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Cornell's final summary report of their 2005-6 search season in AR. is finally available (pdf) here:
http://www.birds.cornell.edu/ivory/current0607/FinalReportIVBWOO.pdf
Haven't finished reading it yet... may or may not have more to say about it in days ahead. For now I'll just say, better late than never...
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1 comment:
I'll just quote some interesting snippets without comment:
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[Remote camera observations]
Remote time-lapse Video Cameras—During 12 camera deployments we monitored 88 unique cavities and 5 feeding trees. In 51 of 88 (58%) deployments at cavities, we captured images of nine different species, with squirrels (Sciurus spp.) and PIWO being the most common (Photo 9).
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In 51 of 88 (58%) deployments on bark-scaled trees, we captured images of six different foraging species, with PIWO the most common and the only species detected scaling bark.
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IBWO was not among the species we documented at either type of target.
[Sightings]
Visual—There were 14 possible visual encounters with IBWOs during the 2005–06 field season. Ten of the 14 encounters were glimpses of birds that witnesses said gave them an impression of something different than the superficially similar PIWO but yielded no discernible field marks. ...Of the remaining four encounters, one was reported by a volunteer searcher and three by members of the public. In each case, the observer noted and described a single field mark: a broad band of white on the trailing edges of a flying bird (two observations) or a large white patch in the lower part of the folded wings of a perched bird. Encounters of this type (when one field mark is clearly observed) are suggestive of IBWO but cannot be considered definitive. ... No definitive or confirmed visual encounters took place during the 2005–06 field season.
[Acoustic monitoring]
In January 2005 an ARU in the WRNWR recorded kent-like calls that were suggestive of IBWO vocalizations. For a more detailed analysis of these sounds, see Charif et al. 2005. However, it is also possible that these calls were produced by a Blue Jay.
[Discussion of double-knocks]
As noted in the results section, we believe that duck wings produce double-knock sounds with surprising frequency. In the field, we have observed Gadwalls and Mallards producing double knocks both in flight and during a short wing whir given while on the water, directly after preening. ...Yet some apparent duck-generated double knocks are surprisingly crisp and may be mistaken for woodpecker knocks, especially at a distance. Some of the sounds of unknown origin presented by Charif et al. (2005) may be duck knocks.
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