Category Archives: Conservation Issues

Help Us Learn About Bird-Window Strikes Downtown

Calling all citizen scientists near Boston!

Mass Audubon needs your help monitoring an underappreciated threat to migratory birds: window collisions. We’re looking for volunteers to collect data on bird-building collisions and rescue birds that survive a strike.

A Black-throated Green Warbler that died on migration from a window collision.

The Problem

Window collisions are a surprisingly significant source of bird mortality in the US, causing several hundred million casualties annually.

Birds struggle to distinguish reflections from reality, and often strike glass windows that reflect the sky or nearby greenery. City lights also confuse night-migrating birds, which use the stars to navigate, and which often land near sources of light pollution. Many window strikes occur as birds try to re-orient in the morning, after being drawn in to an unfamiliar concrete jungle.

How to Help

The Avian Collision Team (ACT) is a new volunteer initiative to get as much data as we can about building strikes in Boston. We want to understand the scale of the problem in Boston, where the trouble spots are, and which species are most affected.

The program runs from April 13–June 4. Volunteers need to sign up for 1-4 weekly shifts, Saturday–Tuesday, from 8 am to around 9 am.

We are looking for two kinds of volunteers:

1. Monitoring volunteers who will walk predetermined routes to collect deceased specimens, fill out data sheets, and occasionally rescue live birds.

2. Transport volunteers who can pick up specimens from monitors and bring them to a collection site at Harvard. Drivers will also bring occasional injured, live birds to Tufts Wildlife Clinic in Westborough as needed.

Similar programs have shown that in parts of some cities, there are practically no casualties. In others, certain buildings can kill a dozen birds a day during peak migration. Scientists have developed guidelines for what makes buildings especially dangerous to migrating birds, but they’re still pretty rough. The best way to know where and to what extent there’s a problem in Boston… is to check! 

If this sounds interesting, sign up here!

Rising Seas are Flooding Saltmarsh Sparrow Nests. Can They Adapt?

A recent study showed that Saltmarsh Sparrows choose nest sites based on past experiences. If a pair’s nest floods, for example, they’ll build their next on higher ground.

While this behavior might seem to show resilience to rising seas and climate change, the authors note that populations have still declined by over 75% since the 1980s.

In fact, nesting further away from the water a risky proposition for Saltmarsh Sparrows, and flooding is not the only threat to their nests. As with any species threatened by climate change, what appears to be a successful adaptation to environmental change often turns out to have unforeseen repercussions for the species.

A Saltmarsh Sparrow in the cordgrass (Spartina sp.) of a New England Marsh. Photo by Shawn Carey.

Caught Between a Fox and a Hard Place

Nesting further from the high-tide mark comes with trade-offs. Nests over drier ground are most vulnerable to predators, which are the second-greatest cause of nest failure in Saltmarsh Sparrows aside from flooding. Small carnivores like raccoons, foxes, and even snakes have been spotted feeding on Saltmarsh Sparrow chicks in nests far from the water’s edge.

Ticks, isopods, and other parasites also prefer drier nests. Some tidal flooding deters invertebrate pests, and may actually contribute to nestling survival as long as the nest isn’t completely inundated.

Nests are most likely to be successful in a narrow band near the high-tide mark where they are safe from predators, parasites, and flooding. Researchers found that Saltmarsh Sparrows that lost their nests to predators would re-nest closer to the waters’ edge, just as birds with flooded nests would move to higher ground. But as increasingly severe storms now regularly push spring tides past their normal height, they wash over what was once the “sweet spot” between safety from predators and safety from flooding.

So, even though Saltmarsh Sparrows adjust their behavior to manage risks, they’re still only resilient to mild disruptions like steady and gradual sea level rise. Regularly-occurring extreme floods, coupled with

Saltmarsh Sparrows are in Trouble

Climate threats to Saltmarsh Sparrows are borne out by the data. Their population is currently around 30,000 birds– half of what it was in 2010, and a shadow of the original population of 250,000. They continue to decline at around 9% annually nationwide, but in Massachusetts, careful management of saltmarshes has kept their numbers comparatively stable. 

