Study Measures Light’s Dramatic Impact on Bird Migration

Artificial light at night disorients migrating birds

2017 Tribute in Light © Kyle Horton

2017 Tribute in Light © Kyle Horton


Billions of birds undertake migratory journeys each spring and fall. Most of these spectacular movements go unseen, occurring under the cover of darkness. A new study published in the Proceedings of the National Academy of Sciences provides some of the most compelling evidence yet that artificial light at night causes radical changes in the behaviors of migrating birds.


“We found that migrating birds gather in large numbers because they’re attracted to the light,” says Benjamin Van Doren of Oxford University, a lead author of the study. “They slow down, start circling, and call more frequently. They end up burning energy without making any progress and risk colliding with nearby buildings or being caught by predators.”


NYC Audubon collaborated with scientists from the University of Oxford and the Cornell Lab of Ornithology to study migrant bird behavior over seven years in a truly unique setting—Tribute in Light in New York City, held to commemorate the September 11, 2001 terrorist attack. Two beams of light–each with 44 xenon bulbs of 7,000 watts—rise into the night sky, mirroring the twin towers of the World Trade Center where nearly 3,000 lives were lost.


“This was a rare opportunity to witness the impact of powerful ground-based lights on nocturnally migrating birds,” says co-lead author Kyle Horton, now with the Cornell Lab, but working at the University of Oklahoma during the study. “This analysis would not have been possible without the help of tribute organizers.”


Well before the results of the study highlighted the effects of the installation, New York City Audubon reached out to the original tribute organizers, the Municipal Art Society, to let them know about the impacts of artificial light on migratory birds. In 2002, the two organizations worked together to develop a protocol to save the affected birds. The tribute lights are turned off for approximately 20 minutes when more than 1,000 birds are seen circling in the beams or flying dangerously low with frequent calling. The National September 11 Memorial & Museum, which took over as tribute organizers in 2012, continued this practice.


These brief interludes of darkness during the nightlong tribute provided a unique opportunity for the scientists to quantify changes in bird behavior in several ways during the alternating periods of light and darkness.


“We had more than 20 wonderful volunteers on the ground counting birds to confirm what was happening in the beams,” says co-author Andrew Farnsworth at the Cornell Lab. “We also used remote sensing tools, including data from local National Weather Service radars, to understand the density and movements of the birdsAcoustic monitors recorded call notes and captured the vocal behavior of birds in the beams. And we ran computer simulations to try to better understand the dynamics of the patterns we were observing.”


Images above were taken 20 minutes apart during the 2015 Tribute in Light and show concentrations of birds on radar with light beams turned off (left) and turned on (right). Figure adapted from "High-intensity urban light installation dramatically alters nocturnal bird migration" in Proceedings of the National Academy of Sciences, September 2017.

Images above were taken 20 minutes apart during the 2015 Tribute in Light and show concentrations of birds on radar with light beams turned off (left) and turned on (right). Figure adapted from "High-intensity urban light installation dramatically alters nocturnal bird migration" in Proceedings of the National Academy of Sciences, September 2017.


When the tribute was illuminated, the study’s authors found that densities of birds over lower Manhattan could reach 60 to 150 times the number that would typically be found in the area at that time. The concentrating effects of the intense light on the birds reached as high as four kilometers. The impact on birds was consistent even on clear nights. Many previous studies focused on the dangers posed by artificial light on nights with poor visibility. When the light beams were turned off, the birds dispersed within minutes to continue their migrations.


Although Tribute in Light provided a way to measure a specific instance of light attraction, bright nighttime lighting poses problems for birds, even in rural areas. The study’s authors point out that one solution is relatively simple.


“We recommend building lights be turned off for as much of the night as possible, but at least from midnight to dawn during migration season,” says study co-author Dr. Susan Elbin of New York City Audubon. “This is true for areas around homes as well as other brightly-lit areas such as sports stadiums, construction sites, offshore oil rigs, and large buildings. Migrating is already hard enough for birds without this added danger from artificial light at night.”


This study was conducted with support from the National Science Foundation, Leon Levy Foundation, Marshall Aid Commemoration Commission, Cornell Lab of Ornithology Rose Postdoctoral Fellowship, and NASA. 


