Saborse and Renne • HISTORIC PRESENCE AND ABSENCE OF PREDATORS 
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FIG. 3. Representative spectrograms of ‘chick-a-dee’ calls from (A) Beaver Creek State Park, (screech-owls present) 
and iB) Ford Nature Center (Mill Creek Metroparks), Ohio (screech-owls absent). 
exposed to this predator. Achieving sympatry with 
a predator is likely to result in quick spread ot 
threat-appropriate calls, but the time necessary for 
this is not trivial for small populations threatened 
with extirpation. The rapidity with which this 
transmission occurs can be accelerated by linking 
naive populations lacking fitness-related vocali¬ 
zations with those ‘culturally significant units' 
having them (Ryan 2006). This suggests manage¬ 
ment which increases population connectivity can 
he of strong conservation value to many songbirds 
'n decline by maximizing population growth 
Potential, which in part is driven by facilitating 
transmission of behaviors of high adaptive value. 
ACKNOWLEDGMENTS 
We express gratitude to J. N. Mager ot Ohio Northern 
University for lending recording equipment and for com¬ 
ments on this project. We also thank A. W. Jones of the 
Cleveland Natural History Museum for lending us a stuffed 
Eastern Screech-Owl model. R C. Jones and R. J. Novotny 
of Mill Creek Metroparks, and many other park managers as 
well as experienced ornithologists are thanked lor commu¬ 
nicating their knowledge of the long-term, detailed screech- 
owl records throughout our study region. J. D. Usis and F. P. 
Diggins of Youngstown State University (YSU) are thanked 
lor providing insightful comments as this project developed 
and T. P. Higgins of YSU is thanked for detailed comments 
on an earlier draft. The assistance from these people was 
invaluable to our research. We appreciate the timely 
approval of YSU's 1ACUC animal use protocol (# 05-10), 
P. j. Kasvinsky (YSU) for funding of this project (URC # 07- 
10). and the U.S. Fish and Wildlife Service and Ohio 
Division of Wildlife for scientific collecting permits to 
capture Black-capped Chickadees (#MBI7l55A-0and# 11- 
363, respectively). 
LITERATURE CITED 
AVEY, M. T.. M. Hoeschele. M. K. Mosctcki, L. L. 
Bloomfield, and C. B. Sturdy. 2011. Neural 
correlates of threat perception: neural equivalence of 
conspecific and heterospecific mobbing calls is 
learned. PLOS ONE 6(8):e23844. DOF 10.1371/ 
joumat-pone.0023844. 
Baker. M. C. and A. M. Becker. 2002. Mobbing calls of 
Black-capped Chickadees: effects of urgency on call 
production. Wilson Bulletin 114:510-516. 
Bartm ess-Lev .asset r, J.. C. L. Branch. S A Browning. 
J. L. Owens, and T. M. Freeberg. 2010. Predator 
stimuli and calling behavior ot Carolina Chickadees 
