Tag Archives: birds

Licorice In The Sky: A seasonal gathering of crows

Crows © Craig Gibson

An annual late autumn phenomenon in New England is the spectacular crepuscular gathering of American Crows into large nocturnal communal roosts. Felt by many to be large, raucous, and often pesky, crows in fact are intelligent, crafty, and creative survivors in a world heavily populated with humanity.  A crow aficionado ever since kidnapping a baby American Crow from a nest for a pet in my boyhood (don’t try that at home), I have been fascinated by crows.  Their myriad vocalizations, their ability to count at least to three, to eat practically anything, and to survive seemingly everywhere are collectively worthy attributes. But to fully appreciate the magnificence of crows in all their glory is to observe them at a winter roost.

To dispel the erroneous perception that American Crows are sedentary residents in Massachusetts throughout the year is to visit any of the leading autumn hawk watching sites in Massachusetts from late September to early November. As autumn’s foliage is acquiring its brilliance and then falling, small groups of crows daily stream southward from northern New England and eastern Canada, some following ridge lines and valleys, others the course of major river ways or the seacoast. As fall transitions to winter these northern migrants join more southerly resident crows every evening to form what are often aggregations of many thousands of individuals.  Wherever these nightly roosts happen to be, the late afternoon and nightly behavior of the crows within the roosts is a matter of considerable interest to the careful and dedicated watcher.  And there are lots of unanswered questions surrounding these winter roosts.

For example one might assume that every evening crows from far and wide simply fly directly to a communal roost site for the night, or that in the morning the crows utilizing a roost might routinely head for the same daytime foraging areas.  Not only are these assumptions untrue, they also offer insight into the mysteries of crow behavior.  Normally relatively solitary during the mid-spring nesting season, by mid-summer crows become increasingly gregarious, and by winter they have gathered into large roosts that may contain many thousands of individuals from great distances away.

© Craig Gibson

The behavior of crows near these evening roosts is particularly curious, if not mercurial.  For instance, from night to night crows approaching a roost will regularly make several pre-roosting stops (called staging areas), sometimes more than a mile from the final roost site.  These short stops are generally accompanied by much raucous vocalizing, before the birds present often suddenly depart and head off to another staging site where this behavior is then repeated.  This may occur several times before dark within a several mile diameter area of the final roost, and the staging areas may change location from day to day.

Finally, during deep dusk or shortly after dark, most of the birds in these staging areas will make a last and often silent flight to the ultimate roost site.  Surprisingly for birds as timid and wary as crows normally are during the day, at these nighttime roosts the birds often perched on bare, leafless deciduous tree branches where it is sometimes possible to literally walk under roost tree without disturbing them – something that would be virtually impossible during the day.

American Crow © Craig Gibson

Undoubtedly a number of important functions occur in these enormous winter roosts.  One is the opportunity for crows in a winter roost to “meet other crows.”  Since crows do not breed in their first year after nesting, these roosts may serve as “dating bars” for un-mated immature crows to meet at the winter roost, then eventually breed for the first time in the spring with mates established in the winter roost.  Similarly, first-year immature crows probably learn what it truly means to be a crow in a winter roost.  They likely acquire important winter foraging skills, learn how to avoid predators and other related dangers, and how to modify the many nuances of complex crow vocabulary.  While seemingly speculative, there is also good evidence to reinforce and support these concepts.

To best appreciate some of the spectacular mysteries described above, currently there are few better places in eastern Massachusetts to experience them firsthand than a huge, well established American Crow and Fish Crow roost located in the city of Lawrence.  This Lawrence roost has been well described in a previous Distraction Display post.

So to appreciate one of winter’s most impressive avian spectacles, try spending a late afternoon in the months ahead near the New Balance building in downtown Lawrence adjacent to the Merrimack River and behold the sight of Licorice in the Sky for yourself.

 

Give the gift of birds this holiday season. You can make a gift to Mass Audubon in honor of your loved ones.