Tribute in Light Monitoring 2017

Tribute in Light 2017 © Sean Sime

Tribute in Light 2017 © Sean Sime

Every year on September 11, two beams of light illuminate the sky over Manhattan, reminding New Yorkers and the nation to pause in remembrance of those who lost their lives on 9/11/2001. New York City Audubon has monitored this important and touching tribute since 2002 to ensure it is safe for migrating birds. The beams, created using 88 7,000-watt xenon spotlight bulbs, can attract large numbers of night-migrating birds in some years. Once in the powerful beams the birds can become “trapped” and circle the lights, putting them at risk of exhaustion, disorientation, and injury. If a critical mass of birds is spotted circling at any point throughout the night, NYC Audubon works in partnership with the National September 11 Memorial & Museum and Michael Ahern Production Services to turn off the lights for roughly 20 minutes, which allows the birds to disperse.


NYC Audubon staff, board members, and 35 volunteers worked together in small teams to count birds for the 10-hour duration of the tribute. Our volunteers logged a collective 137 hours of monitoring!

Volunteers Monitoring the Tribute in Light for Birds © Sean Sime

Volunteers Monitoring the Tribute in Light for Birds © Sean Sime

This year we were able to station additional observers adjacent to and 28 stories above the tribute monitoring site thanks to our friends at the Battery Rooftop Garden. This new vantage point allowed us to validate the counts taken at the monitoring site below and observe the birds from a different angle.


Peak migration activity typically occurs around midnight, so we were surprised to see the number of birds quickly grow at 9pm. By 9:40pm, the birds were flying low enough that their night-flight calls were audible.

Birds Trapped in the Tribute in Light

Birds Trapped in the Tribute in Light 2017

The lights were turned off at 9:49pm to allow the birds to disperse. When we counted over 1,000 birds at 10:55pm, the lights were shut off for a second time. The lights were switched off for a third and final time when low-flying birds became a problem at 12:30am.


We confirmed in each instance using radar that the birds had left the area before the lights were turned on again. All of us at the tribute breathed a sigh of relief when bird numbers dwindled after 1am and the birds that were present appeared to pass through the beams without becoming trapped. The lights remained on until 6am.


We observed many of the species that we have become accustomed to seeing in the beams, such as black-and-white warblers, northern parulas, Baltimore orioles, and American redstarts. There were also some more notable observations, including a hunting American kestrel, chimney swifts, yellow-billed cuckoos, a hummingbird, and a downy woodpecker that landed on the ledge of a nearby building.


Predaceous Diving Beetle Seen at Tribute in Light 2017

Predaceous Diving Beetle Seen at Tribute in Light 2017

In addition to monitoring birds, we monitored bats for the second year in a row. We also added an arthropod collection component. Andrew Farnsworth and his team from Cornell joined us on the roof to record night-flight calls and monitor the birds with radar. Among the insects collected this year were a praying mantid, numerous lady beetles, and predaceous diving beetles (pictured). We also saw and recorded the echolocation calls of several eastern red bats that were taking advantage of the insects congregated in the lights.


Be sure to check out NYC Audubon’s Facebook page or our Twitter page for more photos and video from the event. To learn more about the work NYC Audubon does to protect migrating birds, visit our Project Safe Flight page. New York City Audubon’s Project Safe Flight program is made possible by the leadership support of the Leon Levy Foundation.


-Kaitlyn Parkins, Conservation Biologist


2017 Horseshoe Crab Monitoring and Tagging Recap

Horseshoe Crabs Spawning at Plumb Beach © Jennifer Kepler

Horseshoe Crabs Spawning at Plumb Beach © Jennifer Kepler

Another great horseshoe crab monitoring season has come and gone. It was quite an incredible year for horseshoe crabs in Jamaica Bay, with huge numbers of spawning horseshoe crabs at our four sites: Plumb Beach East and West, Big Egg Marsh, and Dead Horse Bay. While numbers are still preliminary, peak spawning appears to have taken place in the beginning of June. On June 11, we had 351 crabs at Plumb Beach East (in our quadrat samples), 59 at Plumb Beach West (in quadrat samples), and 1,313 at Dead Horse Bay (total count). Big Egg peaked slightly earlier, with 284 crabs in quadrat samples on May 27. While Big Egg’s numbers were down slightly from last year, overall numbers and spawning densities increased at all the other sites.


