Category Archives: Birds and Birding

The Greatest Black Hawk: An epic journey recounted

Posted on January 16, 2019 by Wayne Petersen
Great Black Hawk by John Harrison

Black hawks are hefty, Buteo-like hawks not too distantly related to the widespread and familiar Red-tailed Hawk (Buteo jamaicensis). There are several species, but most common are the Common Black Hawk (Buteogallus anthracinus) that sparingly nests in the extreme southern portions of the southwestern U.S. south to northern South America, and the Great Black Hawk (Buteogallus urubitinga) that primarily breeds from coastal Mexico south through tropical South America. Both species feed on a variety of creatures including reptiles, amphibians, crayfish, crabs, small mammals, and occasionally even birds.  Both black hawks are relatively sedentary and neither species is a long-distance migrant.

With this information in mind, it understandably came as a mind-blowing surprise to several ecstatic birders who saw and definitively photographed for 20 minutes a juvenile Great Black Hawk on South Padre Island on the coast of Texas, April 24, 2018.  But this is only the beginning of a saga! 

Fast forward to August 6 in Biddeford, ME, where the same individual Great Black Hawk was again definitively photographed and the images were matched exactly to the April sighting in Texas.  The hawk lingered in Biddeford until August 9 before once again disappearing, this time until October 29, when it showed up in Portland, ME! Only this time the elusive tropical raptor only stayed under cover until November 28 when it appeared in a different part of the city only two miles away.

Virtually as I write, this itinerant tropical raptor is still present in the vicinity of Deering Oaks Park, just west of downtown Portland where it has become headline news and is happily feeding on the plethora of gray squirrels inhabiting the urban park.  What will be its ultimate fate when the snow flies and the inevitable cold becomes extreme may never be known….but for now, this has to be the Greatest Black Hawk of them all!

A Birder’s First Christmas Bird Count

Posted on December 19, 2018 by William Freedberg

This is a guest post by Nick Tepper. A recent graduate from the University of Vermont, Nick is an up-and-coming expert on New England birds, a lifelong naturalist, and is currently fulfilling an AmeriCorps service year with Mass Audubon.

It was 5:30am on a frigid causeway in the middle of Lake Champlain– technically Colchester, VT, but we may as well have been in the Bering Sea given the arctic wind and cold. I remember stepping out of the car at our first site and walking the first steps of a two-mile icy bike path into the freshwater ocean. This was the inauspicious start to my first-ever Christmas Bird Count (CBC), in the winter of 2017. We could barely see, perhaps because the sun had not yet risen, or perhaps because of the 20mph winds that froze our eyelids shut. I spent the next hour or so shivering and trying to figure out what we were doing out there!  Why torture ourselves? Had we no self-respect?

Finally, the sun rose over the trees, and somehow in the –12-degree weather, it was warm. Looking towards the sunrise, we saw birds begin to appear in the dawn. A Snowy Owl was the first species we saw, glowing orange in the early light. What a moment to behold… its yellow eyes opening for seconds at a time to scan the lake for ducks, just as we did with our binoculars. That bird kept us warm all day. We ended up tallying 48 species, and I learned more about birding than I had in all my younger years memorizing plumage patterns, molts, and call notes.

A distant Snowy Owl perched on a block of ice in a watery, frozen marsh. Photo by William Freedberg.

Birding as defined by my first CBC was not a hobby, a job, or a passion— it was a mindset. More importantly, it is a mindset that people could share. If you participate in a CBC, you will inevitably make acquaintances, connections, and very likely some lifelong friends. For me, the best part of the CBC is that you do not need to be a seasoned birder to participate, you need only have an interest in birds and a pair of binoculars.

CBCs, Formerly Known As Christmas Bird Hunts

The Christmas Bird Count, now a grand tradition understood as an all-hands-on-deck census, was borne out of a more grisly 19th-century rite. CBCs were developed by conservation-minded ornithologists as replacements for a tradition known as the Christmas “Side Hunt.” Hunters would celebrate the season by taking “sides” after Christmas Day and filling the sky with bullets, with the goal of (quite literally) stacking up as many species as possible.

