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Bioacoustics CJZ articles

Subject: Bioacoustics CJZ articles
From: adam frankel <>
Date: Fri, 30 Apr 2004 11:33:20 -0700
Tests of two functions of alarm calls given by yellow warblers during nest
 Sharon A. Gill and Spencer G. Sealy 
 Can. J. Zool./Rev. Can. Zool. 81(10): 1685-1690 (2003) 
 During nest defence, yellow warblers (Dendroica petechia) give "seet" and
 "chip" calls. Seet calls are given preferentially toward brood parasitic
 brown-headed cowbirds (Molothrus ater) during the yellow warblers'
 egg-laying period, whereas chip calls are given toward mammalian and avian
 nest predators throughout the nesting period. In this study, we investigated
 two possible functions of seet and chip calls during nest defence by playing
 alarm calls to nesting yellow warblers. We tested whether nest owners give
 seet and chip calls during defence to alert their offspring and their mates
 about nest threats and, in the latter case, whether the alarm calls differ
 in function depending on nesting stage. In response to playbacks, nestlings
 remained inactive for a significantly longer period when chip calls were
 played than when seet calls were played. Female yellow warblers returned to
 their nesting areas more quickly when seet calls were played than when chip
 calls were played, but pairs were equally likely to return to the nesting
 area in response to both call types. These findings suggests that both seet
 and chip calls alert mates but that only chip calls function to alert
 nestlings of potential danger. 

>From  Fri, 30 Apr 2004 11:35:38 -0700
From: adam frankel <>
Date: Fri, 30 Apr 2004 11:35:38 -0700
Subject: Bioacoustics articles, Can. J. Zool.

decline and applications for breeding bird surveys
 Silke Nebel, Brian J McCaffery. Canadian Journal of Zoology. Ottawa:  Oct
 2003. Vol. 81, Iss. 10;  pg. 1702 
 We documented vocalization activity of breeding shorebirds at two sites in
 northern and western Alaska, on the Colville River Delta and on the Yukon -
 Kuskokwim Delta. At both sites, number of calling individuals decreased
 throughout the season. Variation in vocalization activity was significantly
 higher at the Colville River Delta towards the end of the season, while
 weather variables affected vocalization activity only on the Yukon -
 Kuskokwim Delta. Our results highlight the importance of timing, weather,
 and site-specific attributes on number of birds detected. We discuss our
 findings in the context of different methods to monitor breeding shorebirds.
 Effect of underwater seismic surveys on molting male Long-tailed Ducks in
 the Beaufort Sea, Alaska 
 Deborah L Lacroix, Richard B Lanctot, John A Reed, Trent L McDonald.
 Canadian Journal of Zoology. Ottawa:  Nov 2003. Vol. 81, Iss. 11;  pg. 1862,
 14 pgs 
 Large numbers of Long-tailed Ducks (Clangula hyemalis) (10 000 - 30 000)
 undergo a postnuptial wing molt along barrier islands of the Beaufort Sea,
 Alaska. To investigate the potential effects of underwater seismic
 activities on this species, we monitored the number and diving behavior of
 molting Long-tailed Ducks before, during, and after seismic activities in a
 seismic area and two 
 control areas nearby between uly and September 2001. Aerial surveys
 documented a decline in duck numbers in both seismic and control areas
 during the period of seismic activity. We used automated data-collection
 computers to monitor the presence and diving behavior of radio-equipped
 Long-tailed Ducks residing within 2.5 km of a series of computer setups
 located along the barrier islands and on the mainland. A statistical
 analysis based on a modified before-after control-impact approach found no
 difference in indices of site fidelity or diving intensity between the
 seismic area and two control areas. Thus, we found no effect of seismic
 activity on movements 
 and diving behavior of molting Long-tailed Ducks. These results should be
 evaluated carefully, however, as logistical and ecological factors limited
 our ability to detect more subtle disturbance effects. We recommend
 additional studies on other bird species to fully 
 understand the effects of underwater seismic testing. 
 Richardson's ground squirrels (Spermophilus richardsonii) do not communicate
 predator movements via changes in call rate
 David R. Wilson and James F. Hare
 Can. J. Zool./Rev. Can. Zool. 81(12): 2026-2031 (2003) 
 The call rate of repetitive alarm calls produced by Richardson's ground
 squirrels (Spermophilus richardsonii) conveys the extent of threat during
 predator encounters. It remains unknown, however, whether changes in call
 rate communicate predator movements. That is, does an increasing call rate
 indicate an approaching predator and a decreasing rate the opposite? We
 presented free-living squirrels with moving predator models and recorded
 their responses. Vigilant behaviour increased more when predators approached
 versus retreated, suggesting that squirrels recognize the changes in threat
 associated with predator movements. Squirrels rarely produced alarm calls
 during these encounters, however, suggesting that squirrels do not rely
 entirely on alarm ocalizations to assess the threat posed by potential
 predators. Receivers of manipulated calls did not respond differentially to
 alarm calls containing an increasing or decreasing rate of syllable
 production. Thus, while rate may encode information about the extent of
 threat, Richardson's ground squirrels do not communicate predator movements
 via changes in call rate. 

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