This was our ninth year collecting data on horseshoe crabs, an important food source for shorebirds like the threatened red knot, in Jamaica Bay. Our horseshoe crab monitoring and tagging efforts are part of a larger project run by the New York State Department of Environmental Conservation and Cornell University Cooperative Extension.


Our friends from National Park Service, who monitor horseshoe crabs at Great Kills in Staten Island, had an amazing year as well. They reported finding over a thousand crabs in just one night­—more than they’d seen in an entire season in some previous years.


With the help of a record 206 volunteers, including groups from Patagonia, Metropolitan Society of Natural Historians, Atlas Obscura, and the Trinity School, we tagged 800 horseshoe crabs in Jamaica Bay over the course of 12 nights this summer. We learned that 70 of those tagged crabs were resighted later in the season, almost always at the same beach where they were originally tagged. Every year shows us how important these locations are for spawning crabs that use the same beach repeatedly over the course of two months—and continue to come back year after year.


Of the 17 horseshoe crabs tagged at Plumb Beach West that were seen again, seven of them were resighted at Plumb Beach East. While this is still technically the same beach, it is interesting to learn that the crabs moved within this site during spawning season from the less populated west end to the more populated east end. No crabs tagged at the Plumb Beach East moved to Plumb Beach West.


Horseshoe Crab with Tag # 366741 © Debra Kriensky

Horseshoe Crab with Tag # 366741 © Debra Kriensky

We also resighted 20 horseshoe crabs tagged by our program in earlier years. Eight of them were tagged by us in 2016, seven in 2015, four in 2014, and one in 2013. There were also a handful of tags resighted in Jamaica Bay that were not part of our program; we’re anxiously waiting to hear where and when they were deployed.


Thank you to all of our volunteers who came out and helped with monitoring efforts this year. We of course couldn’t do this without the help of our outstanding site coordinators: Phil Cusimano, Christine Nealy, Ann Seligman, and Dottie Werkmeister. These dedicated individuals put a tremendous amount of time into making each survey go smoothly. We also want to thank National Fish and Wildlife Foundation’s Five Star and Urban Waters restoration program, Bank of America, FedEx, Patagonia, Williams Companies, and Investors Bank for their support of this year’s monitoring.


We are already looking forward to next year, which will be our 10th year tracking these amazing and important creatures!


-Debra Kriensky, Conservation Biologist


Recapping the 117th Central Park Christmas Bird Count

Central Park Morning Fog, 12/18/16 © Meryl Greenblatt

Central Park Morning Fog, 12/18/16 © Meryl Greenblatt

The 2016 New Jersey Lower Hudson (NJLH) annual Christmas Bird Count took place on Sunday, December 18, and results are flying in! Although the morning’s forecast called for heavy rain, we only experienced a light drizzle and some morning fog before it settled into a nice, mild winter day. The NJLH Count Circle is centered right in the Hudson River and includes Manhattan, Bergen and Hudson counties in New Jersey, and parts of Queens.



Hairy Woodpecker at 2016 Central Park Christmas Bird Count © Elaine Silber

Hairy Woodpecker at 2016 Central Park Christmas Bird Count © Elaine Silber

New York City Audubon organized the 117th annual Count in Central Park along with our partners from NYC Parks, Urban Park Rangers, and Central Park Conservancy. Altogether, 6,342 birds of 59 species were counted throughout the Park by over 75 participants. Highlights (bolded below) were American wigeon and Iceland gull on the Reservoir, a common yellowthroat east of the Pond, a killdeer in the North Meadow (possibly a new bird for the count!), and a northern pintail on the Pond. Some misses were red-breasted nuthatch, cedar waxwing, and brown thrasher, though some excellent birders did report brown thrasher and red-breasted nuthatches during Count Week, which includes the three days prior and three days following the official Count. Also reported in Central Park during Count Week were snow goose (flying over), red-shouldered hawk, long-eared owl, black-throated blue warbler, hermit thrush, and green-winged teal.



