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 >

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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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Surveying Wildlife at Elm Hill

In order to characterize the bird community at Elm Hill, point count surveys were performed at 24 locations within forested areas of the sanctuary.  During a ten minute period, the species of each individual bird is recorded, as detected by sight or sound, within 50 meters.  This gives us information on the abundance of each species and the overall species richness (number of species).  As is typical, each location was surveyed 3 times, and this yielded 789 detections of birds representing 51 species!

As discussed in previous blog posts about the development of a Foresters for the Birds demonstration site at Elm Hill, these surveys were done to establish a pre-management baseline, which will then be compared with conditions after management.  Wait a minute… 51 species!?!  Is management really necessary?

51 species may sound like a lot, leading to the conclusion that the forests are already providing good habitat.  That may be true, but for what species?  Upon closer examination of the data, we can see that many of the species we recorded (e.g., nuthatches, titmice, and catbirds) are quite common, thriving in our woodlands and backyards alike.  Others, such as Barred Owls, naturally occur at low densities, so we wouldn’t expect to find many of them.

It’s those species that we conspicuously did not detect, or recorded very few of, that we are managing for.  For example Black-throated Blue Warbler and Ruffed Grouse were not recorded.  These species rely on some degree of disturbance to the canopy, creating vegetative growth in the understory and a mix of tree ages in the forest.  These are conditions that can be created through sustainable forestry, and it would not be unreasonable to expect these, and other species of conservation concern, to show up at Elm Hill after appropriate habitat management.  Time will tell.

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

Hot Off the Press! State of the Birds 2017

Black-capped Chickadee may face an uncertain future in Massachusetts. ©Bill Thompson, USFWS

It is with great pleasure that we announce that our third edition of State of the Birds is now available. State of the Birds: Massachusetts Birds and Our Changing Climate focuses on what the future may hold for the breeding birds of Massachusetts as the climate continues to change.

Our last two State of the Birds reports, released in 2011 and 2013, compared the past to the present and identified changes in Massachusetts bird populations. The 2017 edition builds on that work by using science to predict the future.

Climate Matters For Birds and People

Most birds have limited distributions and, to some extent, climate controls the range of those distributions. To glimpse the future, we used a statistical analysis called climate envelope modelling.

Put simply, climate envelope modelling uses real bird and climate (various measures of temperature and precipitation) data to define the preferred climate of a bird species—their “climate envelope”—as it is today. Then the models substitute predicted values of the climate variables into the equation to project a bird’s climate envelope in 2050.

Using the results of our analysis, we assigned each of the 143 species analyzed a “Climate Vulnerability” score. There were some expected results and some surprising results. The overarching message was that birds are already feeling the effects of climate change and even some of our most common birds will probably experience further changes by 2050.

It’s In Our Power to Change the Future

While climate change can feel like an overwhelming problem, it is a problem that we can solve. Much like Scrooge in A Christmas Carol, we are being shown a possible future for our birds, and, just like Scrooge, we can take action today to change that future.

Visit the website, download the report, and share it with your friends and family. If we work together we can protect birds, wildlife, and ourselves.

Check out the article in the Boston Globe about the State of the Birds report.

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

Beachfront Armageddon: A fish tale and a seabird saga

For several weeks the sandy beaches at Race Point and Herring Cove Beach in Provincetown have witnessed a spectacular and practically unique confluence of seabirds and fish.  The players in the P-town saga have been Atlantic menhaden (Brevoortia tyrannus) and Great Shearwaters (Ardenna gravis).

Great Shearwaters are Ring-billed Gull-sized seabirds that maintain their breeding terminus at Tristan de Cunha, a remote archipelago located deep in the southern hemisphere approximately halfway between the tip of southern South America and Cape Horn in South Africa.  Annually most of the world’s population of Great Shearwaters migrates north across the equator to spend the austral winter in the northwest Atlantic Ocean. By late summer most of the adult population has begun the long return journey back to Tristan du Cunha to nest, but the non-breeding sub-adult population regularly remains in North Atlantic waters until late fall.  While in the northern hemisphere Great Shearwaters typically remain on remote fishing banks far off the New England and Atlantic Canadian coasts where they forage on baitfish such as sand lance, capelin, sea herring, or squid and fish bycatch obtained by tracking commercial fishing vessels.

Each high tide left behind a swath of dead menhaden.

Menhaden are a super-abundant forage fish often characterized as one of the most commercially important fishes occurring along the Atlantic coast of the United States, particularly from Massachusetts to the Carolinas (Bigelow and Schroeder’s Fishes of the Gulf of Maine, Collette & Klein-MacPhee, eds., Smithsonian Press, 2002).  Due to their super abundance, immature Menhaden typically less than 2” in length are important fodder for a variety larger predatory fish, marine mammals, and seabirds.  For reasons not always clear, the literature suggests that they are periodically subject to mass late summer stranding and mortality events. These mortality events most often occur in shoal water habitats such as the heads of tidal creeks or small coves like the Herring Cove area in P-town where they may suffer from oxygen depletion or are driven ashore by predators (op.cit.).