During the holiday season of 1900, noted ornithologist Frank M. Chapman piloted the idea for a Christmas Bird Census instead of a competitive hunt. On Christmas Day 1900, Chapman and 26 other counters pioneered 25 counts, counting 90 species. The count has since grown. Last year, 76,987 counters completed 2,585 counts internationally, tallying a total of 2,673 species! Even so, the CBC can always use more counters, and the birding community would love to have you along for the jolliest day of the year. 

Join Your Local Bird Count!

While some CBCs have already taken place, there are plenty more in Massachusetts before the year is up. Try getting in on one of the following:

  • The Concord CBC will take place on Sunday, December 30, and includes the towns of Concord,Lincoln, Acton, Maynard, Sudbury, and others.
  •  The Marshfield CBC is scheduled for Sunday, December 30 on the South Shore, and includes Marshfield, Duxbury, Hanover, and Pembroke.
  • The Newburyport CBC will take place next weekend on Sunday, December 23, and includes an abundance of saltmarsh habitats including Salisbury State Reservation, the famed Plum Island, and several towns on the North Shore.

Evening Grosbeaks Used To Be Common In MA. This year, They’re Back.

Posted on December 6, 2018 by William Freedberg

Just as ornithologists predicted, 2018 is shaping up to be a banner winter for a number of nomadic finches in the Northeast, especially Evening Grosbeaks. Having steadily declined as winter visitors since the 1970s, these predictably unpredictable birds are a welcome sight this year.

Evening Grosbeak (Creative Commons)

Irruption Years: Boom And Bust

Evening Grosbeaks, like several species of “winter finch”, rely on conifer seeds and berries whose yield in the wild (or “crop”) varies intensely from year to year. When cone and berry crops in certain areas of the boreal forest are strong, winter finches stay close to their breeding areas year-round. When cone and berry crops fail, winter finches become nomadic, sometimes moving hundreds of miles to the south and to lower elevations.

Even within the season, these birds move around a ton. After an historic number of Evening Grosbeak sightings this mid-November, things seem to have quieted down a bit. EBird records suggest that as many birds may have moved on from or even “overshot” Massachusetts and landed deeper into the mid-Atlantic.  This is unlikely to last though—new pulses of irruptive species will continue into the winter and there is still plenty of finch forage left in the trees.

Shifting Distributions

Misconceptions abound regarding Evening Grosbeaks’ status in Massachusetts, in part because this species’ distribution is in almost constant flux.

The last Breeding Bird Atlas showed these grosbeaks breeding in small but growing numbers in the western highlands of Massachusetts, despite a precipitous decline in winter observations statewide. Climate change is shifting the general range of this species northwards, and the prognosis for breeding grosbeaks in Massachusetts–which rely on climate-sensitive and declining conifer species– is grim. Indeed, eBird data suggest they may have already declined since the last atlas.

Birders who were around in the 1960s and 70s often fondly remember the times when Evening Grosbeaks were abundant every couple of winters. It’s a popular misconception that this species was naturally abundant in Massachusetts, and that climate change alone is responsible for their shifting status.

In fact, breeding Evening Grosbeaks were historically restricted to northwestern North America. Their population slowly advanced south and east during the latter half of the 19th century until a significant irruption brought them into the northeast in 1890. The 1890 irruption carried them as far east as Revere Beach, and in subsequent winters, the birds returned in larger and larger numbers. Nearly 14,000 Evening Grosbeaks were recorded in the 1972 Christmas Bird Count, but in the 1990s and 2000s, their winter range shifted away from Massachusetts dramatically– despite a modest increase in local breeders.

This Year’s Conditions

Winter finch irruptions do not only reflect a snapshot of food availability in the current year, but are affected by longer-term trends. For example, 2017 was an excellent year for cone crops in Manitoba, Ontario and Quebec, leading to increased reproductive success for seed-eating birds. This year, winter finch numbers are high as a result– in a year when food happens to be scarce.

This makes it a particularly good year to put out black-oil sunflower seeds, Evening Grosbeaks’ birdseed-of-choice. While many Evening Grosbeaks have been reported eating crabapples and ornamental tree fruits this winter, they’ve also been showing up in strong numbers at feeders.