 

Bird Conservation on the Road in Iceland

Hrisey Island © Margo Servison

From June 12–21 two members of the Bird Conservation team, Jon Atwood and Margo Servison, were privileged to visit Iceland with a Mass Audubon Natural History Tour. Along with 14 other travelers, we saw incredible geology, waterfalls, geysers, flowers, sea cliffs, and landscapes that can only be described as ‘otherworldly’. Oh, and lots of birds—74 species, the majority of which are seldom seen in North America, and nearly all of which were seen by all trip participants.

European Golden-Plover © Margo Servison

It was an amazing experience, to be in a world where the dominant bird species were shorebirds, waterfowl, and seabirds—there were only about 10 species of songbirds. Black-tailed Godwits, Red-necked Phalaropes, Gyrfalcon (even including a nest with 3 chicks), Atlantic Puffin, and European Golden-Plover were the trip favorites. And our super-fabulous local tour guide (Trausti Gunnarsson), one of those people who knows everything about everything, made the trip far more than simply a great birding experience.

Red-necked Phalarope © Margo Servison

To join Mass Audubon on two NEW Iceland birding tours next year, watch this website.

 

The Curious Case of a Barn Owl in Lexington

Among the half-dozen breeding owl species in the Commonwealth, the nearly cosmopolitan Barn Owl (Tyto alba) is clearly one of the most unusual.

Almost completely nocturnal (active at night), Barn Owls are so inconspicuous that they can sometimes go undetected even in localities where they may be fairly common. In Massachusetts, the raspy nocturnal shrieks of this owl are seldom heard away from their principal year-round nesting areas on Martha’s Vineyard and Nantucket, where they are close to the extreme northeastern limit of their range in eastern North America.

In Massachusetts, any Barn Owl found away from their favored haunts on the offshore islands is decidedly unusual. Consequently, the recent discovery of a dead Barn Owl on the surface of the snow at Dunback Meadow in Lexington (reported to our Wildlife Information Line) was most notable.

Dead Barn Owl found in Lexington © Marj Rines

Out of context the frozen corpse of a Barn Owl in Lexington might simply seem to be an anomaly. However, when all the facts are considered, it may not be as anomalous as it first appears.

At over 170 acres, Dunback Meadow is the largest conservation property in Lexington and it is comprised of a variety of habitats including an extensive open wet meadow and a pine grove. This combination of habitats is highly favorable to several species of small rodents and shrews, most notably the Meadow Vole (Microtus pennsylvanicus).

The Meadow Vole is frequently the number one prey species for several open country foraging raptor species, especially Northern Harriers, Rough-legged Hawks, Long-eared Owls, and Short-eared Owls. In winters when any given field is heavily populated by voles, some of these raptors occasionally become concentrated, much the way high populations of lemmings may concentrate jaegers and Snowy Owls in Arctic tundra areas.

This winter two Rough-legged Hawks and as many as four Long-eared Owls have regularly been recorded at Dunback Meadow – an indication that the vole population in the meadow is probably high this season.

Add to the abundance of food the recent bitter cold wave accompanied by a foot or more of newly fallen snow, and suddenly there is a combination of extreme stressors for a semi-hardy, rodent-eating raptors like Barn Owls trying to survive at the northern terminus of their range. But why was the Barn Owl in Lexington in the first place?

While the definitive answer may never be truly known, it is plausible to think that the Lexington Barn Owl was a wandering individual that was attracted by the same high concentration of rodents that had attracted the Rough-legged Hawks and the Long-eared Owls. But when it was suddenly confronted with a bitter cold wave accompanied by a foot of fresh-fallen snow, it probably became over-stressed and starved to death.

And from a belated report of a Barn Owl in a nearby garage several days previous to its being found dead on the snow, it seems likely that the owl may have been in the area for a period of time before meeting its demise due to starvation and the frigid cold weather.

