Some excerpts from CLO's '05-'06
report are below (the bold font is mine).
If you read the report carefully, it's actually quite devastating to the central "body of evidence" argument of the believers. Glimpses, bark scaling/grooves, cavities, and ARU data all seem to get a new, more skeptical treatment now (I hope Hill and Mennill take note):
Remote Time-lapse Video Cameras—During 123 camera deployments we monitored 88 unique cavities and 35 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). Other species detected at cavities included raccoon (Procyon lotor), Northern Flicker (Colaptes auratus), Redheaded Woodpecker (Melanerpes erythrocephalus), Red-bellied Woodpecker (M. carolinus), Carolina Wren (Thryothorus ludovicianus), Eastern Screech-Owl (Megascops asio), and Wood Duck (Aix sponsa). In 11 of 35 (31%) 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. Other species detected at foraging sites included Downy Woodpecker (Picoides pubescens), Hairy Woodpecker (P. villosus), Northern Flicker, White-breasted Nuthatch (Sitta carolinensis), and Brown Creeper (Certhia americana). IBWO was not among the species we documented at either type of target. Despite this, we believe the use of remote time-lapse surveillance cameras is a cost effective tool in the search for the IBWO and perhaps represents our greatest chance for capturing high-quality images of the species.
...
...Based on these observations, our confidence that a double-knock event was produced by an IBWO would be greatest if the event exhibited all of the following characteristics:
• loud, resonant, woody sound
• inter-knock interval in the range expected for ivory-billed woodpecker (55ms–115ms)
• amplitude ratio of second to first strike in the range known for Campephilus (0.4–1.7)
• absence of prolonged low-frequency reverberation
• absence of known duck vocalizations or wing whistles
• absence of other woodpecker drumming or vocalizations
• two or more double knocks in a series within several minutes
...
In BDV, the number of definitive encounters with IBWO decreased from 6 to 1 to 0 during the course of three consecutive search seasons (February 2004 to April 2006) (Table 7). Search efforts were high in the three years, especially in the most recent two years, so the decreasing encounter rates indicate infrequent use by IBWOs or that the individual that was detected during 2004 has left the area.
...
Several people who were not part of our organized search effort reported brief sightings from BDV of woodpeckers with one field mark matching IBWO or possible sounds of the species. These reports must be treated with caution in view of the heightened expectations that many visitors brought into the field after massive media attention in the spring of 2005. All reports were followed up with field searches by members of the organized search, but these yielded no additional sightings or confirmation of the original encounter.
...
We do not believe that disturbance by researchers and day visitors caused the bird to leave the [Bayou de View] area...A more plausible explanation for the presence and then apparent disappearance of IBWO in BDV is that in 2004 and 2005 a dispersing or wandering individual temporarily frequented the area.
...
...no Blue Jay kent-like have been found in the CLO Macaulay Library sound archives.
...
Given the tremendous amount of time and effort expended and the very large number of false or ambiguous detections, the general use of ARUs to continuously record during future search efforts may not be cost effective.
...
Searcher Sean Clawson observed from an oblique angle a foraging PIWO engaged in chiseling and excavating. After the bird left, Clawson walked up to the worked spot and found fresh horizontal grooves. With a ruler the grooves measured 6mm wide at the bottom, i.e. wider than thought possible for PIWO by Sykes et al., although these authors recommend use of calipers for measurements.
...
We envision using two additional tools in exploring new areas in the Big Woods and generating new leads to the whereabouts of IBWO. One is the posting of a $10,000 reward for information and documentation leading to a site predictably used by the species. This approach was initiated in June 2006 by The Nature Conservancy (TNC) Arkansas Chapter and the Arkansas Game and Fish Commission (AGFC). Reports generated by this approach will first be followed up by Allan Mueller of TNC and Catherine Rideout of AGFC, and if reports are valid, dedicated research will follow by CLO and partners. The second approach is a volunteer effort during the 2006–07 season on a scale similar to that employed in the 2005–06 season.
...
Forest management anywhere in the Big Woods should put more emphasis on retention and increased densities of large diameter trees, stressed trees, and dead timber. Details of such measures are currently being discussed within the national IBWO Species Recovery Team. Cavity inventories should be conducted in areas where cutting or other operations are planned. A “morticulture” experiment was initiated by TNC in the summer of 2005, involving the attempted killing and stressing of several trees in four-acre plots. A timely effort recommended here is to repeat this experiment on NWR land at a larger scale of one or more 40- to 70-acre plots and with a higher proportion of targeted trees in the plots. Ideally, this could be done in combination with efforts to create new canebrake areas for other species of concern.
...
Currently we are working with Dr. Michael Scott of the University of Idaho and other colleagues on a modeling study that examines what number of IBWOs might be present in the searched area of the Big Woods given the parameters of our search effort and encounter rate.
...
We will continue to develop and refine our technologies to enhance future search efforts, and we are eager to share our expertise in any form that benefits the search or conservation efforts for IBWO throughout its range.
Posts