Regardless of the explanation, a massive menhaden mortality event took place during the last couple weeks of August and early September.  Most notable however was the fact that unprecedented numbers (i.e., many thousands!) of Great Shearwaters appeared inshore to feast on the abundant fish.  For many days in a row, on each falling tide the voracious shearwaters literally swarmed in the surf picking off the tiny fish like popcorn. For a normally completely pelagic species that spends most of its life out of sight of land, this behavior was most unusual and provided birdwatchers, fisherman, and beach-goers a rare opportunity to observe these interesting seabirds at literally pointblank range!

Check out this video to see what this phenomenon looked like.

 

On the Road: National Adaptation Forum

by Daniel Brown and Jeff Collins

Jeff Collins, Director of Conservation Science, and Daniel Brown, Climate Change Program Coordinator, attended the National Adaptation Forum (NAF) in May in Saint Paul Minnesota.

The National Adaptation Forum is a gathering of scientists, educators, and community leaders working to address the challenges of climate change.

The field of climate adaptation is advancing rapidly, and Daniel presented on Mass Audubon’s work with communities to identify local critical weather thresholds. Thresholds are used to plan for emergencies and design infrastructure, but those thresholds are often outdated and difficult to measure. On top of that, climate change is making extreme weather events change over time, creating a great deal of uncertainty for communities looking to stay safe, healthy, and resilient. That may be soon changing, however, based on the assessment of experts at NAF. Land managers and city planners may soon get a whole host of new tools that will help plan for the size and frequency of future extreme weather.

Some of the most common themes discussed at NAF were environmental justice and the need for ecological conservation efforts to make communities more resilient. For years, the focus has been on what’s called “green” infrastructure—using restored landscape types like parks, greenways, and rain gardens to lessen the effects of climate change. Now the focus seems to be shifting to protecting undeveloped open areas and letting nature provide a resilient, adaptable places for people and wildlife. Mass Audubon’s Mapping and Prioritizing Parcels for Resilience (MAPPR) tool will help with that effort by allowing land conservationists to identify parcels that are a high priority for protection.

Climate change poses many challenges for our communities in the decades ahead. Underserved communities with less access to open space tend to be particularly vulnerable, but the inspiring work of so many institutions across North America gives plenty of reasons to be hopeful.

 

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The Treasure Islands of Essex County

by Chris Leahy, Gerard A. Bertrand Chair of Natural History and Field Ornithology emeritus

Halfway Rock © Chris Leahy

There is something about islands. Their remoteness generates a certain mystique.  Even islands inhabited by people have an aura of “away-ness,” and uninhabited ones stimulate visions of hidden treasures of one kind or another. There is also an ecological significance to islands: their plants and animal communities are often different from those of even nearby mainlands; their isolation from other populations promote evolutionary change; and they may act as refuges for certain species because they are hard to reach by predators.

The coastal waters of Essex County from Nahant Bay to Cape Ann are dotted with more than 50 islands ranging in size from small rocky “skerries” which are nearly submerged at high tide to the well-wooded 83-acre Great Misery Island, two of them populated at least seasonally. In 2002 these were formally designated as the Essex County Coastal Birds Islands Important Bird Area*, due to their breeding populations of water birds that rarely nest on the mainland, including a number of rare or uncommon species.

Straitsmouth Island © Chris Leahy

This summer Mass Audubon’s Conservation Science Department, supported by a grant from the Nuttall Ornithological Club, and the help of several generous private boat owners began a survey of these islands with the following basic objectives:

  • Developing a comprehensive understanding of past and current bird survey efforts, data sources, and management activities.
  • Completing an assessment of current breeding bird activity on the islands.
  • Identifying existing stresses such as human use, presence of rats and other predators, vegetation change, and climate vulnerability.
  • Developing recommendations for future management in support of the breeding birds.
  • Raising public awareness of the importance of these islands through programming and networking with state and regional conservation entities.

The survey has already turned up a number of previously unrecorded breeding sites for wading birds and American Oystercatcher.  We will be publishing more detailed results in the near future.

 

*An Important Bird Area (IBA) is an area identified using an internationally agreed upon set of criteria as being globally important for the conservation of bird populations. The program was developed and sites are identified by Birdlife International based in Cambridge, England. Currently there are over 12,000 IBAs worldwide and 79 in Massachusetts.