The Lexington Barn Owl was spotted in a garage prior to being found dead © Charles Hornig

Patriots on the Move: tracking the migration of Great Shearwaters

While New England football fans are anxiously following the fortune of the New England Patriots, ornithologists at the Stellwagen Bank National Marine Sanctuary are tracking the trans-equatorial movements of Great Shearwaters (individuals in this year’s group are named after Patriots players).

Through the use of sophisticated satellite technology, tiny transmitters now have the capacity to follow the movements of birds and secretive mammals more than a hemisphere away practically in real time.

Great Shearwater ©Peter Flood

Followers of Distraction Displays may recall that in late summer seabirds called Great Shearwaters made headlines when exceptional numbers were observed feeding on many thousands of Menhaden (small forage fish) in the surf-line at Provincetown on the tip of Cape Cod. Although most of these shearwaters have long since retreated toward their nesting grounds on the remote archipelago of Tristan du Cunha deep in the South Atlantic Ocean, scientists nonetheless now know precisely where some individuals are located!

A size comparison of one of the solar PTT transmitters used in the project and a standard U.S. penny. ©NOAA/SBNMS

While satellite tracking has been used to monitor wildlife for 20 years or more, the weight and size of transmitters today makes it possible to follow wildlife significantly smaller than eagles and bears. This summer, waterproof transmitters called PTT (Platform Transmitting Terminal) tags weighing only 12 g and manufactured by Microwave Technology were affixed to shearwaters off Cape Cod during the month of August.

Of nine tags originally affixed to Great Shearwaters and one to a Sooty Shearwater this summer, one is still generating round-the-clock signals from Argos satellites orbiting the earth at approximately 528 miles above the ground. The unique signals generated by the transmitters are regularly received by Argos and eventually made accessible to the researchers who are mapping the movements of the shearwaters. Needless to say the technology involved is complex, but the information gathered is elegant.

All 10 tagged shearwaters as of 1/4/2018. ©NOAA/SBNMS

The 10 shearwaters tagged this summer were all named after New England Patriots players. Of the 10 tagged shearwaters, only Gronkowski’s transmitter was still sending signals on January 2, 2018. Gronkowski crossed the equator on December 19, and as of Jan. 2 was at 16.5 degrees South in deep water (>2000 meters) off the coast of Brazil near Banco Minerva—a semount <100 meters deep. Go Gronk!

Gronkowski as of 1/2/2018 ©NOAA/SBNMS

Cooks crossed the equator on December 12, but its transmitter stopped working on Christmas Eve at 27 degrees South in deep water (>2500 meters) off of Paraguay.

Cooks 12/24/2017 ©NOAA/SBNMS

McCourty’s tag stopped working on December 19, hours after crossing the equator. Edelman was still in the mid-Atlantic on Dec 12, and unfortunately Brady’s Sooty Shearwater transmitter cut out while the bird was off Morocco in mid-October.

Edelman 12/12/17 ©NOAA/SBNMS

All of the tagged shearwaters were aged by plumage to be either one or two years-old, and most will not likely return to Tristan du Cunha this winter because few are likely to attain breeding age until they are at least 5-6 years-old. These sub-adult individuals will very likely remain on the Patagonian Shelf until March/April before beginning their northward migration, which will initially bring them up the east coast of South America before reaching North Atlantic waters and the Gulf of Maine.

Having the ability to track individual Great Shearwaters in this way affords ornithologists not only a fine way to chart how this highly pelagic seabird uses the entire Atlantic Ocean in the course of a year, but also a way to map prime foraging and other concentration areas while they are in Gulf of Maine as well as elsewhere in the Atlantic Ocean. This information ultimately enhances the ability to identify oceanic regions of highest conservation concern. Read more about this fascinating project >

Wings over the Water: a seasonal parade

It was gray and overcast, the sea was churning, and the wind was fresh from the Southeast – perfect conditions for watching a parade in early November….and watch we did!  Our viewing location was North Beach on Cape Cod’s back side, all the way from East Orleans to Chatham.