Climate change is not the only issue facing Saltmarsh Sparrows. Over 1/3 of Massachusetts’ coastal wetlands have been developed. Dikes, railways, and other infrastructure disrupts the drainage of many remaining saltmarshes, raising the threshold for flooding but causing them to retain floodwaters for longer periods.

Mass Audubon continues to monitor Saltmarsh Sparrows in Massachusetts and advocate for the species, including submitting a proposal to list them as an Endangered species at the state level in 2017.

For tips on combating climate change, find out how to reduce your carbon footprint. For more information on Saltmarsh Sparrows, feel free to ask us a question in the comments!


Bald Eagle via USFWS

Rat Poison Is Killing Birds Of Prey, And People Are Finally Paying Attention

Note: this post contains an image of a dead Bald Eagle that some readers may find graphic.

Most rat poisons kill more than rats—they also pose a fatal threat to birds of prey. This topic recently made the news after a Bald Eagle on Cape Cod died of what appears to be rodenticide poisoning. The tragic story was picked up by several newspapers, and went locally viral on facebook.

This issue should not only get attention when a culturally iconic species like a Bald Eagle dies. Nearly every raptor species is vulnerable to rodenticide poisoning, from Eastern Screech-Owls to Red-tailed Hawks.

In fact, rodenticide poisoning is shockingly widespread. In one study, 86% of all raptors at a Massachusetts wildlife hospital tested positive for exposure to rat poison.

Second-generation rodenticides: the worst of a bad bunch

The EPA recently banned a class of rat poisons called second-generation anticoagulants from the consumer market, but licensed exterminators are still allowed to deploy them. The ban came about because of the 10,000 children annually admitted to emergency rooms for rat poison exposure. The ban certainly helps limit accidental ingestion by humans, but unfortunately doesn’t do much to prevent birds from eating poisoned rodents.

Second-generation anticoagulants don’t kill rodents immediately. While these rodenticides can kill rats with a single dose (which is why many consumers prefer them), poisoned rats can still live for a few days and continue eating poisoned bait. This delay means that rats can ingest enough poison to kill a much larger animal by the time they finally succumb. While any rodenticide can kill a raptor, second-generation anticoagulants are the most dangerous.

The aforementioned Bald Eagle on Cape Cod likely fell victim to this class of rodenticide. While vets at the Cape Wildlife Center are still waiting for test results to come back, the eagle was bleeding heavily, and its blood failed to form scabs or clots—a nearly sure sign of anticoagulant poisoning.

This Bald Eagle was admitted to Cape Wildlife Center, but sadly didn’t make it. Photo courtesy of Cape Wildlife Center.

Rats are a human-made problem

Native to Eurasia, brown rats have colonized much of the globe and become the most common urban rodent worldwide. These rats were among the first human-assisted invasive species, living aboard ships and rapidly spreading to other continents as early as the 15th century, much to the detriment of countless sensitive ecosystems. Rats and other rodents especially wreak havoc on species found only on small islands, and have driven several seabird species to extinction.

Rat populations are on the rise, and towns are struggling to keep up (the town of Belmont even had to close a city park over a recent rat infestation). Rodent control is sometimes critical to the health of a city or an ecosystem—so what are some poison-free ways to prevent or control rodent problems?

(Don’t) pick your poison

  • Prevention is the best cure for rodent problems. Rodent infestations only occur when there’s an easy source of food. Make sure your trash cans are scavenger-proof, cover vegetable gardens with net or wire, attach tree guards to the trunks of fruit trees.
  • Limit access to shelter and hiding places that appeal to rodents. Seal up holes in your attic, basement, crawl spaces, and shed, and remove tree limbs within three feet of your roof.
  • Consider alternatives to poison. The Tufts Wildlife Clininc points out, “People often believe poisons are more humane than snap traps, but an animal bleeding to death is neither quick nor especially humane.”
  • If a rodent problem has gotten out of hand and you choose to use an exterminator, try to pick one that practices “integrated pest management”— a multi-pronged approach that avoids chemical control methods.
  • Finally, call your town or city hall and ask how the local government addresses rodent control. Suggest eliminating rat poison if it hasn’t been done already!

 

Cities Need Bird-Friendly Buildings

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