Some video from last night/ this morning

Here are some video clips that I took tonight, of birds flying across the moon during migration. The birds are small, and they move quick, so it’s best if you click on the movie to open YouTube in a separate window (and therefore bigger).

And here’s a photo of my setup:
Watching nocturnal migration

Okay- I’m off to sleep now!

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5 responses to “Some video from last night/ this morning”

  1. Thanks to Bob DeCandido for sending this great email:

    Dear David et alia,

    You are following in the footsteps of some fairly well-known folks:

    Citation: Chapman, F.M. 1888. Observations on the nocturnal migration of birds. Auk Vol. 5 (1): 37-39. (Jan.-March 1888)

    MR. W. E. D. SCOTT’S papers on this subject (Bulletin Nuttall Ornithological Club. Vol. VI, pp. 97, 188) have not to my knowledge been followed by any of a similar character, and, the facts to be determined being of such vital interest, I feel urged to present the results of my own observations, limited though they be, as a slight contribution to the larger amount of data we must amass before arriving at any strictly accurate conclusions concerning every phase of the nocturnal journey of migrating birds.

    The following notes were obtained with the assistance of my astronomical friend, Mr. John Tatlock, Jr., on the night of September 3, 1887, at Tenafly, New Jersey, about three miles west of the Hudson River, Mr. John F. Paulison most courteously having placed his observatory and 6-inch equatorial telescope at our disposal. The most important facts to be determined in observations of this nature are, of course, the height at which these flights occur, and also the number of birds which cross the field of view at any given time.

    The method adopted was the same as that used by Mr. Scott, the telescope being pointed at the full moon, which served as a background, showing with wonderful distinctness the birds as they crossed, the observer calling to the recorder as each bird came into view, the latter noting the time. These observations appear in the following table, where also are given the apparent altitudes of the moon computed at ten minute intervals during the period of observation.

    From the altitudes are computed the heights at which the birds in the field at that time were probably flying. The problem of determining this height exactly is not, so far as we can now judge, capable of definitive solution, for the reason that we have no means of ascertaining the distance of the bird from the observer. In this case, therefore, we are compelled to resort to an hypothesis of the probable distance at which a bird was visible, and we thus assumed that the least distance from the observer at which a bird could be seen was one mile, the greatest five miles, feeling sure that, in accepting these limits, we do not over-estimate the greater distance.

    In this connection the appearance of the birds as they crossed the field is of great importance, those which passed more slowly being obviously the ones at the greater distance; and in this class are included the few possessing some marked characteristic of flight which rendered identification possible; these were as follows: at 8:34pm a Grackle, at 9:22pm a Carolina Rail, at 9:26pm two Carolina Rails, at 9:30pm a large Snipe, at 9:33 a Carolina Rail, at 10:15pm Carolina Rail, and at 10:44 a Duck.

    The major portion, however, passed at what may be termed the middle distance, or, in other words, too rapidly for us to more than distinguish that they were birds. During the first half hour of observation a number of birds were seen flying upward, crossing the moon, therefore, diagonally, these evidently being birds which had arisen in our immediate neighborhood, and were seeking the proper elevation at which to continue their flight, but after that time the line of flight was parallel to the earth’s surface, the general direction being south.

    In the appended table the figures given in the vertical columns headed 1, 2, 3, etc., are the numbers of birds observed per minute, the time being found by adding to that of the left-hand column the desired number at the head of the column following; to the right appear the totals and altitudes.

    In conclusion I desire to express my thanks to Mr. Paulison for so courteously permitting us to use his observatory, and especially to my friend Mr. Tatlock, who, in preparing its astronomical portion, deserves entire credit for whatever value this paper may possess.
    Formatting on this listserv does not allow the presentation of the Table that accompanies this note by Frank Chapman. However, it can be found via:

    just type in Frank Chapman in the author search area, and the date of publication (1888).

    In three hours time that September night in 1887, Chapman counted 262 birds passing along the face of the full moon – quite a small area of study. Are there fewer migrants in 2007? Probably – but hey David, what do you think? Roughly how many did you count passing across the moon?



  2. Bob et al.

    I’ve often wanted to do this in a systematic fashion, but I never seem to have the time, right conditions, etc. Sid Gauthreaux has done this extensively, and continues to develop computer programs to make the process more quantifiable. In fact, he used moon watching as a means to quantify the radar echoes when the new NEXRAD system went up in 1988. A search for “moon watching” and “Gauthreaux” on SORA should yield some nice reads. I know David Mizrahi (also NJ Audubon, and a Ph.D. student of Sid’s) did some of this moon watching as a graduate student when working for Sid at Clemson University. Bob Fogg, at NJ Audubon has also worked out some of the calculations, although we’ve only discussed them in passing.

    Thanks so much for sending this info!



  3. Back in the early ’90’s I was a volunteer at Canaveral National Seashore and working on the Florida Breeding Bird Atlas. I met a guy who was staying in one of the in holder houses. His name is Bill Evans and he was doing migration studies under a grant from Cornell. He set up microphones in a triangulated pattern at the Seashore and at the New Smyrna Beach Airport. Then he used video tape to collect the sounds of the flight calls of migrating birds passing overhead. When he began the project, he’d spend the morning playing snippets of the tape and write down what he was hearing and the numbers. Later on he worked out a computer program that was interfaced with a program that was designed by an audio engineer at Cornell that utilized a recognition protocol to allow the computer to identify the birds by their calls as shown in sonogram form. Finally, using a formula developed by a math student that was able to interpret the information from the triangulated microphones, he could access information relative to direction of travel, altitude, air speed and direction. He could input all of this into the computer and get a print out that told the species, their numbers, their altitude, direction of flight and speed. His idea was to have listening posts set up along all of the major flyways that people could log into via the Internet (which at that time was still kind of a new concept) to find out what was migrating through their area at the time.
    I have no idea what ever happened to this wonderful idea. I only met Bill that one time when he showed me what was then a rather rudimentary set up. I don’t know if there was a problem with financing or proprietary technology or what. But having worked on the NAMC counts since then, I can say that that morning I saw the future of migration bird counts.

    David Hartgrove
    Daytona Beach, FL


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