“Marching” in this winged parade were over 40,000 sea ducks and seabirds, all headed southward in a more or less continuous passage emanating from destinations as far away as Alaska, western Canada, James Bay, Labrador, the Gulf of Saint Lawrence, and Newfoundland.  This timeless event was part of the annual migration of vast numbers of waterbirds, all originating in nesting grounds far to the north, and all bound for winter destinations well to the south.

The departure of waterbirds escaping the rigors of sub-arctic and boreal winter is part of a great migratory cycle that has evolved through the millennia into one of the most magnificent autumn spectacles to be witnessed on the Atlantic Coast of North America.  When migration conditions are ideal, the number of birds involved may exceed extravagant!

Common Eiders © Peter Flood

And so it was on November 5, 2017.  Between 8:30 a.m. and 3:30 p.m. my companion and I tallied approximately 12,000 Common Eiders, 18,000 Black Scoters, 5000 Great Shearwaters, 3000 Northern Gannets, 100 Razorbills, 400 Black-legged Kittiwakes, and 550 Bonaparte’s Gulls.  When combined with lesser numbers of numerous other species recorded that day, we estimated we had seen over 44,000 waterbirds in approximately seven hours of more or less continuous watching!

The dynamics and precise timing of such movements varies from species to species, but the net effect is unequivocal—the birds moving under such conditions are singular in their purpose, and all are taking advantage of weather frontal conditions and wind directions in ways that will maximize their migratory efficiency.

On November 5,

  • The sea ducks (e.g., Common Eiders) were flying in linear or loosely organized groups, often numbering in the dozens or low hundreds, sometimes flying low over the wave troughs, and sometimes well above the sea surface.
  • The powerful gannets on the other hand tended to fly high, often more than 50 meters above the sea, occasionally turning abruptly and plunging into the sea to catch a fish during their journey.
  • The shearwaters scaled like skipping stones over the sea as far as the eye could see, alternately using the wind between the wave troughs to carry them upward well above the waves, and rapidly gliding downward between the waves to catch another updraft that would carry them skyward again.
  • The more delicate and tern-like Bonaparte’s Gulls stroked along in small parties relatively close to the beach, while further off shore, football-shaped Razorbills would periodically rocket southward between the wave troughs on stubby wings that reminded one of flying penguins.

All this motion, and all headed in the same direction, even though few were bound for the same precise destinations.

Razorbills and Black Scoters © Peter Flood

Where are they headed?

Many of the Black Scoters and Common Eiders are likely headed for the shallow shoals off Monomoy or Nantucket where great submarine beds of blue mussels will sustain them through the winter. Other scoters however might not stop until reaching New Jersey or shoal waters off the Mid-Atlantic Coast for the winter.

The Northern Gannets will likely precipitate out along the continental shelf all the way from Cape Cod to the Gulf of Mexico.

Northern Gannets and gulls off Diamond Shoals, NC © Peter Flood

Most of the Bonaparte’s Gulls will no doubt spend the winter from North Carolina’s outer banks to Florida and the shores of the Gulf of Mexico.

The Great Shearwaters, however, will not stop until they arrive at their austral summer destination on the Patagonian shelf off Argentina, or the remote archipelago of Tristan de Cunha.

So many birds and so little time to accomplish these epic migrations!  However, for land-bound observers privileged to live in a region where these avian parades are seasonally visible from shore, these great waterbird movements represent one of the most dramatic natural parades to seasonally be observed in Massachusetts.

So the next day a brisk east wind is blowing on the heels of a cold front, grab a pair of binoculars and head for the nearest coastal headland!  You won’t be disappointed.

