An Anthropogenic Double Knock and an Apparent Double Knock in Apparent Response

I recorded this today in the northern sector.

The first sound is Frank Wiley’s double knock with cypress dowels on a tree. The response comes approximately nine seconds later. There was no human activity in the vicinity at the time, and the spectrogram makes it clear that the source is natural. The intra-knock interval appears close to what would be expected for a large Campephilus woodpecker, approximately .11 seconds.


This was at a site where we’ve now got two cameras deployed. Frank will be posting a discussion of the pros and cons of game cams in the near future.

Edited to provide more context: I should have included this potentially significant detail – prior to my turning on the camera, Frank Wiley heard an ambient single knock that I missed. This was followed by agitated calling from a Pileated Woodpecker, Barred Owl vocalizations, and scolding from several Red-headed Woodpeckers, all of which I heard. The single knock gave him the impetus to do a single ADK. Thus, the circumstances were somewhat different from the typical use of ADKs as an attempt to attract or generate a response.

On further edit 12/31: I’ve modified the title from “. . .Apparent Double Knock in Response” to “Apparent Double Knock in Apparent Response” to correct the logical fallacy in the previous headline.

6 thoughts on “An Anthropogenic Double Knock and an Apparent Double Knock in Apparent Response

  1. Hi Mike. Exciting post there. I am hoping you get this while still in the field. There is some evidence, logic and forum conversation for the DK being a sound that IBWOs will respond to, but keep a distance from ( even though you have written about doubting this). Perhaps, on your last field day there (and especially if you have an IBWO nearby!), you might try the nesting sounds that were recorded long ago by Kellogg. Cornell tried a nest call and the bird returned the call for 18 minutes. I believe that this call combined with great camo, or a blind, might bring the bird in. Good luck in any case. John Williams,

  2. Thanks John. I’m not aware of the response to playback you’re describing. If you have a reference, it would be great if you could post or send it. This whole process is kind of archeological. We’re trying to piece things together based on fragments. Not sure playback will be feasible this trip.

  3. There are some issues with using playback. Jackson’s account suggests it may have attracted birds to a distance of 100 yards but no closer. It didn’t lead to a sighting (or a recording of the reported vocalizations.) It bears remembering that the John’s Bayou birds, while habituated to human presence, were likely quite agitated by the large, metallic, human operated object just under their nest. That said, there may be a place for the very judicious use of playback.

    Regarding IBWOs returning to the same place year after year, I think it’s a both-and situation that depends on food supply. The John’s Bayou birds had strong site fidelity for over a decade, but I also find the “disaster species” model to be quite compelling.

  4. One more comment to summarize, since I sometimes write a bit obtusely–
    1. I believe that DKs have never brought a bird very close.
    2. The vocalizations Jackson reported caused the bird to respond for 18 minutes. I think this is a key point, showing the bird wanted to get closer. I believe it saw what was happening, and was stopped by negative visual cues– thus my remark on camo, or a blind. I believe it is more likely that nesting sounds cause a gregarious behavior in birds, and the double knock is territorial.
    3. The birds are certainly nomadic. That’s why there may be a year when they leave your search area (hopefully not). This happened to Mike Collins and Geoff Hill. So I wish you the best of luck as soon as possible!


  5. Thank you! We think we’ve had at least one instance in which an ADK brought in a bird. They work as an attraction method for congeners, so I don’t think they should be ruled out, but neither should playback.

    The question of nomadism is complex. Geoff Hill has said publicly that he suspects the birds were driven out due to the intrusiveness of the search efforts in the second year. It’s not entirely clear that the birds are gone from the Pearl. The literature on this is ambiguous, and it’s beyond dispute that the John’s Bayou birds had site fidelity. I suspect that they’ll stick around if there’s food and not too much disturbance.

    Happy New Year!

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