Category Archives: Birds & Birding

Bald Eagle flying

When Pest Control Poisons Wildlife: Why It Happens and How to Help

(Disclaimer: the post below includes a photo of a dead bald eagle)

This week, Massachusetts passed a sad benchmark–the first documented case of a bald eagle death in the state from second-generation anticoagulant rodenticide (SGAR) poisoning.  

Or, in clearer terms: rat poison. 

Anticoagulant rodenticides kill rodents by preventing blood from clotting normally. But these poisons can have unintended victims when wildlife, like birds of prey, ingest them or eat prey that has consumed the bait. 

Second-generation anticoagulant rodenticides (SGARs) can be especially problematic since they don’t kill rodents immediately. Poisoned rodents can still live for a few days and consume more poisoned bait during that time, and the delay means they can ingest enough poison to kill a much larger animal. 

Photo: James B. Condon

Aren’t These Poisons Regulated?

Second-generation anticoagulants have been banned by the EPA from the consumer market, but licensed exterminators are still allowed to deploy them. Other rodenticides, called first-generation anticoagulant rodenticides and non-anticoagulant rodenticides, are still approved for residential consumer use if enclosed within a bait station. 

While this was the first confirmed case of an eagle death in the state as a result of SGARs, the issue of birds of prey becoming the unintended victims of these poisons is a growing problem. Nearly every raptor species is vulnerable to rodenticide poisoning. For example, one recent study found that 100% of tested red-tailed hawks at Tufts Wildlife Clinic had been exposed to anticoagulant rodenticides. Secondary poisoning has also been documented in species like foxes, bobcats, and coyotes.

What’s the Solution?

With rat populations on the rise, pest control measures continue to be necessary. But many poison-free options for preventing rodent problems exist. In addition to non-chemical traps, these include exclusion methods, like sealing up access points to buildings, and sanitation methods, like securing trash bins to reduce food sources.  

If the situation necessitates hiring a pest control company, choosing one that uses Integrated Pest Management (IPM) can also make a big impact in reducing widespread pesticide use. IPM relies on a series of pest management evaluations, and its strategies can include trapping, sealing up entry holes in foundations, walls, and roofs, and removing or trimming vegetation that obscures the ground.  

We also need laws to regulate the pesticides that do continue to be used. In California, legislation has passed prohibiting the use of SGARs until state agencies can reevaluate what long-term restrictions are needed to avoid impacts to nontarget wildlife.  

Here in Massachusetts, An Act relative to pesticides would better regulate the use of SGARs, in turn reducing their impacts on birds of prey and other wildlife. The bill would: 

  • Increase use of IPM strategies in Massachusetts 
  • Educate consumers about the benefits of IPM and impacts of SGARs 
  • Require digitization of pesticide use forms, making them more accessible and searchable 

You Can Help Stop Wildlife from Being Poisoned

Ask your state legislators to co-sponsor An Act relative to pesticides today! The more co-sponsors a bill has, the more support it has behind it and the better chance it has of passing. 

By improving our approaches to pest management, we can reduce the need for rodenticides at their source and help our wildlife thrive. 

Bald Eagle Flying © David Morris
Bald Eagle © David Morris

Protect Birds by Addressing Climate Change

When Harriet Lawrence Hemenway and Minna B. Hall founded Mass Audubon in 1896, they were committed to ending the cruel practice of killing birds for fashion. Since then, Mass Audubon has continued its dedication to protecting birds through the threats they’ve faced over the decades – and now that means addressing climate change

North, North, and Away 

Both plants and animals live in predictable environments, and one of the most important parts in defining these environments is their temperatures. But climate change is causing temperatures to increase world-wide. As Massachusetts gets warmer, the plants and insects that comprise these environments are shifting northward – and we’re seeing birds follow them away from the Commonwealth. 

Higher temperatures also provide a suitable environment for the spread of invasive pest and plant species – both of which reduce healthy Northern hardwoods forested habitat.  

49% of the Massachusetts’ breeding forest bird species we studied are highly vulnerable. 

Black-throated Blue Warbler © Terri Nickerson

The Commonwealth’s Black-throated Blue Warbler and Yellow-rumped Warbler are expected to decline as the Northern hardwood trees they call home are overtaken by more heat tolerant species. Ruffed Grouse, Yellow-bellied Sapsuckers, and Wood Thrushes are also expected to be vulnerable to the reduction of Northern hardwoods forested habitats as a result of this shift in dominant tree species. 