 

 

Hoots, Toots, and Who Cooks For You

Great Horned Owl © Phil Sorrentino

Halloween is typically marked by creepiness—creepy creatures, creepy people, and often creepy sounds.  While it could be true that some of the creepy Halloween sounds are uttered by ghosts, ghouls, and goblins, it’s also true that most are not!  In fact, some mid-autumn night sounds are actually produced by several of our most popular, if not enigmatic birds: owls!

Massachusetts regularly hosts five nesting owl species: Barn Owl, Eastern Screech-Owl, Great Horned Owl, Barred Owl, and Northern Saw-whet Owl.  Other Bay State owl species are either rare or only seasonal visitors.  Because most owls are active at night, much about the lives and activity patterns of owls often goes undetected or unobserved, and frequently it is only the voices of owls that give us a clue about their presence, sometimes without our even knowing which species is making a particular sound.

What are they saying?

Like most birds, owls vocalize to communicate information important to locating or communicating with their mate, their offspring, or other owls intruding into their territory.  And for these different functions, owls regularly use a variety of calls, some of which are the creepy sounds potentially heard by little trick-or-treaters during their nocturnal Halloween walks.

Great Horned Owls and Barred Owls Hoot

If you happen to live where there is good mix of deciduous (broad-leaved) trees and large white pines interspersed with open areas practically anywhere in Massachusetts, especially if the trees border a lake or pond shore, the deep, resonant hoo, hoo-hoo-hoo, hoo, hoo at dusk or dawn in the autumn is a clear indication that your neighborhood is occupied by a pair of Great Horned Owls.

Alternatively, if you should be awakened in the middle of the night by a rhythmic hooting that clearly sounds like who-cooks-for-you, who-cooks-for-you, allll, and if it has the quality of a distant barking dog, then the neighboring woodland is almost certainly home to a pair of Barred Owls.

Barred Owl © Derek Allad

Northern Saw-whet Owls Toot

While most of our local owl species are relatively sedentary throughout the year, the tiny Northern Saw-whet Owl is highly migratory in varying numbers during October and November.  Impressive numbers are annually captured and banded at several different owl-banding stations in eastern parts of the state—including Drumlin Farm.

Generally silent, territorial saw-whets typically give a long series of mellow, mechanical, whistled toot-toot-toot-notes that sometimes may continue for many minutes.  Primarily a denizen of coniferous forests in western Massachusetts, but also in the pine barrens of southeastern parts of the state, including on Cape Cod where it is probably second only to the much larger Great Horned Owl.  In fact, the Northern Saw-whet Owl is undoubtedly far commoner than most folks suppose.

Northern Saw-whet Owl © Heather Demick

Barn Owls Shriek

For the keen listener abroad at night on Martha’s Vineyard or Nantucket, one can occasionally hear the raspy shriek of a Barn Owl as it leaves its daytime roost, or forages for mice over open moorland.

Barn Owl © USFWS

Eastern Screech-Owls Whistle

At dusk on Halloween evening it would also not be surprising to hear the soft descending whistle (or whinnying sound) of the little Eastern Screech-Owl, the species which is undoubtedly the most common owl in Massachusetts.  Screech-owls also have a low, hollow, monotone whistle that can sometimes be heard throughout the night.

Eastern Screech-Owl (grey morph) © Nathan Goshgarian

Listen carefully and don’t fear!

So don’t be overly fearful of things that hoot or toot at night!  Indeed, go to the window or door and listen more carefully, or take an evening stroll with a flashlight and see if you can spot one of these fascinating creatures for yourself after dark.

 

Species Spotlight: Ovenbird

Ovenbird © Tom Murray

The Ovenbird, whose familiar tea-cher, tea-cher, tea-cher, tea-cher song is a dominant feature of the spring and summer woodlands of New England, was identified in Breeding Bird Atlas 2 as a species on the increase, especially in the central and eastern portions of the state. These increases were thought to reflect increased amounts of suitable forest habitat due to formerly agricultural land reverting to forest.

