top of page

A Brief History of the Night Migration of Birds in NYC 1887 - 2021

Updated: Sep 26, 2021

Black-and-white Warbler (adult female) in Central Park on 18 September 2021 by Deborah Allen

23 September 2021

Bird Notes: Due to the forecast of rain including thunderstorms for Friday morning, we have CANCELLED tomorrow's (Friday 24 September) Bird Walk. See everyone Sat/Sun/Mon: weather looks great then. You can always find our bird walk schedule here on our web site: SCHEDULE

Night migration has a long history of study in NYC: the first ornithologists at the American Museum were trying to determine if and when birds migrated at night. J.A. Allen, F. Chapman and others became interested in Lighthouses along the east coast of North America where many birds were found dead in spring and fall because of the attraction to bright light in otherwise total darkness as birds presumably migrated at night. This helped scientists determine the timing and magnitude of bird migration including what species were common (and which ones rare). Fast forward to 2021: you might have heard about the several hundred birds picked up dazed/injured/dead in lower Manhattan on Tuesday, 14 September, on the same morning that a "fall-out" occurred in Central Park of night migrating birds. All were forced lower into the atmosphere as they rode a cold front south (with associated winds from the northwest). As this weather system encountered a warm air mass from the south in our area...the resulting fog, clouds and occasional rain dropped the birds low enough to hit buildings, and be confused by some lighting arrays on tall buildings - or land in number in Central Park. This phenomenon happens every few years in NYC, and gets lots of attention because of the number of birds found dead in one area. However, in the long run, collisions with glass at or near ground level kill many more birds in NYC than lights - but not as many at a single event (night). This is a complex subject that many scientists are trying to unravel...and yes light is absolutely a hazard to migrating birds especially on certain nights (weather related) and/or in areas that are otherwise completely dark. We recommend reading the three historical notes below as an introduction to the subject...A book could be written on the importance of NYC in this area of study: migration/birds/night/collisions. HOWEVER all is not gloom and doom: it is amazing to watch small birds migrating at night, as we did in spring/autumn 2004-05 at the open air Observation Deck of the Empire State Building - and the discoveries we made that were new to science. Amazing stuff can be learned/discovered in urban areas...

In this week's Historical Notes, we send three short descriptions of the nocturnal migration of birds in NYC: (a) an 1887 article on dead birds found beneath the newly opened Statue of Liberty on Bedlow Island. Electric lights had been turned in November 1886 - too late in the season to disorient migrating birds - but in mid-May 1887, the first dead birds were found there; (b) a late September 1953 New York Times article on dead birds found at the Empire State Building [ESB]; and (c) an August 2005 summary of night migration at the Empire State Building describing what Deborah and my research project had seen/discovered including information new to science at the time including: night migrating Ospreys; the great extent that Peregrine Falcons hunt night migrating birds; the number of Great Egrets and other herons that migrate at night - and more. HOWEVER, since we did not conclude that birds were colliding with the Empire State Building at the level of the Observation Deck where we were stationed, we became evil birders/bad birders to some in NYC, especially NYC Audubon (whose executive director called the ESB to get our research project stopped), and the Linen Society. Oh Well. We only describe/write about what we see/discover: nothing more, nothing less.

Right now we still remain a little too dangerous for those nice organizations. We intend to stay dangerous - and independent.

Cuckoo Leaf-cutting Bee The Bronx (our yard) on 18 September 2021 Deborah Allen

Yellow-billed Cuckoo Central Park on 18 September 2021 Deborah Allen

Bird Walks for Late September - Early October

All Walks @ $10/person

1. Friday, 24 September 8:30am. Bird Walk. [CANCELLED: RAIN is FORECAST] Conservatory Garden (105th street and 5th Ave) $10. N.B. this walk meets uptown - at the north end of the park...but easy to reach.

2. Saturday, 25 Sept. 7:30am and again at 9:30am. Bird Walk. Boathouse Cafe; 74th street/East Drive $10. If you do the 7:30am walk, you get the 9:30am walk for free.

3. Sunday, 26 Sept. at 7:30am and again at 9:30am. Bird Walk. Boathouse Cafe; 74th street/East Drive $10. If you do the 7:30am walk, you get the 9:30am walk for free.

4. Monday, 27 Sept. 8:30am. Bird Walk. Strawberry Fields (72nd street and Central Park West) $10. N.B. this walk meets at the IMAGINE mosaic inside the park at 72nd - inside the park (about 50 yards from CP West).



1. Friday, 1 October 8:30am. Bird Walk. Conservatory Garden (105th street and 5th Ave) $10. N.B. this walk meets uptown - at the north end of the park...but easy to reach.

2. Saturday, 2 October 7:30am and again at 9:30am. Bird Walk. Boathouse Cafe; 74th street/East Drive $10. If you do the 7:30am walk, you get the 9:30am walk for free.