Canada goose – 125
mute swan – 1
wood duck – 6
gadwall – 2
American wigeon – 1
American black duck – 4
mallard – 445
northern shoveler – 113
northern pintail – 1
bufflehead – 9
hooded merganser – 8
ruddy duck – 156
pied-billed grebe – 2
double-crested cormorant – 1
great blue heron – 1
sharp-shinned hawk – 2
Cooper’s hawk – 7
red-tailed hawk – 16
American kestrel – 1
peregrine falcon – 1
American coot – 10
killdeer – 1
ring-billed gull – 512
Iceland gull – 1
herring gull – 149
great black-backed gull – 54
rock pigeon – 406
mourning dove – 85
belted kingfisher – 1
red-bellied woodpecker – 44
yellow-bellied sapsucker – 20
downy woodpecker – 22
hairy woodpecker – 2
northern flicker – 4
blue jay – 204
American crow – 19
black-capped chickadee – 48
tufted titmouse – 236
white-breasted nuthatch – 78
brown creeper – 3
Carolina wren – 3
golden-crowned kinglet – 1
ruby-crowned kinglet – 2
American robin – 239
gray catbird – 1
northern mockingbird – 13
European starling – 544
common yellowthroat – 1
fox sparrow – 17
dark-eyed junco – 73
white-throated sparrow – 1301
song sparrow – 13
swamp sparrow – 2
eastern towhee – 1
northern cardinal – 87
common grackle – 119
house finch – 3
American goldfinch – 20
house sparrow – 1099

In addition to the Central Park Count, there were also Counts in New Jersey, Randall’s Island, Inwood Hill, Riverside Park, Harlem, Bryant Park, Madison Square Park, Stuyvesant Town, East River Park, lower Manhattan, and for the first time, a feeder in Sunnyside, Queens! There was also a Count that took place on Governors Island to see if any additional species could be added to the Island’s list.



So far we’ve heard word of Baltimore orioles in various locations, a Lincoln’s sparrow in Bryant Park, and several exciting finds in New Jersey like a glaucous gull, red-headed woodpecker, Lapland longspur, seaside sparrow, and many more. Unfortunately, it seems the western tanager of City Hall Park departed just before the start of Count Week (perhaps to Queens, where one was counted during their count!). Final results for the entire NJLH Count Circle will be available soon on our website.



A huge thank you to those who participated in any of the NYC Counts this year, especially those who led and organized counts throughout the City!

CBC 2016 Central Park Southeast Team © Lynn Hertzog

CBC 2016 Central Park Southeast Team © Lynn Hertzog

-Debra Kriensky, Conservation Biologist



Getting To Know the Birds of Greenpoint, Brooklyn

Conservation Biologist Debra Kriensky reports on our work planting an “Urban Oasis” in industrial Greenpoint to provide much-needed stopover habitat for migratory birds as well as our citizen science outreach efforts to engage the Greenpoint community and learn more about the birds in the area:


Beginning in 2014, NYC Audubon received a grant from the Greenpoint Community Environmental Fund (GCEF) to install a 0.25-acre native plant garden in McGolrick Park in Greenpoint, Brooklyn. The area surrounding the park is largely urban, industrial, and relatively lacking in green space, making it an important resource for migrating and breeding birds in the area. Our aim was to improve the quality of this stopover habitat by planting a host of native plants that would appeal to not just birds, but to bees, butterflies, and other pollinators as well. We called our garden the “Urban Oasis”.


The Urban Oasis in June, with many native plants in bloom

The Urban Oasis in June, with many native plants in bloom

While we knew it was likely that many birds were migrating through Greenpoint and possibly breeding there, there was very little information about what birds could be found in McGolrick Park when we started planting the Urban Oasis in 2014. A search on the public online database eBird showed no reported bird sightings in the park–and only a handful of sightings in the entire Greenpoint area. In 2015, eleven species were recorded in the park by NYC Audubon and others after we completed the Urban Oasis, but we knew this number did not truly represent the diversity of birds we believed were present.


In 2016, NYC Audubon received an additional grant from GCEF to conduct six citizen science bird surveys throughout the year. The grant’s goal: to increase knowledge about what birds could be found in the park and when, and to encourage local Greenpoint residents to look for and report sightings of birds in the park and the neighborhood in general.


Black-throated green warbler seen in September during fall migration

Black-throated green warbler seen in September during fall migration

We held two citizen science surveys during spring migration, two during the summer breeding season, and two during fall migration. Local residents of Greenpoint were invited to join the surveys, and all results were put on the eBird database. We also held a free nature walk in September for local residents to learn more about the native plants in the Urban Oasis and park, as well as their benefits to wildlife.