Change in Ovenbird distribution in Massachusetts between Breeding Bird Atlas 1 (1974-1979) and Breeding Bird Atlas 2 (2007-2011).

But the newly-released State of the Birds report tells a less optimistic story.  Ovenbird distribution in Massachusetts is likely to be adversely impacted by projected future changes in temperature and precipitation patterns. By 2050 the species will continue to occur statewide, but occupancy in eastern areas of the state may decline as the species’ climate envelope (their preferred climate) drifts northward, leaving Massachusetts near the southern limit of the species’ continental distribution.

Current climate suitability for Ovenbird in Massachusetts.

Climate suitability for Ovenbird in Massachusetts in 2050.

How to read the climate suitability maps >

Keeping Large Forest Tracts Intact Will Lessen the Stress Ovenbirds May Face

Research has found that Ovenbirds require large intact expanses of forest habitat for successful breeding. This could be in part due to the fact that larger undisturbed forests have lower risk of nest predation and brood parasitism. Therefore, maintenance of large tracts of mature forest is crucial to future conservation of Ovenbirds in Massachusetts. Such areas will continue to be threatened by suburban development and associated habitat fragmentation.

Additionally, climate change may add to the stress of losing intact core habitat, because warmer temperatures may reduce the soil moisture levels that influence Ovenbird’s food resources (mainly insect larvae gathered on the ground).

Conservation Is Needed for the Full Life Cycle of a Migratory Bird

Distribution of Ovenbirds during breeding (orange), migration (yellow), and winter (blue) periods. © Cornell Lab of Ornithology, Neotropical Birds

Ovenbirds migrate through the southeastern U.S., wintering mainly in the Caribbean, Mexico, and Central America – including areas that were recently damaged by Hurricane Irma. Throughout its annual life cycle it is vulnerable to habitat loss and degradation, window collisions, and predation by cats.

Conservation of Ovenbirds demonstrates the broad suite of actions that are important for most

of our Neotropical migrant songbirds. Efforts to reduce losses throughout the full annual cycle are important. Action must be taken on their breeding, migrating, and wintering grounds to effect positive change in the population.

How Can We Help Ovenbirds and Others?

  • Prevent forest fragmentation in the breeding range by supporting the efforts of local land trusts.
  • Ensure that your backyard is a bird-friendly sanctuary safe from cats and potential collisions with windows.
  • Support efforts to reduce window collisions at tall skyscrapers and other office buildings.
  • Donate to organizations focused on protecting lowland forest habitats in the Caribbean, Mexico, and Central America—actions directed toward all those efforts will help reduce the pervasive impacts of changing temperature and precipitation patterns on breeding Ovenbirds in Massachusetts.

Ovenbirds are often observed strutting (never hopping) like a chicken along the forest floor. © Tom Benson

Please consider supporting our bird conservation work by making a donation today. Thank you!

A Plethora of Pirates: Jaegers rule at Provincetown

First it was shearwaters—now it’s jaegers!

Earlier this fall the waters off Provincetown made news when an unprecedented concentration of thousands of Great Shearwaters was attracted inshore by a superabundance of small menhaden fish (a.k.a. peanut bunker) that were driven ashore by foraging mackerel. This influx afforded birders, fishermen, and the general public a unique opportunity to see these normally open ocean seabirds at practically arm’s length.

Now, several weeks later, exceptional numbers of jaegers have taken center stage in these same waters.  Dusky-colored and predatory, jaegers are gull-like seabirds that in North America nest on high latitude arctic tundra from Alaska to Labrador. Taking several years to mature and exhibiting high variability and a complexity of plumages, jaeger identification can confound even the most experienced observers.

Parasitic Jaeger (dark morph) © Peter Flood

Meaning “hunter” in German, the word “jaeger” (pronounced “yay-ger”) is well-suited to three closely related species—Pomarine, Parasitic, and Long-tailed—all distinctive in adult plumage because of two, long, pointed or twisted central tail feathers.  But far more exciting is the kleptoparasitic lifestyle of jaegers.  Kleptoparasites are species that obtain much of their food by stealing it from other species, which in the case of jaegers usually means smaller seabird species such as terns.