3. Sunday, 3 October at 7:30am and again at 9:30am. Bird Walk. Boathouse Cafe; 74th street/East Drive $10. If you do the 7:30am walk, you get the 9:30am walk for free.

4. Monday, 4 October. 8:30am. Bird Walk. Strawberry Fields (72nd street and Central Park West) $10. N.B. this walk meets at the IMAGINE mosaic inside the park at 72nd - inside the park (about 50 yards from CP West).


Call (718-828-8262) or Email us with questions:


The fine print: Our walks on weekends meet at 7:30/9:30am at the Boathouse Restaurant (approx. 74th street and the East Drive). Please note: the Boathouse is not one of the buildings that surround the nearby Model Boat Pond - people make this mistake all the time! Fridays we meet at Conservatory Garden; Mondays at Strawberry Fields - check the "Meeting Points" page of this web site for exact meeting location.

Our home phone is 718-828-8262...and Deborah's cell is: 347-703-5554. Email is ( If you are lost and trying to get to the bird walk, call Deborah's cell phone...but remember on weekends there will be 2-3 other people calling who are also lost - please be patient. If in doubt about whether a walk will take place or not the morning of the walk: check the main landing page of this web site as well as the "Schedule" page - if the walk is cancelled, information will be posted there by 6am the day of the walk, and usually by 11pm the night before. If still confused and as a last resort, call us at home - if no one answers it means we left for the bird walk. We end all our Central Park walks (except Fridays) near the Boathouse at about noon; you can get a cup of coffee and a muffin there (around $6 total). Walks last about 3 hrs (less if hot or rainy), and you can leave at anytime - we won't be offended. If you need directions/help to your next destination, just ask someone on the walk - we aim to please.

Red-breasted Nuthatch Central Park 19 September 2021 Deborah Allen

Below: Leafcutter Bee in our backyard (the Bronx) 25 August 2021 Deborah Allen

Here is what we saw last week (brief highlights): Yikes I just realized in retrospect that I originally sent out this bird walk announcement without including a bit of info on what we saw last week...besides links to Deborah's wonderful lists, some verbage is needed to put things in context. Anyway, Friday's walk (the 17th of September) featured a close Cape May Warbler (thanks Paul Curtis) plus eight other warbler species. On Saturday the birding got even better: 13 warbler species; three Red-breasted Nuthatches (first of season); plus Yellow-throated Vireo and a Yellow-billed Cuckoo. By Sunday, more had arrived: 16 warbler species; Scarlet Tanager and a flyover adult Bald Eagle. However, on Monday, numbers had declined. For example, when I played the tape for Swainson's Thrush, I could only summon a handful when during the prior week, getting 20-30 was easy. A total of nine warbler species this Monday 20 Sept - thank goodness for the tape, these warblers were coming in close...And by Tuesday, on a private walk, we had the first Yellow-bellied Sapsucker of the season - I imagine Emmett Logan is smiling as he reads this. An honest man!

Deborah's List of Birds for Friday 17 September: Click Here

Deborah's List of Birds for Saturday 18 September: Click Here

Deborah's List of Birds for Sunday 19 September: Click Here

Deborah's List of Birds for Monday 20 September: Click Here

Downy Woodpecker in Central Park 18 September 2021 Deborah Allen

Below: White-M Hairstreak in our backyard (the Bronx) 21 September 2021 Deborah Allen

Below: Rough-legged Hawk in South Dakota; 20 February 2020 Deborah Allen


Feathered Travelers Killed by Striking the Statue of Liberty

Birds and their Habits Discussed by the Ornithologist Union.

14 November 1889

The congress of the American Ornithologists' Union resumed its session in the rooms of the American Museum of Natural History yesterday forenoon. The attendance was larger than the previous day and included several ladies.

Jonathan Dwight, Jr., read an interesting paper on "Birds that have Struck the Statue of Liberty, Bedlow's Island, New York Harbor." He said that on account of its lighter color more birds strike the pedestal to the statue than the statue itself. The Statue was erected too late in 1886 for the migratory birds, and none struck it that year. The first to strike it was May 19, 1887, and the next late in August, when the lights were said to be put out by birds. Mr. Dwight read a highly-colored newspaper account [see photo below] of the killing of nearly 1,500 birds on the night of August 22-23 [1887]. Its statements excited much merriment. It was utterly untrue that birds were burned or roasted, except in the case of one or two birds which had fallen near the heat. The slaughter of the birds on this occasion was due to the first cold wave of the year, which started the migration. Mr. Dwight also read newspaper accounts of the slaughter of 1888, one account stating that in a single night, 500 birds were killed.

