Shorebirds on the Move

Birds are migrating southward already? Unfortunately for you summer lovers, yes. Adult shorebirds, a diverse group that includes sandpipers and plovers, are headed southward from their arctic breeding grounds - the first sign of our waning summer.

Adults arrive in Vermont from July through August with juveniles follow from mid-August through September. The shorebirds stop at specific staging areas, like Dead Creek Wildlife Management Area in Addison, to refuel along their migratory routes from Canadian arctic breeding grounds to South American wintering areas.

The growing awareness of threats to shorebird populations and their habitats has prompted the development of international cooperative conservation networks. One such initiative that has emerged is the Western Hemisphere Shorebird Reserve Network (WHSRN). This program resulted directly from internationally coordinated research programs that showed that shorebirds use a restricted set of sites during their annual migrations and that these sites support a high percentage of their populations. These special places, which provide an exceptional abundance of food at the right time of the year, effectively form the links in a chain of sites that enables the birds to complete their migrations.

For shorebirds to survive, all the links in the chain need to be preserved, since removal of one link would disrupt the entire migration system and prevent the birds from completing their annual travels. There are currently over 30 WHSRN reserves protecting shorebird habitat from Alaska to Tierra del Fuego.

The Vermont shorebird show began in earnest last week with five species stopping in the Green Mountain state. On July 18th at Herrick’s Cove in Rockingham birders reported 30 greater yellowlegs, over 300 least sandpipers, and 22 short-billed dowitchers. On July 22nd Dead Creek WMA had a greater yellowlegs, two solitary sandpipers, four semipalmated sandpipers, and eight least sandpipers.

Other highlights this week included a little blue heron at the Hogle Wildlife Sanctuary in Brattleboro and at Brattleboro Retreat Meadows on July 20. A glossy ibis was observed from 17 -19 July at Allen Brothers Marsh in Westminster. Two sandhill cranes were spotted along Quaker Village Road in Weybridge on July 14th. On July 20 a yellow-billed cuckoo was observed in Chittenden and three grasshopper sparrows were found at the Franklin County State Airport.

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

The Reed-Straddler

Immature Least Bittern by crookrw

If American Bitterns are nicknamed thunder-pumpers, I think Least Bitterns should be called reed-straddlers. On the rare occasion that this marsh bird is seen, it is hovering above water with legs splayed clinging to the cattails.

American Bitterns are the lanky birds with striped chests you hear giving their “oong-ka-choonk”, or thunder-pumping, call in marshes. Least Bitterns occupy the same wetlands but are not as well known partly because they are smaller, as their name suggests, but also because they stay deep in the dense wetland vegetation and are not as vocally distinct (their call is usually rendered as simply “tut-tut-tut”).

Least Bitterns only measure about 30cm tall, about half as tall as an American, and are only one-fifth the weight. They are extremely well-camouflaged for their reedy haunts with a dark back, orange and white striped chest, long yellow bill and eyes, long green and yellow legs, and a white streak running from their shoulders onto their back. When threatened, they freeze in place like an American Bittern with their head and bill up, and will sometimes sway back and forth to resemble wind-blown reeds or grass.

Their compact body allows them to move easily through dense marsh vegetation in search of food or to escape predation. Their small size allows them to straddle reeds, clinging to branches and emergent vegetation aided by their short toes and long, curved claws. This allows them to search for small fish, dragonflies, and other small aquatic insects in water over its head! Their light weight also allows them to walk on lily pads and other floating vegetation where larger birds would sink.

While both bitterns occupy the same marshy habitats throughout eastern North America, they have learned to coexist. They forage in different microhabitats, with Americans foraging in the shallow peripheries and leasts in the deeper water. This also means they consume different prey with American Bittern eating insects, amphibians, crustaceans, and slightly larger fish than the least. The Least Bittern also limits its northern summers, arriving in Vermont in May and leaving by the end of August. American Bitterns take their time; they arrive April and don’t leave until October.

Two Least Bitterns were reported from Vernon in southern Vermont on July 7. Three more individuals were discovered in the cattail marshes across the river in Hinsdale, NH. All sightings were made by one observer targeting surveys for this species.

Other Sightings

Early northern nesters are beginning their fall migration with Greater Yellowlegs and Killdeer seen in Charlotte on July 13, Bonaparte’s Gull in Grand Isle on July 12, and a Tennessee Warbler in Barnet on July 11. A dozen Grasshopper Sparrows were observed on July 14 at the Franklin County Airport along with other grassland denizens like Savannah Sparrow, Vesper Sparrow, and Horned Lark.