All in all, our volunteers observed 34 species throughout the year. 19 of these species had not previously been recorded in the park, such as blackpoll warblers, cedar waxwings, and scarlet tanagers. NYC Audubon staff also took note of any conspicuous insects in the garden and park. Observations included an eastern tiger swallowtail butterfly, five-banded tiphiid wasp, common oblique syrphid fly, many common eastern bumble bees, and more.


Fish crow at its McGolrick Park nest in April, 2016

Fish crow at its McGolrick Park nest in April, 2016

In addition to adding our own bird sightings to eBird, we encouraged others to record sightings as well. The eBird database now has 40 species recorded in McGolrick Park, encompassing warblers, sparrows, woodpeckers, raptors, and more–all in this four-acre park in Greenpoint, Brooklyn. The full McGolrick Park eBird checklist can be viewed here. During our surveys, we got to observe a nesting pair of fish crows in the park on numerous occasions that have apparently been nesting there for several years. We hope locals were inspired to keep birding in the park and logging what they see on eBird, as well as help maintain the Urban Oasis native plant garden for the birds, bees, and butterflies. The results of the surveys are evidence of the importance of green space in urban environments, and proof that birds are all around us if we take the time to look!

A common oblique syrphid fly on a black-eyed susan in the Urban Oasis

A common oblique syrphid fly on a black-eyed susan in the Urban Oasis


Greenpoint Community Environmental Fund


Funding for all events provided by the Office of the New York State Attorney General and the New York State Department of Environmental Conservation through the Greenpoint Community Environmental Fund.


Tribute in Light Monitoring 2016 Recap

Birds 'trapped' in the Tribute in Light Memorial's Beams

Birds 'trapped' in the Tribute in Light Memorial's Beams

The Tribute in Light memorial once again shone bright over Lower Manhattan on September 11, projecting two beams of light into the night sky to pay tribute to the lives lost on that day in 2001. NYC Audubon has monitored the memorial since 2002 to ensure that night-migrating songbirds, which in some years are attracted in huge numbers to the Tribute’s powerful light beams, are not exhausted and injured during the all-night event.



NYC Audubon staff, board members, and volunteers monitored this year’s memorial from 8pm Sunday night to 6am Monday morning. At around 11pm on Sunday night, migration activity began to increase and many birds were observed ‘trapped’ in the light, circling and calling to one another. Thank you to Michael Ahern Production Services, Inc. and the National September 11 Memorial and Museum for letting us turn the lights off three times for a brief period during the early morning hours, allowing birds to continue on their migration.


Here is a video taken by our monitoring staff of the lights being turned off at one point in the evening because of too much bird activity:



There were many species observed throughout the night, including American redstarts, black-and-white warblers, Baltimore orioles, and cuckoos. We even saw a peregrine falcon that was taking advantage of the congregation of small birds.


A Praying Mantis Joined Us!

A Praying Mantis Joined Us at One Point during Our Long Night of Monitoring!

Birds weren’t the only things we were watching though; we brought along a bat detector that was able to detect six different species of bat flying overhead! We even had a visit from a praying mantis around 3:30am. Be sure to check out NYC Audubon’s Facebook page or our Twitter page for more photos and video from the event.


Also, check out this wonderful video produced by NY Daily News about our Tribute in Light monitoring:


VIDEO: How Birds Are Saved during 9/11 Tribute in Light Memorial, produced by NY Daily News




To learn more about the work NYC Audubon does to protect migrating birds, visit our Project Safe Flight page.


-Conservation Biologist Debra Kriensky


Photo Gallery from This Year’s Tribute in Light Monitoring 

Jamaica Bay Project Awarded Prestigious Five Star and Urban Waters Restoration Grant by NFWF

We are very happy to announce that our proposal for a comprehensive program to protect and enhance the habitat for shorebirds and other wildlife in Jamaica Bay, and to foster a commitment to stewardship by local residents, was awarded a grant under National Fish and Wildlife Foundation’s prestigious Five Star and Urban Waters Restoration Program. Our project was one of 58 community-led wetland, stream, and coastal restoration projects awarded grants this year  through the program.


