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THE WILSON JOURNAL OF ORNITHOLOGY • Vol 123. No. 2. June 2011 
Le ^’ n f beh ^ ior reIurn time for al lc ast two Lesser Prairie-Chickens following an accipiter. other or unknown 
p. i * onA-Tonnsftf™ amer " Swainson s Hawk, and unknown raptor encounters at leks in the Texas Southern High 
;’ r; ^ 0 ?, 8 - B ° k xes represenl ln,erc l uartile range about the median. Whiskers represent the most extreme 4 - ~ 
that« no more than the range X the interquartile range from the box. Asterisks represent outliers in the th~ 
falcons repeatedly dove at prairie-chickens. The 
initial response in all falcon encounters was for 
prairie-chickens to squat and stay on the ground; 
however, after repeated swoops by the falcon, a 
few eventually flushed in two encounters and 
were recorded as partial flushes. 
Lesser Prairie-Chickens are apparently able to 
differentiate risk posed by different avian preda¬ 
tors and respond accordingly. Raptors elicited 
some type of response in 85% of encounters 
whereas only 9% of raven encounters elicited a 
respon.se (X, 1 = 138, P < 0.001). Mean (± SD) 
time for at least two prairie-chickens to be 
displaying at leks following a raptor encounter 
was 4. r _ ± 5.5 min. Return times were different 
following encounters involving different raptor 
species (Kruskal-Wallis Rank Sum Test xj - 
11.895, P = 0.036; Fig. 3). 
DISCUSSION 
Sage- and prairie grouse spend a substantial 
amount of time on leks (typically 3-4 hrs/day. 
Hagen and Giesen 2005) during the spring. Their 
congregation and exposure could lead to increased 
predation risk (Lehmann 1941, Hart/.ler 1974 
Schroeder and Baydack 2001). Our data suggest 
raptor predation on Lesser Prairie-Chickens at 
leks is uncommon. We did not observe any 
successful predation events at leks despite 650 hrs 
of data from when Lesser Prairie-Chickens were 
on leks. 
Our results 
studies of lekk 
are similar to those from other 
ing species as successful predation 
events on leks were rare or absent (Berger el al. 
1963. Moran 1966, Haukos and Broda 198')) 
Encounters classified as predation attempts in our 
study were rare (0.02 attempts/hr). This suggests 
use of a lek mating system may limit predation 
events and may be an efficient anti-predator 
strategy (Boyko et al. 2004). 
Northern Harrier encounters peaked during die 
2-week interval of 23 March to 5 April, after 
which they began migrating from the study area 
(Fig. I; Behney 2009). Buteonine hawk encoun¬ 
ters were low throughout the lekking season hit 
peaked during the interval starting 6 April, which 
corresponded to migrants moving through the ^ 
while some wintering hawks were still pi esCflI 
(Behney 2009. Preston and Beane 2009 ). Swain- 
son’s Hawk encounters were low throughout ihe 
season but peaked during the interval starting - 1 ' 
April. This corresponded to arrival of Swainson > 
Hawks migrating from the southern hemi 1 #'; 
(England et al. ^1997, Behney 2009) and estab¬ 
lishment of breeding territories in the stud) ; *r.- 
The period of peak female attendance at ,l:L ‘ 
corresponded to dramatic decreases in 
encounters at leks (Fig. 1). Haukos (198" 
reported a similar observation that peak 
Lesser Prairie-Chicken attendance at leks oc¬ 
curred just after most raptors had migt" 1 * 1 ' 
through the area. 
Lesser Prairie-Chicken responses to predan^ 
attempts appear to correspond to the hunt |n =- 
strategies of different raptor species. 
Harriers and buteo hawks (including Swains^ s 