Changing Seasons 

Our seasons are changing, impacting bird food sources and nesting behaviors. With milder, shorter winters and earlier springs (among other shifts) – the environmental cues that typically trigger breeding or nesting behavior and the emergence of food are thrown out of whack. 

66% of the Massachusetts breeding, long-distance migrants we studied are highly or likely vulnerable.  

Tree Swallow in nest box.

Migratory species, like Tree Swallows, can only make minor modifications to their migration schedules to coincide with the shifting peak abundance of their food. The dissonance between migration and breeding schedules and shifting seasons can adversely affect breeding birds— especially if available food sources are insufficient to raise their young. 

Rising Sea Levels 

With tides creeping farther up our shores, sea level rise is swallowing important marsh and beach-nesting habitat of coastal bird species. 

56% of the Massachusetts’ breeding, coastal-nesting species we studied are highly vulnerable. 

Piping Plover and chicks © Lia Vito

These, often already threatened, species now contend with the effects of sea level rise. Least Terns, Piping Plovers, and Saltmarsh Sparrows nest in habitats that are slowly being overtaken by this climate impact in addition to the increasing frequency and severity of storms. 

We Can Make a Difference 

Let’s come together to protect birds by working to solve climate change in two ways: by adapting to climate change (withstanding its current impacts) and mitigating climate change (reducing our greenhouse gas emissions and removing them from the atmosphere). Visit massaudubon.org/climate for how you can start doing both. 

red-winged blackbird

The First Sounds of Spring

Red-winged Blackbird © Rachel Bellenoit

Some resident birds start singing their spring songs in late February and early March like clockwork, no matter what the weather is doing.

Even when winter keeps its grip on Massachusetts with snow and freezing temperatures, these birds mark the lengthening days with songs to attract mates, define their territories, and prepare for breeding season.

Early songsters respond to the amount of time between sunrise and sunset—called the photoperiod—and shift their behavior towards spring patterns accordingly.

Here are some of the earliest sounds that prove spring is just around the corner.

Black-capped Chickadees whistle a thin, pleasant “fee-bee!”:

Northern Cardinals give high, piping warbles from exposed perches:

Mourning Doves make low, resonant coos throughout the day:

A week or two after these birds start sounding off, the earliest short-distance migrants arrive from the southeast part of North America: Common Grackles and Red-winged Blackbirds.

Blackbirds’ jangling, metallic song is most often heard in marshes and wetlands:

Grackles give a chorus of creaks and harsh “chack!” notes in large, transient flocks:

The arrival of spring accelerates after the first few migrants arrive, with skunk cabbage poking through the soil in wetlands and more birds like Ruby-crowned Kinglets to Yellow-rumped Warblers showing up.

All of these species are out and singing by the second week of March. Which ones have you been hearing so far this year?

Birders Meeting Goes Virtual

Every March since 1992, birders from around New England have come together to attend Mass Audubon’s annual Birders Meeting. This year’s event, which will take place virtually over four days, is focusing on “The Bird Next Door: Birding Your Patch.”

Ruby-throated Hummingbird © Christine St. Andre

What is Patch Birding?

Simply put, “patch birding” means focusing your efforts on one local area to develop a deep knowledge of the place and its birds. Your patch can be your yard, your neighborhood, the swamp down the street, your apartment balcony, or any place you visit regularly.

Patch birding is taking off because it helps us focus closely and see birds in a new light. It can also lead to exciting discoveries, from easily-overlooked hotspots to unreported patterns in species migrations and distribution. Patch birding also reinforces the value of parks and greenspaces, and, perhaps most importantly, reduces climate-altering CO2 emissions from travel.

Schedule and Speakers

The Birder’s Meeting will take place March 7, 8, 14, & 15. You can choose to sign up for individual sessions or the whole series. 

Sunday, March 7 • 7:00-8:30 pm ET

125 Years of Conservation with David O’Neill and The Value of Birding Your Patch with Heather Wolf, Cornell Lab of Ornithology

Mass Audubon President David O’Neill will kick off this year’s Birders Meeting with a short presentation on Mass Audubon’s impressive history in conservation and his vision for the organization going forward. Learn more about our 125th >

Join birder, author, and photographer Heather Wolf as she shares her ongoing urban patch birding adventure under the Brooklyn Bridge in New York City, where she has documented over 170 bird species over the years.