Our project will protect migratory and nesting shorebirds in Jamaica Bay by engaging hundreds of volunteers; restoring 22 acres of habitat; and organizing beach cleanups at Plumb Beach and North Channel Beach, a marsh-planting event to plant Spartina on Jamaica Bay’s marsh islands, and a dune-planting event in Averne, in the Rockaways.


We will continue our longstanding citizen science program of monitoring shorebirds and horseshoe crabs in the Bay and will also add an educational component: a three-part unit designed to teach Brooklyn middle schoolers about the ecology of Jamaica Bay and the connection between shorebirds and horseshoe crabs. Our project will also continue to increase awareness of and decrease disturbance to nesting birds through “Be a Good Egg” program outreach events.


We will announce details on future volunteer events and citizen science opportunities related to our Jamaica Bay project on our volunteer page and our monthly eNewsletter, The eGret.


We look forward to working on these efforts with our project partners, which include the Rockaway Waterfront Alliance, the American Littoral Society, Sadhana, New York University’s Wallerstein Collaborative, Audubon New York, New York City’s Department of Parks & Recreation, and New Jersey Audubon.


The Five Star and Urban Waters Restoration Program seeks to develop nationwide community stewardship of local natural resources in order to preserve these resources for future generations and enhance habitat for local wildlife. Since 1999, the program has supported more than 820 projects, with more than $9.8 million in federal funds, $7.9 million in private and corporate contributions, and $67 million in matching funds at the local level. Programmatic support for 2016 Five Star and Urban Waters program is provided by the Wildlife Habitat Council, and major funding by the U.S. Environmental Protection Agency (EPA), the U.S. Forest Service, the U.S. Fish and Wildlife Service, FedEx, Southern Company, Bank of America and Alcoa.


We are grateful to National Fish and Wildlife Foundation and their partners for this tremendous support. The Jamaica Bay watershed is a 21,000-acre estuary that supports 325 species of birds and many species of fish, reptiles, and amphibians. Despite its location within the most densely populated city in the U.S., Jamaica Bay is a globally recognized Important Bird Area and is particularly important for shorebirds migrating along the Atlantic Flyway.


Horseshoe Crab Monitoring 2016 Recap and Results

NYC Audubon Conservation Biologist Debra Kriensky breaks down the horseshoe crab numbers from this year’s monitoring efforts in Jamaica Bay


Horseshoe Crabs Photo by NYC Audubon

Photo: NYC Audubuon

We are happy to report that 2016 was a great year for horseshoe crabs in Jamaica Bay!


New York City Audubon once again ventured out during the new and full moons in May and June to count and tag spawning horseshoe crabs. This was our eighth year collecting data on horseshoe crabs in Jamaica Bay, part of a larger project run by the New York State Department of Environmental Conservation and Cornell University Cooperative Extension.


In 2015, a colder than usual spring resulted in unusually low counts at some of our beaches, such as Plumb Beach East. This year, however, the shores were full of mating horseshoe crabs and our counts indicate that numbers continue to stay relatively stable in Jamaica Bay. This is great news, given how important horseshoe crab eggs are to the migratory shorebirds that come through New York City each spring on their way north.


With the help of 163 volunteers (a record!), we were able to count spawning horseshoe crabs at four locations: Plumb Beach East, Plumb Beach West, Big Egg Marsh, and Dead Horse Bay. Spawning activity peaked during the full moon around Memorial Day this year. The high counts were 205 crabs at Plumb Beach East, 21 crabs at Plumb Beach West, and 451 crabs at Big Egg (and that was only what we counted in our quadrat samples!). At Dead Horse Bay, where we take a total count of the horseshoe crabs, the high count was 493.

Volunteers Counting Horseshoe Crabs, Photo by Tracy Pennoyer

Volunteers Counting Horseshoe Crabs, Photo by Tracy Pennoyer

We were able to tag 797 crabs this year, making a total of 4,380 horseshoe crabs tagged since we started in 2009. We had 78 re-sightings of tagged crabs this year – 55 of which were tagged earlier in the spawning season, indicating that many of the horseshoe crabs we see stick around at the same beach for several nights and even weeks.


We also saw nine crabs we had tagged in 2015, two we had tagged in 2014, and one had tagged in 2013! In addition to all of these horseshoe crabs that are returning to the same beach night after night and year after year, we also saw 10 tagged crabs that were put out by other organizations. So far, we know that one was tagged last year in Cliffwood Beach, NJ and another was tagged in 2012 at Breezy Beach in the Rockaways. It will be interesting to eventually find out where and when the others were tagged.