Check out Your Great Outdoors for more information on this year’s winter finch irruption! 

Licorice In The Sky: A seasonal gathering of crows

Posted on November 13, 2018 by Wayne Petersen

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.

 

November Is Western Vagrants Month: 6 Species To Watch For

Posted on October 26, 2018 by William Freedberg

Every November, most migratory birds of the American West are on their way south, but a handful always end up in New England. While it might seem surprising to find a Western Kingbird along the chilly Massachusetts coastline, it can be fairly easy to predict which weather conditions will bring a small wave of western vagrants into the Northeast.

Fronts and storms are key, especially those bringing winds from the southwest. After the breeding season, some migratory species disperse in seemingly random, weather-dependent ways before continuing to the tropics. Additionally, most populations of migratory birds include a few individuals born without their cohort’s navigational abilities. These birds with “reversed compasses” often migrate irregularly during their first year of life.

These vagrants can show up anywhere, but there are a few tricks to looking for them. Watch the weather, and go birding a few days to a week after strong southwesterly winds. Seek out edge habitats, bodies of water, and potential sources of food— like thickets of late-season berries, or low and sheltered areas near coastlines where flying insects persist later into the fall.

The past few weeks have been a promising lead-up to western rarity season, with Cave Swallows already appearing on the South Shore, and a Say’s Phoebe seen in Barre in mid-October.

Right now, conditions look fairly promising—winds over the dry interior of the US are blowing strongly from the northwest, but they connect with two large cyclonic storms moving northeast. Following that, forecasters call for strong southwest winds. It will be interesting to see whether or not the upcoming storm system leaves any vagrants in its wake, and in all likelihood, it will.

 

 

Here are some species to stay on the lookout for:

  1. Cave Swallow: These small birds of the south-central US and Caribbean have begun to show up like clockwork. They arrive almost exclusively at coastal sites after strong pulses of southwest winds, and in recent years, there have been numerous annual sightings several birds at once. The phenomenon of Cave Swallows showing up in the Northeast is fairly new. Cave Swallows were extremely rare in Massachusetts before the last decade or so.
  1. Ash-throated Flycatcher: These also used to be much less frequent, but in recent years, have been showing up every 1-2 years at coastal sites. A couple have been seen a few miles inland at open, brushy sites like Drumlin Farm in Lincoln and Danehy Park in Cambridge, but with less regularity.
  1. Western Tanager: Roughly the same patterns as Ash-throated Flycatcher, but with more inland records.
  1. MacGillivray’s Warbler: One or several show up about every other year. They are mostly detected in farm fields and suburban thickets . Most sightings are from November, though a few exist from the Cape and South Coast regions in the early fall or late winter.
  1. Mountain Bluebird. These only show up every 3-5 years, having been most recently seen in MA at Turner’s Falls Airport from November 13-16, 2016.
  1. Townsend’s Solitaire: Almost annually, some solitaires arrive in November and linger until at least midwinter. In Massachusetts, most records are from Cape Ann and Cape Cod, although there are many inland records from Connecticut, Vermont and New Hampshire.

There are plenty of other species that show up well outside of their range in November, from the annual Western Kingbird to the exceptionally rare Common Ground-Dove. Will you be the next Massachusetts birder to find one?

Subscribe to Distraction Displays for more birding tips, news, and updates on Mass Audubon’s conservation activities.

Cities Need Bird-Friendly Buildings

Posted on September 21, 2018 by William Freedberg

Between 100 million and 1 billion birds die annually from collisions with windows. Glass windowpanes can reflect nearby trees, shrubs, and sky. Birds’ eyes aren’t able to distinguish clear reflections from the real thing, so they sometimes aim for a reflection and fly smack into a pane of glass.

Earlier this year, Mass Audubon’s advocacy team expressed concern about a plan to install an all-glass façade on a building facing Post Office Square in Boston. An island of green in downtown’s sea of concrete, Post Office Square is a locally important stopover site for migratory birds. A few plantings in the middle of a nearly treeless part of the city attracts a surprising diversity of species, and adding a wall of glass panels across from one side of the park increases the risk of collisions . The well-meaning developer wanted to add a perimeter garden and a green roof to the site, which ironically would increase window strikes by attracting birds to reflections of the greenery.