Monday, March 8 • 7:30-8:30 pm ET

A Sense of Place with Susannah Lerman, USDA Forest Service Northern Research Station

For many of us, we had our first experiences with the natural world in our backyards and neighborhood parks. These natural history sparks often ignite a life-long appreciation for birds and other wildlife. Susannah Lerman will present research on how aesthetics (e.g., color and bird song) influence human-wildlife interactions and how public interest of backyard birds compares with ecological dynamics in residential landscapes.


Sunday, March 14 • 7:30-8:30 pm ET

Nature’s Best Hope with Doug Tallamy, University of Delaware

Recent headlines about global insect declines and three billion fewer birds in North America are a bleak reality check about how ineffective our current landscape designs have been at sustaining the plants and animals that sustain us. Author Doug Tallamy will discuss simple steps that each of us can—and must—take to reverse declining biodiversity and will explain why we, ourselves, are nature’s best hope.


Monday, March 15 • 12:00-1:00 pm ET

Birding at the Speed of Slow with Scott Edwards, Museum of Comparative Zoology at Harvard University

How we bird, and how we move through the landscape, is as important as what we bird. Scott Edwards will share how birding a local patch repeatedly or moving slowly through seasons and soundscapes allows us to see details of song, behavior and migration that reveal birds’ annual cycles—when and how their lives change over time.

Skyline copyright Michael Mondville

One Way Light Pollution Impacts Birds

Skyline copyright Michael Mondville
Boston’s bright lights create a hazy glow on the horizon that can be seen for miles. Photo © Michael Mondville

Migrating birds are attracted to artificial light at night, and ornithologists are just beginning to understand how that affects their survival.

Recent studies show that the diffuse glow of entire cities can draw migrating birds towards them—and away from more suitable habitat.

There are already hundreds of records of mesmerized birds fluttering around single, isolated sources of bright light— from thousands of migrants trapped in the beams of mile-high searchlights in New York City, to dozens of warblers gathering at the windows of lighthouses.

But until recently, there was limited evidence for how light pollution across an entire region affects where migrants rest and feed.

Radar studies show “clouds” of birds near cities 

To test if birds gather disproportionately in brightly-lit cities, migration ecologists looked to doppler radar data. This is the same radar used to create weather forecasts across the country. Doppler radar reveals the density of particles in the air, whether it’s rain, birds, or aircraft, so it’s useful for remotely observing which areas migrating birds are using the most.

Naturalists might expect that migratory birds gravitate towards undeveloped areas, just as most do when they aren’t migrating. But this isn’t necessarily true, according to a team led by scientists from the University of Delaware.

In fact, radar signals consistently show more migrants pausing within a couple of miles of brightly-lit areas than anywhere else within around 30 miles. Migrant density peaks again 50-60 miles away, where the glow of lights on the horizon is dimmer or invisible.

These graphs show the density of migrating birds relative to major sources of light pollution like cities in spring (left) and fall (right) migration. Source: Cohen et al. (2020) (axis labels added).

This suggests that artificial light from cities is drawing in birds from greater distances than once believed. The authors of the study write that this pattern risks “impeding [birds’] selection for extensive forest habitat.” 

They go on to caution that “high‐quality stopover habitat is critical to successful migration, and hindrances during migration can decrease fitness.”

Prioritizing Urban Greenspaces for Birds

Migratory birds’ attraction to artificial light may be one reason behind the surprisingly excellent birding at greenspaces in cities—something birders have known about for a long time, but struggled to fully explain.

A canopy of trees meets Boston’s skyline, as seen from Mt. Auburn Cemetery in Watertown. Source: Wikimedia commons

Take Mount Auburn Cemetery, for example: it’s arguably the most famous site in the Northeast to see big numbers of warblers in spring. New York City’s Central Park, too, offers excellent birding that can rival—or outmatch—spring migration in intact forests.

But despite their attraction to the bright glow of cities, birds face increased hazards in urban environments. Most migratory birds feed exclusively on insects, which are harder to come by in cities, and urban ecosystems host more predators per square mile than other habitats.

Modifications as simple as planting native species, reducing insecticides, adding understory and mid-story habitat, or controlling predators could give migrants a much-needed boost at these sites. As long as light pollution continues to be an issue, improving urban habitat and reducing hazards remains important work.