If you ever spot a tagged horseshoe crab, write down the number and report where and when you found it to the U.S. Fish & Wildlife Service here.

Tagged Horseshoe Crab Photo by NYC Audubon

Horseshoe Crab Tagged "341401"

Thank you to all the amazing volunteers who came out to count with us this year, especially our dedicated volunteer site coordinators, who make it all possible! We’re also very thankful to Patagonia, the Williams Companies, and Investors Bank Foundation for their generous support of this year’s horseshoe crab and shorebird work.


We’re already excited for next year’s spawning season! We hope to have another record number of volunteers for next year’s counts. Please email if you are interested in getting involved in this important (and fun!) citizen science study.


New York City’s Common Terns

Common Tern and Chick on Governors Island © Barbara Saunders

Common Tern and Chick on Governors Island © Barbara Saunders

NYC Audubon Director of Conservation and Science Susan Elbin reports on our work with the New York State threatened Common Tern:


The common tern (Sterna hirundo), a native North American waterbird, was nearly extirpated from North America by the millinery trade in the late 19th century, and again by habitat loss and environmental contaminants in the mid-20th century. Thanks to the Migratory Bird Treaty Act and other conservation efforts and environmental regulations, this species has been brought back from the brink of extinction. But populations have not returned to historic levels. The common tern continues to be a threatened species in New York State, and maintaining current population levels requires management to protect the breeding population. The major threats to tern populations on their breeding grounds appear to be space limitation due to habitat destruction and competition with other waterbirds. Common terns are also threatened by specific consequences of climate changes such as warmer summers and severe storms that impact shoreline nesting areas.


Common terns have been nesting in the Jamaica Bay area for decades. Just recently, a colony has established itself on the decommissioned piers of Governors Island. Just a ferry ride from lower Manhattan, the birds can been seen plunge-diving for fish to feed their growing chicks.


While the majority of our conservation and monitoring efforts occurs during the breeding season, common terns spend less than one-third of the year on their breeding grounds. Threats during the other two-thirds of the year, during migration and wintering periods, are unknown. We have initiated two pilot studies using high-technology techniques: geolocators and nanotags. A geolocator is a tag that the bird wears around its leg. The tag can later be removed from the bird in order to download latitude/longitude data collected over the course of one year. Nanotags are small radio transmitters attached to a bird’s back that send a signal to stationary VHF towers installed along the eastern seaboard of the U.S. and across Canada. Results from these two projects will indicate where the birds have spent the winter and how long they stay in a given area, respectively. The goal is to determine what areas New York City common terns are using as stopover sites during migration and over the winter. We plan to expand this project in the coming years, working with partner organizations to increase the sample size and to collect more data about the trends in migratory and overwintering behavior as well as the amount of variation in this behavior within the population. Determining where these birds migrate and overwinter is the necessary first step in identifying threats to the population during these times of the year, when the majority of mortality likely takes place.


Join us for the “It’s Your Tern” festival on Governors Island this Saturday, July 16! Learn more here.



Annual Audubon Christmas Bird Count Results Now Available


Great Horned Owl © Francois Portmann

Great Horned Owl © Francois Portmann

The results from the 116th Annual Audubon Christmas Bird Count are in! The 2015 Lower Hudson count took place on Sunday, December 20th, a cold but clear day. The Lower Hudson count circle (code: NJLH) includes Manhattan and parts of Hudson and Bergen counties in New Jersey.


With the help of 174 participants, we counted a total of 27,167 birds and 96 species this year. Though a little lower than last year’s numbers (30,641 birds and 111 species), there were still a lot of birds counted, showing that winter can be anything but boring!


Counts took place in Central Park, Inwood, Harlem, Riverside Park, Randall’s Island, Bryant Park, Madison Square Park, Stuyvesant Town & Cove, East River Park, Lower Manhattan, and many locations throughout New Jersey (see map below). We thank all of the count leaders who made this year’s count possible, including a count during “count-week” on Governor’s Island.


For detailed results on this year’s count and results from previous year’s counts, please visit our Audubon Christmas Bird Count page

-Debra Kriensky, Conservation Biologist