Luckily, when told about the risk the project posed for birds, this developer was willing to make the site safer. They are in the process of installing glass with non-reflective stripes, which will break up reflections of what’s outside and steer birds away from the windows. Many similar technologies exist to make windows visible obstacles to birds without interfering with peoples’ view—from glass incorporating ultraviolet patterns that only birds can see, to entire panes made of non-reflective material.

Post Office Square, an urban stopover site for migrating birds (Photo by Will Freedberg)

You Can Help!

Skyscrapers account for disproportionate numbers of bird deaths, but the number of single-story buildings in the US make them an equally important front for reducing window strikes. Every homeowner interested in conservation can take steps to make their homes safer for birds:

  1. Keeping window screens on year-round. This is a great option because it provides a visual barrier as well as soft, springy physical barrier to incoming birds.
  2. Purchase and apply a one-way, see-through film to your windows, which both cuts reflections for birds and blocks the view into your home from outside.
  3. Finally, any birdfeeders close to your house (within 15 feet) should be even closer to windows (less than 1.5 feet away). While this sounds weird, birds do slow down before perching, so any window collisions as a bird comes in to land at your feeder is unlikely to injure the bird.

 

 

 

 

 

 

 

References: Daniel Klem, 1990: Collisions Between Birds And Windows: Mortality And Prevention

 

How Do Pelagic Birds Find Fresh Water At Sea?

Posted on August 31, 2018 by William Freedberg

The short answer: they don’t.

Seabirds drink ocean water, and excrete the excess salt that would otherwise leave them dehydrated. Specialized glands, located above the beak and just under the eyes, filter salt ions from seabirds’ bloodstream. The glands also draw out just enough water to dissolve salt into a highly concentrated saline solution, which runs out through the bird’s nostrils.

If you’ve ever seen a gull standing on dry land, with fluid dripping down the tip of its beak… that’s because it’s expelling salt!

These glands can atrophy and stop working if not regularly used. Seabirds at zoos and wildlife rehabilitation clinics actually need to be kept in saltwater—if their glands stop pumping, the birds can experience salt poisoning when re-exposed to ocean water.

 

A Sooty Shearwater exhibits a typical “tubenose” beak structure: elongated nostrils through which salt is excreted. Photo © William Freedberg

 

Terrific Tubenoses

Birds in the family Procellariformes (which includes albatrosses, shearwaters, petrels and storm-petrels) excrete salt through one or two tubes that sit atop their beaks, giving the group the informal name of “tubenoses”. A common misconception among birders is that this tube is an organ used uniquely for excreting salt.

In fact, it’s not clear that these birds process salt any more efficiently than any other seabirds, like pelicans or marine ducks. Tubenoses’ beak structure might help them keep saline excretions from blowing into their eyes in high oceanic winds, but that’s probably not its primary function.

Recent evidence suggests that these tubes help channel airborne scents, contributing to tubenoses’ ability to sniff out plankton blooms on the open ocean. There’s also evidence that the nasal tubes of albatrosses contain pressure-sensing nerves, helping these birds find and navigate the rising air currents they use to stay aloft.

 

Seabirds Under Threat

Seabirds’ exquisitely fine-tuned sense of smell serves them poorly in oceans plagued by plastic pollution. It turns out that plastic, especially when covered in marine algae, smells just like the zooplankton seabirds love to eat.

While some seabirds that frequent Massachusetts waters are doing well (like Wilson’s Storm-Petrels and Cory’s Shearwaters) others are in serious trouble. And unlike some declining groups, pelagic birds’ absence flies largely under the radar of most land-bound naturalists. Among myriad dangers, entanglement in fishing gear, climate volatility, and invasive species drive seabird declines.

Help fight these threats by purchasing American-caught seafood—fishery regulations here favor seabirds more than in much of the world— and by reducing plastic waste.

The World’s Funniest Bird Sounds- And How They’re Made

Posted on August 24, 2018 by William Freedberg

Last month’ post about amazing bird sounds from Massachusetts was so popular, we decided to create a definitive ranking of the funniest bird vocalizations from around the world.

How do birds make so many sounds?