The first date which birds struck the Statue in 1889 was Aug. 5. when 14 were killed. A few others were killed during the month, and a considerable number in September and October. Oct. 24. was the last date at which birds were killed. The whole number killed this year was 690, which was considerably less than in 1888 or 1887. Mr. Dwight began visiting Bedlow's Island Sept. 19 this year and had studied the birds and recorded the species. He found that every cold wave in early fall was followed by migratory birds flying against the Statue. Of the dead birds picked up this year, 60% belonged to one species, the Maryland [Common] yellow throats. The remaining 40% included a great variety.

Discussion followed as to the effect of darkness in causing the destruction of birds and as to whether sparrows and hummingbirds were ever among the migrants killed.

The scientist that is quoted in this New York Times article, Jonathan Dwight, Jr. grew up on 34th street in Manhattan - in the area where the Empire State Building is today. He trained to be a medical doctor but when ornithology became a real profession at the American Museum, he was hired there at about the same time as Frank Chapman (probably by JA Allen, chairman of the vertebrate department at the time - he interested in birds colliding with lighthouses in North America). Dwight did much work on systematics of birds: he is famous for a treatise on gull plumage among other things, and became interested in the Bedlow Island area (now known as Liberty Island) when the keeper of the island began sending boxes of dead birds to the newly formed museum for their collection. Wondering why so many dead birds were coming from the island, a scientist was sent over to have a look. (Remember at this time, many were struggling with the idea of migration - how many birds migrated? when - day or night - did most migrate? when - time of year - did they migrate? how high did they migrate?). So migration was a buzzword, particularly night migration...and when the scientists looked at the map and found Bedlow's Island - they knew it was important because there was no habitat out there to support so many different types of birds - hence they must be migrating (and migrating at night) - and landing on the island.

A few things catch my mind about this article: (a) the number of birds killed at a time when lots and lots more birds roamed the earth than now [= not a lot compared to some cities such as Toronto today/2021]; (b) the association of bird deaths with weather patterns (cold front/wave); (c) many more birds killed in autumn than spring; (d) the variation in number killed one year vs. the next - exactly what they find today in lower Manhattan in the area of the Freedom Tower. Finally, the article above mentions that the birds struck the Pedestal of the Statue, my guess is that there were upward pointed spotlights to illuminate the statue on the pedestal, as well as lights in the torch.

Leslies Illustrated Newspaper (cover illustration) 15 October 1887

Birds Wing to Death Against Empire State

Ira Henry Freeman in the New York Times on 22 September 1953

Large flocks of migratory birds blundered into the Empire State Building on their way south during the dark hours yesterday morning [22 September 1953], and several hundred dashed themselves to death.

Agents of the National Audubon Society identified nineteen varieties among 277 dead birds. They were mostly different kinds of warblers. Six birds were captured alive. They were banded and released by the society last night.

The cause of the mass death remained obscure. The last time a similar thing happened was on the night of Sept. 11, 1948, when more than 300 migratory birds were killed by flying into the Empire State Building, and hundreds more broke their necks against the City Hall tower in Philadelphia.

"We know there was a big flight southward last night," said Kenneth Morrison, public information director of the Audubon Society. "Yesterday, the woods in Westchester, New Jersey and Long Island were almost deserted by birds, but this morning the brush was full of them.”

At intervals in the last few weeks, migratory birds have been flocking down the Atlantic Flyway, from Canada and New England toward the southern states, and some have gone across the Gulf of Mexico to Central and South America, Mr. Morrison explained.

Cold Air Mass a Factor

''A cold air mass moved down upon us from the northwest last evening, he explained, "and the birds must have taken off in large numbers at sundown. Probably they were moved by the colder temperature and by the favorable, southbound wind."

Exactly why some birds were flying so low as to strike the Empire State Building, which reaches 1,250 feet into the air, ornithologists could not deduce. Warblers and kindred species would normally fly nearly 2,000 feet above the earth.

The Empire State Building went dark at midnight, when the charwomen [cleaning ladies] went home. No employees heard or saw birds striking the windows up to then. But about 7 A.M., when porters arrived to begin their day's work, they found scores of small dead birds on the main observation platform at the eighty-sixth floor, a terrace on the eighty-seventh floor and on roof setbacks at the thirtieth and twenty-first floors. Many others were found alongside the building on Thirty-third Street.

The dead birds were piled into two cartons and given to Andrew Bihun Jr. and Miss Rea King, employees of the Audubon Society.

Bay-breasted warblers were the chief victims, with 104 found dead. The birds caught alive were found stunned but unhurt on the setbacks and were taken in cardboard boxes to the Audubon Society headquarters at 1130 Fifth Avenue where Mr. Bihun banded them for identification by students of bird migration. Last evening he released them from his home in Garfield, N.J. The group comprised four yellowthroat and one bay-breasted warbler and one rose-breasted grosbeak.

