the year, “Nothing is ever certain here.” It was his smile as he said it that impressed me as truly Bolivian. Unlike in our country, here in Bolivia there is no such thing as emergency relief or government subsidies for farmers.

In the meantime, the Bobolinks have likely redirected their attention towards the water-logged grasslands of Bolivia’s eastern lowlands. Not yet penetrated by modern agriculture, these wetlands are part of a landscape mosaic that is rich in biodiversity. Before agricultural expansion in central South America, the Bobolink was once a bird of the expansive pampas grasslands, and only in recent decades have they been allured by the bounty of agricultural crops. Perhaps El Niño is returning them to old traditions.

Rosalind Renfrew
Conservation Biologist

Vermont Weekly Bird Notes 2/9/07

Bird song is noticeably absent on winter mornings in Vermont. But, some are hearing a new bird tune in their yards, a fast "tea-kettle, tea-kettle, tea-kettle". A flatlander has made its way north to live in Vermont, the Carolina wren.

Carolina wrens sing year round to lay claim to their territory. Winter singing is food dependent and is not common during abnormally cold and snowy weather. Unlike other wren species, only the male sings the loud song. One captive male Carolina wren sang nearly 3,000 times in a single day!

They were first found nesting in Arlington, Vermont in 1978 during the first Vermont Breeding Bird Atlas. Nearly 30 years later, the second atlas has found them in nearly every part of the state. Why the sudden change in this wren’s range?

The Carolina Wren is sensitive to cold weather, with the northern populations crashing after severe winters. The gradually increasing winter temperatures over the last century may have been responsible for the northward range expansion into Vermont. A cold winter can have devastating effects on them, but with warmer winters they often recover within a few years.

Areas where the average minimum January temperature drops below 10° F are not suitable for Carolina wrens. They just can’t hack a good old fashioned New England winter. But, that gripping cold and deep snow is beginning to be a thing of the past. Burlington has seen only three Januarys since 2000 below that threshold. Severe winters are now infrequent enough to allow for wren populations to expand and move northward.

For example, several mild winters prior to 2003 allowed Carolina wrens to expand and increase northward. However, January and February 2003 were winter-as-usual with frigid temperatures that knocked back Carolina wren populations. They were able to rebound beginning with the mild winter last year. This winter began mild, but the arctic air has returned now. Sharing your observations on Vermont eBird will help us further understand their population changes.

Wrens are probably sensitive to severe winter conditions because their food is covered by snow and ice for extended periods, leading to starvation. They are not fond of seeds from your bird feeder, but they will occasionally come to a suet feeder as a supplement during extreme winter weather. The proliferation of bird feeders may have also helped the wrens move northward.

Carolina wrens were seen this week in Burlington, East Dorset, Middlebury, Randolph, Shelburne Point, and Woodstock.

A male three-towed woodpecker, a female black-backed woodpecker and many displaying white-winged crossbills were observed at Moose Bog on February 3 Two crossbills were also spotted on Grand Isle on February 2.

A northern flicker was observed in Shelburne on the 4th. Red-bellied woodpeckers were seen in Charlotte, Bridport, and Pownal.

Snow buntings were seen in numerous large fields. A flock of 200 were found in Danby Four Corners on February 1.

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

Kent McFarland

Vermont Weekly Bird Notes 2/2/07

Upside-down Birds

Nuthatches are common birds with uncommon habits. They are the only bird that walks upside-down. And almost everyone can watch this feat in their own back yard.

Nuthatches explore all surfaces of trees -- top, sides and bottom -- searching for seeds and insects. Many of us marvel at their ability to walk down trees -- head first. Why don't they fall? Perching birds characteristically have four toes, three that face forward and one that faces backward. The backward facing toe is akin to our thumb and is called the hallux. Nuthatches have a stronger hallux than most perching birds their size and they use it to grasp the tree at a right angle to the trunk. In addition, they always have at least one foot tightly grasping the tree and keep their feet spaced far apart.

Nuthatches are named for their behavior of wedging a nut into a tight cranny and then pecking at it until it is cracked. Originally called "nuthacking," the name morphed into its present form. To accommodate this behavior, they have developed a stout bill (for pounding) that comes to a point (for probing).

There are two species of nuthatches in Vermont, the White-breasted and Red-breasted. White-breasteds have a white breast as their name suggests and a black crown with white cheeks. Red-breasteds have a rusty colored breast and a black stripe through the eye.

Another important distinction between the species is habitat preference. White-breasteds live year-round in deciduous forests, while Red-breasteds prefer conifer dominated forests. The boreal forest supports 25 percent of the breeding Red-breasted population. This preference for conifer forests leads to an interesting phenomenon called irruption. Roughly every other year the boreal seed crop is low and Red-breasteds migrate south in search of food.

Because winter is such a hard time of year to find food, nuthatches hide seeds and insects in nooks and crannies for later consumption. Instead of finding a few good places to hide masses of food like squirrels and some woodpeckers, they hide just one food item per cache.

Bird feeding is known to help nuthatches maintain their health over the cold winter months, and fortunately for us, both species are common feeder birds in Vermont. They favor suet feeders and sunflower and safflower seeds.

Other sightings

White-winged Crossbills, another irruptive species taking advantage of the heavy cone crop this winter, were confirmed breeding at Moose bog in the Northeast Kingdom last week. Black-backed and Three-toed woodpeckers, Gray Jays, and Boreal Chickadees continue to delight birders in the bog making for an exciting day trip.

Shelburne continues to be a good spot for waterfowl, with the highlights being two Harlequin Ducks, a pair of Lesser Scaup, Hooded Merganser and rafts of goldeneye.

-Julie Hart