Birds have a vocal organ called a “syrinx” that mammals (and other vertebrates) lack. Different groups of birds have specialized syrinxes that can produce different sounds, but all of them allow for a wide variety of vocalizations.

Humans have a single set of vocal chords that sit in the windpipe, or trachea. Most birds’ syrinxes, on the other hand, are located where their trachea branches in two (towards each lung). This allows some songbirds, like thrushes, to regulate the air exiting each lung individually, creating two distinct notes at once. Other birds, like parrots, have a syrinx in their trachea—but with more moving parts than human vocal chords.

All syrinxes share this complexity. In addition to using membranes that vibrate to produce sound, the syrinx contains a network of muscles to “shape” air as it exits their lungs—sort of like how we use our lips to whistle, but with a few added degrees of complexity.

The contenders:

10. Screaming Piha


This group of Pihas from the Amazon sound… just plain rude.

 

9. Slate-colored Solitaire


Like the Veery in Massachusetts, these members of the thrush family give the forest soundscape an ethereal feel with their clear, echoing whistles. Click on 2:18 for the best part!

 

8. Andean Goose


These aren’t flatulent geese- that’s just their syringeal flutter.

 

7. Willow Ptarmigan


Ptarmigans sound cartoonish, and their clucking can resemble the sound of human speech.

 

6. Great Jacamar


Ambush predators of the rainforest mid-story, Jacamars can sit motionless for hours waiting for their butterfly prey to come within catching distance. Their nasal, drawn-out calls fade out towards the end, sounding almost lazy, and evoking the midday heat of tropical forests.

 

5. Short-tailed Shearwater


Shearwaters and petrels are often silent at sea, but clamorous at their burrows.

 

4. Capuchinbird


These birds are incredibly loud, and their voices can carry for miles. They’re known locally as the “calfbird” for their lowing, cow-like moans.

 

3. Laughing Kookaburra


A classic sound of the Australian bush at dawn, gregarious Kookaburras duet and countersing with each other frequently.

 

2. Imperial Snipe


This combination of cackles and what sounds like a landing spaceship is just about as weird as it gets. But the otherwordly humming and buzzing that accompanies the Snipe’s vocalization is created by air rushing past its wings as it displays– so the snipe only comes in at #2.

 

1. Horned Screamer


Screamers gulp like bitterns, honk like geese, and irritate residents of Amazonian South America with their dawn cacophanies like no other bird.

 

With such a wide range of sounds, it’s no wonder birdsong inspired so many human musicians—from Vivaldi’s 17th century goldfinch themes, to DJ Ben Mirin’s wildlife-inspired EDM.

What do you think about this (deeply subjective) ranking? Can you think of any birds that should have made the cut?

 

 

Tips For August Nighthawk-Spotting

Posted on August 8, 2018 by William Freedberg

Aerobats. Daredevils. Show-offs. The bounding, athletic flight the Common Nighthawk makes for an impressive spectacle in late summer twilight, when groups of these birds swoop to catch insects in midflight.

In the last two weeks of August into early September, these birds power across Massachusetts on hooked, falconlike wings. Nighthawks pause during migration to gather and feed near the edges of open fields, making them easy to observe on their way South.

Two Common Nighthawks streak through the sunset light in Cambridge, MA. Composite image by Will Freedberg.

Nighthawks are totally unrelated to hawks, a group with which they share very little. As members of the nightjar family, nighthawks look similar to the closely-related Whip-poor-will when perched on the ground. In the air, they appear totally unique, agilely swooping and diving in continuous flight.

While springtime brings modest numbers of nighthawks to New England, they show up in much greater numbers on their southbound migration. Nighthawks feed on flying ants, which hatch here en masse in late summer, to fatten up before making the long trip to South America. In spring, when insects are scarce, most nighthawks take a more direct route around Massachusetts to their breeding grounds.

Don’t miss the three-week window for seeing migrating nighthawks this year! Here are some tips for finding them.

 

Find a Field

Just before sunset, nighthawks often emerge around grasslands and big fields. Near Boston, nighthawk hotspots include Millennium Park in West Roxbury, Rock Meadow in Belmont, and Heard Conservation Land in Wayland. In the rest of the state, any open hilltop or good vantage point near a river will do!