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

-Julie Hart

Bird Espionage

Black-billed Cuckoo chicks (S. Elliott)

Every ten years the U.S. government carries out a census to collect information about the human population, including how many of us exist. Getting a handle on bird populations requires more finesse, but it is well worth the effort. Learning whether bird populations are on the rise or fall is absolutely necessary in order to use conservation dollars effectively.

A “breeding bird atlas” is a bird census that is carried out every 25 years. Begun by British botanists, “atlasing” was later adopted for birds, and most recently has been used for other taxa such as amphibians and butterflies. About 30 states in the U.S. have carried out a bird atlas, and several have started their second round after a 25-year hiatus. In 1985, the Vermont Institute of Natural Science (VINS) published the first breeding bird atlas results in the U.S.

An atlas provides a “snapshot” of the status of the birds. For five years, volunteer birders document the species that breed throughout a state. Documenting breeding evidence requires a form of espionage. Birders have to patiently and persistently watch the same birds, sometimes for hours. The results of these valiant efforts are used to produce maps depicting the distribution of every species that breeds in the state. In addition to documenting whether a species is present in an area, some atlases also count individuals of each species, providing information on species’ abundance.

Vermont is now in the final throes of data collection for its second atlas. The first 2-3 weeks in July present the final opportunity for birders to document breeding, before most birds have fledged their young. Right now Vermont birds are steeped in the thick of breeding season, with many young already taking flight and many adults in the midst of their second nest cycle (many species nest more than once in a summer, especially if their first nest fails). Some of the more rare species recently documented breeding in the state include Ring-necked Duck, Boreal Chickadee, Red Crossbill, White-winged Crossbill, Cerulean Warbler, and Tennessee Warbler.

In other birding news this week, VINS's Vermont Loon Recovery Project issued its 2007 interim update on the status of the Common Loons breeding in Vermont. To date, 54 nests have been confirmed this year, 6 of which are in new locations or on new lakes. There are currently 32 chicks swimming on our lakes and ponds, with more to come. A Bobwhite Quail was seen in Jericho Center this week. Sightings of this species are always assumed to be escapees from breeders (for example, hunting clubs), as wild populations are not believed to exist in the Northeast.

Loon Blog

Vermont Loon Recovery Project Update: July 1, 2007

As of July 1, there were 54 loon nests confirmed in Vermont including 6
new nests on Green River Res. SE, Pensioner P., Shadow L. (Concord),
Woodbury L., and one other. This number will go up as several nests not
being checked until early to mid July. There were 58 confirmed nests in
2006 and 53 in 2005. Several pairs might have gone on this past week.
The Shadow Lake pair failed after an attempt to move the nest from
someone's beach front to a nesting raft. The loons made the move to the
raft successfully but did not follow it down the shoreline 200 feet. The
pair will be back next year to try again. Woodbury Lake has its first
loon chick since the loon program began in 1978. To date, 32 chicks are
swimming on our lakes and ponds. 8 nest failures confirmed - most eggs
disappeared (predators?). On Chittenden, the raft broke loose and the
pair abandoned. I got the raft back in place asap and the pair has since
re-nested. 3 cables broke. New pair activity on Derby Pond and Lake
Dunmore (nest searching/courting). We put 8 signs around the island on
Dunmore. This lake is crazy with boats and people love the island, thus
this will be a year of education. Let's hope the pair returns in 2008.
As of last week the pair was still hanging out close to the island.
Sally (Borden) Buteau, the previous loon biologist, is monitoring the site.

Several ponds w/ potential pair activity last year or this May, now have
less consistent loon activity (Daniels, Great Hosmer, Wapanacki, Bruce,
Greenwood, Knapp Brook (nested '06), Marshfield, Neal, Elmore). There is
a chance that loons were off the ponds during the survey periods.
Loonwatch will be July 21; there are still a few small lakes that are
unassigned. If anyone is interested in helping to survey a lake that
morning around 8 am, please contact me at the address below. For 2 ponds
where I removed nesting rafts this year, one pair has nested naturally
(Brownington) and one pair has not (Bald Hill). The Newark Pond pair
successfully produced 2 chicks from the island site after using a
nesting raft for many years.

I will be sharing stories around a the campfire at Stillwater State Park
on Lake Groton on July 7, 7 pm and will be giving a slide show
presentation at Seyon Ranch (also Groton area) on Wed., Aug. 1 at 1 pm.
Happy looning.

Eric Hanson, Vermont Loon Recovery Project Biologist