A warbler is a common bird, smaller than a sparrow, usually with a brown or slate-colored back and a light breast, the varieties having distinguishing marks and colors on the tail, breast, throat and cheeks.

In the 1948 death-flight the birds also were riding a tailwind created by a cold front moving down over New York from the north, Mr. Morrison said. But that air mass was "shallow" and forced the birds to fly low, he explained, whereas the cold front Monday night extended 8,000 feet above the earth.

DEATH ON THE WING: Harry A. Ebert, acting manager of the Empire State Building observation tower inspects some of the 277 migratory birds that were dashed to death yesterday, 22 September 1953.

Date: Tue, 17 August 2004

From:"Robert DeCandido, PhD"

Subject: Night Migration/NYC [NYSBIRDS-L: 12899]


Last night [16 August 2004] at the Empire State Building (ESB) here in midtown Manhattan, there was an extraordinary experience/abundance of birds. At times, I had difficulty hearing someone speak to me since so many birds were making flight calls. I really need a session with Bill Evans in order to distinguish one species from another at night. But if anyone did want to study night flight calls, this would be the place....Anyway, between 10:30pm and 11:45pm, I estimate that there were at least 400 birds circling the tower of the ESB. Most seemed to be warblers (at the ESB, birds at night are difficult to identify to species since the building lights wash out the colors; a few others such as Orioles/Tanagers can be identified). None of the birds collided with the building, and no birds ever came within 15 feet (@5 meters) of the ESB. Also, an adult male Peregrine Falcon flew in at about 11:40pm and made a couple of unsuccessful hunting attempts at individuals in the whirling vortex of birds above my head. This past Saturday evening, a male Peregrine easily caught two birds (one an oriole; the other a warbler-sized bird) in his 8-10 hunting attempts. Peregrine Falcons also were observed making hunting attempts in the spring of 2002 and this past spring (2004) as well. These observations of Peregrines regularly hunting at night are the first such observations for this species. (Other falcons such as the Lesser Kestrel have been observed hunting at night in Spain; Bat Falcons in Asia regularly hunt at dusk/dark; and raptors species such as Marsh Hawks, Peregrines and Levant Sparrowhawks have been observed/tracked migrating at night).

One Nighthawk was chasing and catching moths made easy to see via the lights of the building.

I went up to the ESB Observation Deck last night since the weather forecast was for fog, and I wanted to see its effects upon migrating birds. The good news is that even for the brief stretches when fog partially obscured the tower of the ESB, no collisions occurred, etc. (Late Saturday night it was reported to me that approx. 500 birds landed on the railing, deck and other perching spots when it began to rain heavily.) Better news is that the ESB security guards and on-site personnel (Engineer in charge of lighting) are aware of the migrants. Building Lights were turned off at 12 midnight.

Deborah Allen and myself with the help of many volunteers (Scott Wiley, Rikuro Okamoto, Sandra Critelli, Patricia Essler, Audry Weintraub, Carl Howard, Alice Barner, Mark Kolakowski and others) have been working with ESB Security Personnel to show them the migrants this past spring (2004) and now this autumn. We believe that watching the migrant birds, moths, bats etc. improves their work experience, and gives them something to enjoy. They really like the birds, and watching them flying in the dark is a wonderful, fun experience....Building Management has been incredibly responsive, nice, and receptive to our research efforts. They have been a model for how scientists and the private sector can work together to achieve shared goals. We have the highest praise and respect for ESB personnel and their efforts on behalf of doing what they can to insure a safe flight.

Deborah and I will have more to say about night migration from the ESB in the coming weeks. In NYC, the study of night migration has a long history (to at least 1887), and we want to bring that to light.


Deborah Allen and Robert DeCandido PhD

Follow our Bird Sightings on Twitter: @DAllenNYC and/or @BirdingBobNYC

Reservoir, Central Park looking southeast from the northwest corner

23 September. ALL DONE with the windows - all installed. The Bay Window above is in the rear of the downstairs living area - and is the smallest of the Bay Windows at about 72 inches wide and 55 inches high. Now for cleanup and putting things back in place. So much fine dust...and so much stuff we really don't need = a good time to downsize.


Robert DeCandido PhD
Robert DeCandido PhD




Well done, Bob and Deborah! The definitive seminar on night migrations and their pitfalls

The path from King Jagiello has become popular with several groups, as they come by as early as 8:30 in parties of six or twelve. Leaders vary.

Today I witnessed a large water fowl enter from the West and hide in a tree before me. It

lingered for almost an hour and I believe flew into Turtle Pond, where, perhaps, folks will find it in the next day or so. It was black and white. Egret? Heron?


Great newsletter once again! Love the window!

bottom of page