A Parasitic Jaeger pursues a Common Tern © Peter Flood

Parasitic Jaegers are the new rulers of the waters off Provincetown

In Provincetown it is Parasitic Jaegers that have been maintaining dominion over the hapless terns lingering off Race Point in recent weeks.  Literally dozens of jaegers are currently tracking the hard-working terns off Race Point, the ever vigilant pirates constantly on the lookout for terns carrying fish in their beaks.  Upon spying a fish-laden victim, a plundering jaeger will at once give aggressive chase. With fighter plane-like precision, one or more jaegers will pursue a target with aerial gymnastics hardly seen in any other bird species.  So skillful at piracy are jaegers that they are often able to catch a falling fish relinquished by an intimidated tern before the fish hits the water!

A Parasitic Jaegar prepares to catch relinquished fish © Peter Flood

In the days ahead as the last of the lingering terns head for South America for the winter, the aerial pirates that have been recently harassing them off Provincetown will begin to drift away, shadowing the terns all the way to their South Atlantic wintering quarters.  Although Parasitic Jaegers are capable of capturing fish or scavenging food on their own, during their non-breeding season at sea they generally prefer their criminal life style as a way to obtain food.  Come spring however, the jaegers will head north for their arctic nesting grounds where their diet will shift to small rodents or shorebird eggs and chicks.

Always predatory and always on the move, jaegers are fascinating seabirds that can only be admired when viewed in full pursuit of a fleeing tern, or when observed deftly flying amid the frothy troughs of a storm-tossed sea.

Get to P-town soon to see these spectacular birds for yourself!

Parasitic Jaegers pursue a tern © Peter Flood

Please consider supporting our bird conservation work by making a donation today. Thank you!

Species Spotlight: Northern Bobwhite

Climate change, like all environmental change, is bound to create losers and winners.  That is, while some species will experience climate-driven declines, others stand to benefit.  The Northern Bobwhite is one species that may be positively affected by climate change, according to Mass Audubon’s new State of the Birds report.

Northern Bobwhite range in North America ©National Audubon

The Northern Bobwhite is a species which reaches the northern fringe of its range in southeastern Massachusetts. According to the Massachusetts Division of Fisheries and Wildlife, Northern Bobwhites were once limited to coastal areas of Massachusetts, but likely expanded statewide following the clearing of land for agriculture during the 1820’s to 1840’s. However, a string of severe winters in the late 1800’s and early 1900’s may have wiped out bobwhites across the state, recovering only in the southeast which has milder winters.

Change in Northern Bobwhite distribution between Breeding Bird Atlas 1 (1974–1979) and Breeding Bird Atlas 2 (2007–2011).

 

Why Do Severe Winters Hurt Northern Bobwhites?

Northern Bobwhites gather together and form “coveys” in the fall and winter. © Missouri Department of Conservation

Recent research has confirmed the long-standing assumption that severe winter weather events (e.g., ice storms, heavy snow accumulation) can increase Northern Bobwhite mortality and thus suppress northern populations of bobwhites.

One hypothesis explaining the negative effect of severe winter weather on Northern Bobwhites is that too much snow accumulation can limit access to the bare ground, where they forage primarily for seeds. Unlike turkeys, bobwhites cannot dig through snow to find food.

Predicted Less-Severe Winters Could Help Bobwhites in Massachusetts in the Future

Massachusetts can expect to see less snow fall and less accumulation in future winters due to climate change, and this may bolster winter survival of Northern Bobwhites and allow them to expand their distribution from the southeast to other areas of the state.

However, although the climate may be more favorable for bobwhites, as shown by our maps below, successful colonization of new areas will depend on the availability of suitable habitat, such as early successional areas, scrubby field edges, and open woodlands with herbaceous ground cover.  Without this, the Northern Bobwhite may continue to decline in the state.