 

Follow the Rivers

Nighthawks use river valleys to navigate. While any open field is apt to produce a nighthawk sighting at dusk in late August, rivers running North-South tend to concentrate nighthawks in impressive numbers. In the Connecticut River Valley, this can mean over a thousand birds streaming by over the course of the evening—although such a spectacle doesn’t happen every year.

 

Join a Program

Mass Audubon sanctuaries host nighthawk searches in every part of the state! Here are a few that are coming up:

 

Connecticut River Valley
August 22, 2018

Nighthawks and Chimney Swifts at Arcadia Wildlife Sanctuary

This program will begin with an indoor presentation about each bird before heading out to search the sky for nighthawks and swifts.

 

Western Massachusetts
August 24, 2018

Evening Nighthawk Watch at Canoe Meadows

Search the evening sky for migrating nighthawks at Canoe Meadows. With luck, you’ll be able to observe these beautiful aerial acrobats catching insects on the wing. This event is free.

 

Worcester Area
August 28, 2018:

Migration of the Common Nighthawk in Millbury

Learn about nighthawk adaptations, ecology, and how to look for feeding behavior, while witnessing their migration flight.

 

Boston Area
September 5, 2018:

Sudbury River Nighthawks with Drumlin Farm

Open vistas along the Sudbury River offer perfect vantage points from which to scan the sky for nighthawks. The group will explore the marsh, grassland and orchards for other fall migrants.

 

 

Conservation Success Stories: The Osprey

Posted on August 1, 2018 by William Freedberg

Ospreys are on the rebound after a troubled past. Despite a history of pesticide poisoning, persecution, and population declines, Ospreys have returned as one of the most abundant raptors of the coast. Today, the Osprey’s story stands as a testimony to the power of scientifically-informed environmental activism.

An Osprey stands watchfully on a snag over a marsh. Photo © William Freedberg 2015

DDT: A Silent Threat

Osprey numbers crashed dramatically following the widespread use of DDT, a pesticide deployed across America in the 1940s. While previous decades saw Ospreys hunted as “pests” and their wetland habitats drained for development, the introduction of DDT all but rang the death knell for the entire US Osprey population.

Nobody realized it at the time, but DDT builds up in animals’ body tissue, and persists in the environment years after being sprayed on farm fields. This spelled trouble for birds of prey: while DDT spraying rarely poisons adult birds to death, it destroys the structure of raptors’ eggshells, preventing them from reproducing.

As a result, Ospreys declined by over 90% between 1950 and 1970. When the now-famous environmentalist Rachel Carson finally named DDT as the culprit in her book Silent Spring, the discovery ignited a movement. A coalition of the National and Massachusetts Audubon societies, as well as local land trusts and nationwide advocacy groups, intervened on behalf of all species threatened by DDT. They sued the Environmental Protection Agency to ban the pesticide—and won.

A few decades later, Ospreys are almost back to their pre-DDT abundance.

A Place To Nest

The DDT ban eliminated a significant threat to Ospreys, but the bird didn’t immediately bounce back. Even in places with clean water and plenty of fish, Osprey numbers are naturally limited by the number of appropriate nest sites. They normally require a tall, dead tree at the edge of a marsh, but lacking standing trees in the open, they settle for utility poles or other problematic locations.

Artificial nest platforms are one solution. In addition to keeping Osprey nests away from telephone wires and buildings, nest platforms increase the number of Ospreys any wetland can support. With wetland edge habitats constantly losing ground to development, it’s critical to maximize the number of Osprey nesting in appropriate wetlands.

Mass Audubon Continues To Support Ospreys

Mass Audubon’s South Coast Osprey Project maintains about 100 Osprey nest platforms. The project also monitors and records data on the Osprey population, including banding and tagging several birds, and tracking their movements. The data never fails to yield exciting results— whether demonstrating Ospreys’ reliance on the spring herring migration for food, or revealing variability in Ospreys’ choice of wintering grounds (South Shore birds end up in places as far away from one another as Cuba and Bolivia).

If you love Ospreys as much as we do, consider sponsoring a nest platform!