 

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In the Field: Elm Hill

Scarlet Tanager © Ruby Sarkar

Past blog posts about our Elm Hill Sanctuary – a Foresters for the Birds demonstration site—have largely discussed the planning of forestry practices to manage and enhance bird habitat.  We kicked the project off last fall and winter, when our migratory birds were hundreds or thousands of miles away.  So, until spring arrived, we were not able to work much with the birds themselves.

A primary focus of the program is indeed birds and their habitat, so it is important to assess how effective any implemented forestry practices are.  This enables us to make adjustments to future management and maximize the benefit for birds.  We do this by monitoring how the birds respond.  At the earliest, on the ground management at Elm Hill will not happen until this coming winter.  However, we will need to compare the future bird response to current, baseline conditions.  A before-and-after, if you will.

Late May through early July is the ideal time to sample breeding birds.  Migration is over, so all the birds have arrived and will likely remain through the season.  They are on breeding territories and actively singing, which helps us to detect their presence.  During this time we can begin to answer some important questions.

For example, which species are present, and what are their general habitat preferences?  How many species are present?  How many individuals of each species are present?  Is a particular species absent that we may have expected?  Answering questions like these help us to characterize the current bird community.  Answering the same questions after habitat management will help us assess just how effective our efforts were.

Wood Thrush nest © Michael Ross

This is why, with the help of volunteers, Sheila Carroll and Mark Lynch, we recently completed a series of point count surveys at Elm Hill, all within areas that are slated for management in the near future.  With this initial information in hand, we will eventually see how things change after management, which is geared towards helping species in need of conservation action.  The next step will be to dig into the data, and some results will be shared in future Elm Hill updates.  Stay tuned!

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How birds sing such intricate songs

The colorful bursts of flowers and the familiar smell of thawing soils that we all associate with spring is always accompanied by the wonderful sound of bird song.  There is nothing quite like waking early enough to experience the dawn chorus, where male birds, representing a slew of different species, are persistently singing to secure a breeding territory and attract a mate for the season.

Wood Thrush © Sheila Carroll

The beauty and complexity of these songs is attributable to a unique organ that most birds possess, called a syrinx.  Located where the trachea – commonly known as the windpipe – splits into the bronchial tubes before entering the lungs, the syrinx has two symmetric halves, each capable of producing sound independently.  This enables songsters to make seamless changes in pitch, articulate a complex burst of short notes, and even sing two tones at once.

Some of our most impressive singers are the thrushes.  This family (Turdidae) includes species such as the American Robin and Eastern Bluebird, but perhaps the most impressive singers are those which inhabit deep forests.  Some of these songs, such as the Wood Thrush’s and Veery’s, are featured on the following website, where you to listen at regular speed as well as slowed down:

http://www.wildmusic.org/animals/thrush

When you slow the songs down you can really hear the intricacies.  Put some headphones on to really have a close listen, and maybe you will have a fuller appreciation the next time you hear a bird singing.

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

Standing Together for Migratory Birds

By Jeff Ritterson, Bird Conservation Fellow

On Tuesday, May 9th, I was in Washington D.C. at Standing Together for Migratory Birds—a legislative briefing on federal migratory bird conservation programs.  With recent political changes in Washington, it may seem that support for these programs, and the crucial funding they provide, is on the chopping block.  But that’s not necessarily the case, and here’s why.

As conservation biologists, we understand that humans are inextricable from natural world, and that healthy and functioning ecosystems are inherently good for us.  However, we also understand that money talks, and this was a theme of the legislative briefing.  In remarks given by Senator Whitehouse (Dem-RI), he stated that, more often than not, humans come first on Capitol Hill, and every last issue gets monetized.

With that in mind, the American Birding Association presented on the economics of migratory birds and wildlife watching.  For example, the U.S. Fish and Wildlife Service reports that in 2011 Americans spent about $15 billion on birdwatching trips and an additional $26 billion in related gear.  A presentation by Ducks Unlimited also showed that significant money is spent hunting waterfowl, and 98 cents of every dollar from federal duck stamps sales goes to the acquisition of habitat—more than 6 million acres since its inception in 1934.

Of course, these activities depend on the conservation of our migratory bird species, and that’s where federal programs come in.  For example, since 2002 the Neotropical Migratory Bird Conservation Act has provided about $60 million to fund over 500 migratory bird conservation projects.  Also, the Farm Bill funds conservation programs that successfully help agricultural producers and migratory birds.  For example, thanks to these programs, Whooping Cranes are now nesting in Louisiana farmland – the first state nest in 75 years.

However, it’s not just a federal handout.  Many programs require additional contributions—as much as 3 dollars for every 1 federal dollar provided.  This way programs stimulate conservation activity and non-federal support from sources such as private foundations and donors.

With such a sound economics, federal migratory bird conservation programs can receive support from both sides of the political aisle.  That said, they are periodically reviewed, and it is important to tell your senators and congressional representative that you support full funding of bird conservation programs.

 

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