Mass Audubon’s work on the Foresters for the Birds program (of which Northern Bobwhite is a focal species) and habitat management on our sanctuaries are critical for the conservation and restoration of healthy forests and early-successional habitats and species in the state.

Climate Suitability for Northern Bobwhites

Current climate suitability for Northern Bobwhite

Projected climate suitability for Northern Bobwhite in 2050.

How to read the climate suitability maps >

Please consider supporting our bird conservation work by making a donation today. Thank you!

Flight of the Broad-wing: an epic in the sky

Every year, at about this time, dedicated hawk watchers and serious raptor aficionados begin paying particular attention to radar images and weather prognostications on the evening news. Indeed, some devotees even regularly take their vacation in the middle of September. So what’s so special about mid-September? To those in the know with an interest in hawk migration, mid-September is THE time to intercept the peak southward departure of the Broad-winged Hawk (Buteo platypterus).

Adult Broad-winged Hawks are 15 inches-long with a 24 inch wing-spread, a black tail crossed midway with a single wide, white band, a brown back, and rusty-brown underparts.  In flight they are compact, with broad wings that are pale underneath and traced with a thin black border around the edges (as shown in the above photo). Ranging throughout most of the eastern United States and southern Canada west to Alberta, Broad-wings spend much of their summer hunting amphibians, snakes, small mammals, and birds to feed their young.  However in mid-September it is the spectacular autumn migration of this species that annually captivates and mesmerizes hawk watchers, and often even the general public as well.

Unlike other raptors (or most other species of birds for that matter) few have such a telescoped seasonal departure as the Broad-winged Hawk. With seemingly mathematical precision, much of the North American breeding population typically initiates its southward migration sometime between September12–20.  Depending upon weather conditions, in some years this time window becomes even more compressed, occasionally with many thousands of individuals passing favored observation sites literally within a few hours. Here in Massachusetts, Wachusett Mountain in Princeton, Mt. Watatic in Ashburnham, and Mt. Tom in Holyoke are among the better places to witness this phenomenon.

In mid-September Broad-wings across much of their breeding range wait strategically for the passage of cold fronts accompanied by falling temperatures and light winds from the north side of the compass to begin their migration.  Under such conditions the hawks almost simultaneously begin lifting up from the summer woodlands where they nested to search for rising warm air masses called thermals that will help eventually transport them to South America for the winter.

Using such thermals to carry them skyward many thousands of feet, eventually the Broad-wings break out of the thermals and travel to another thermal, often several miles away, by means of long, high-speed power glides that cause them to gradually lose altitude at the same time.  Once they reach another thermal, they then ride the new “escalator” skyward. Because hundreds of Broad-wings are using this same strategy, on a good day for migration, a large thermal often contains many hundreds of tightly soaring individuals all rising upwards at the same time.  In hawk parlance such an aggregation is called a “kettle” (shown below).

On days favorable for migration, many thousands of Broad-winged Hawks make their way southward at the same time using this combination of riding warm air thermals upward for lift, and then power gliding to another thermal so they can regularly cover hundreds of miles a day under ideal conditions. The migration tends to follow the southwesterly leading line created by the Appalachian Mountains. Between the thermal-and-glide strategy, and wind lift created along Appalachian ridgetops, the hawks gradually make their way to the Gulf Coast, where they gradually “turn the corner” in southern Texas to avoid crossing the Gulf of Mexico, and then make their way into Mexico and south through Central America, and finally into northern South American where most will spend the winter.

Not surprisingly there are variations in this strategy along the way, including several world-famous hawk-watching bottlenecks where, with several other species, they pass through Mexico, Costa Rica, and Panama.  While this is by no means the full story, it is the essence of how each year this magnificent raptor accomplishes one of the most amazing autumn migrations in the western hemisphere.

 

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