Author Archives: Jeff Ritterson

About Jeff Ritterson

Forest Bird Conservation Fellow

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!

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!

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!

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

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!

Tree cavities: home to many creatures

When we think about a bird’s nest, we usually conjure up the image of a cup-shaped tangle of twigs and dried grass, with perhaps some moss or strips of bark, cleverly placed in a bush or the limb of a tree.  Maybe that’s because these are the most visible types of nests, whose remnants are easily seen when the leaves drop each fall.  Nests of other birds a quite difficult to see, even in plain sight.  For example, the Piping Plover creates a just slight depression in the sand, and the Eastern Whip-poor-will nests directly on the forest floor, each with highly camouflaged eggs.

Yet another type of nest are those placed in the cavity of a tree.  Many common bird species are actually cavity nesters, including nuthatches, chickadees, titmice, bluebirds, woodpeckers and some owls.  Cavity nests provide protection from predators, shelter from weather events, and can be chosen with respect to the regional climate.  For example, in northern latitudes woodpeckers are known to orient their cavities south towards the sun, so that their young will stay nice and toasty in the nest.

Pileated Woodpecker family; adult male on left, female on right. © Kim Nagy

Woodpeckers are particularly important in the world of cavity nesters.  While cavities can occur naturally in trees, most species are poorly suited to excavate their own cavities, and often rely on holes created by woodpeckers.

Cavities usually begin with a fungal infection, which creates a soft inner wood that is easy to excavate.  This condition is most common in older dying trees, which eventually become dead standing trees (called snags) and continue to be a good resource for cavity nesters.  Unfortunately, dying trees and snags present inefficiencies to timber production, and a history of land clearing and forestry practices have limited snag numbers.  Meanwhile, populations of woodpeckers and other cavity nesters can suffer if there are too few cavity trees available.

The good news is that forestry can also help to increase the number of cavity trees.  For example, the maintenance of large dying trees and snags is promoted by Mass Audubon’s Foresters for the Birds program.  This program, a partnership between Mass Audubon, MassWoodlands Institute, and the Mass Department of Conservation and Recreation, provides assistance to landowners who wish to manage their woods for bird habitat with sustainable forestry practices.

Empowering private landowners is critical because they own the majority (75%) of forests in Massachusetts.

— Jeff Ritterson, Forest Bird Conservation Fellow, Mass Audubon

Northern Flicker (yellow-shafted) adult female with young in cavity nest © Cynthia Rand

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

Bird-friendly Forestry at Elm Hill

These 17 birds were chosen to represent different forest habitats and management options in the Massachusetts Foresters for the Birds program.

Mass Audubon’s Foresters for the Birds program provides assistance for private landowners to manage their forests for bird habitat. Empowering private landowners is important because about 75% of Massachusetts’ forests are privately owned, and management on these lands will be necessary to address conservation needs on a landscape scale.

To promote the program, and to engage and educate the public, we are creating a long-term demonstration site at our Elm Hill wildlife sanctuary in Brookfield and North Brookfield. The first step: develop a 100-year forest management plan for Elm Hill. To do this we are working with a forester who was trained in our Foresters for the Birds program.

In addition to mapping different forest resources, and describing the amount and value of the standing timber, this plan also includes an assessment of the current bird habitat and recommendations for improvement. For example, the structure of the forest understory and midstory, where many birds place their nests, are described in each area of the forest.

The plan also includes strategic locations for the placement of early successional habitat. We are currently reviewing initial drafts of the plan, and working with our forester to iron out the nitty gritty details.

Once the plan is complete, we will then undergo active forest management on the property (probably next year), which will include things like removing invasive plants, and selectively removing trees to improve the composition, health, and resiliency of the forest.

We are also designing a bird monitoring study which will investigate how effective our forestry practices will be.  Because on-the-ground management will not happen until well after this year’s breeding season for birds we have the opportunity this year to characterize how birds are currently using the forest. Comparing that data to similar data collected post management will help us adapt our future efforts to maximize the benefits to our birds.

Beginning as soon as this summer, we will invite foresters, landowners, land trusts, and other conservation entities to visit the property and see how they can manage their woodlands for birds and other wildlife.

Keep checking back for more updates as we nail down our plans and begin the bird monitoring. For more information about the project, see our previous blog post.


Photo credits From top left: American Woodcock © David Larson; Black-and-white Warbler © David Larson; Black-throated Blue Warbler © John Harrison; Black-throated Green Warbler © John Harrison; Brown Thrasher © Patricia Pierce; Canada Warbler © David Larson; Chestnut-sided Warbler © David Larson; Eastern Wood-Pewee © Fyn Kynd; Eastern Towhee © John Harrison; Mourning Warbler © Gerard Dewaghe; Northern Bobwhite © Paul McCarthy; Northern Flicker © Richard Campbell; Ruffed Grouse © Richard Johnson; Veery © Mark Thorne; White-throated Sparrow © David Larson; Wood Thrush © Sheila Carroll; Yellow-bellied Sapsucker © John Harrison