Tales Told by Whooping Crane Voices
    Dr. Bernhard Wessling's Winter 2000/2001 Results

    Dr. Wessling with wind-proof microphone.
    Photo Brian Johns

    Dr. Bernhard Wessling is a crane vocalism expert from Germany. He traveled to Aransas National Wildlife Refuge in the winter of 2000/2001 to continue his work in recording crane voices. After returning to Germany, he started analyzing the many recordings he made —about 150 files.

    "I keep track of comments where I am, from where I recorded," Dr. Wessling said, " and the location where the calls came from. The files comprise calls from 25 to 27 crane pairs. I will try to match these with the calls recorded in the winter of 1999-2000. Then we will see:
    • how many pairs are still in the same territory.
    • how many pairs may have changed territory and / or mate."

    Crane Recording Results from Winter 2000/2001
    In March, Dr. Wessling wrote to Journey North to share the exciting results of analysis. Here is his summary of the analysis of all calls recorded in winter 2001, and their comparison with the calls and analyses from winter 99/00:

    For winter 1999/2000, I found an additional pair in the previous call data due to the comparison with the new calls. Hence, winter 99/00 gave 28 pairs, and not 27. The new pair is "#16A," so named because it is between territory 16 and 17 (and may have been overlooked from the air).

    Winter 2000/01, we recorded 31 (!) different pairs. Twenty-three gave their unison call (UC), 19 the guard call (GC), and 11 gave both UC and GC.

  • 21 pairs have been found back again and identified with those from winter 99/00.
  • 10 pairs are new (or, if you count the "16A" from 99 as new, then 11).
  • 7 pairs have not been found again. I assume also considering Tom's information, that 5 of them are dead (at least one partner). Two 2 may be present, but did not call in my presence.
  • 4 pairs (= 20%) have significantly shifted their territory, one pair even by 7 units (from territory #13 to #6A).
  • 2 pairs (10%) have a new mate. One male took a new female (#15), and another female took a new male (#36).

    Altogether, we now have 40 pairs in the wintering grounds; probably only 36 of them are still living. Seven of nine pairs recorded by Brian in summer have been matched with calls they made in winter.

    This means that we know about 80% of all adult pairs, and we begin to learn more about their life and changes in their life (such as changes of territory or changes of mates). Here's one good example:

    Mr. Lobstick, Did You Lose Your Band?
    For one pair (called "Lobstick", #17), I was able to confirm that the male had lost his band. Brian had observed that the male was wearing its band in spring. Then the pair had a chick, and the male was without his band. Brian concluded that the male had lost the band, but we could not be sure. Luckily, I had their acoustic signature and was able to prove that the male is indeed the same one. This is very good luck because the male is one of the oldest known, going back to the time when people were still banding. It is 22 years old. Without his band for positive identification, we would not have had the chance to exactly know when this 22-year-old male eventually dies. But now the positive identification from his voiceprint will enable us to follow him over the next years, too, until the end of his life.

    Read about Dr. Wessling's work with crane voiceprints here: