780 
THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 4. December 2012 
P rey remains 
n 
n 
... 
16-30 1-15 
Jun Jul 
(301) (319) 
15-31 
Jul 
(257) 
1-15 
Aug 
(75) 
(B) 
1 
«. 0.9 
B 
^ 0.8 
Direct observations 
m 
nn 
3 0.7 
CO 
£ 0.6 
J 0.5 
o 0.4 
J 0.3 
I °’ 2 
£ 0.1 
"ssSaWlflfs 
® Adult mammal I Subadult mamma. ■ Adult bW □ Avian young of the year 
British Columbia by prey rem^n"'(A) an^dirL'c- , .‘ohsJrv' 1 J '' r ’ 1995-2010 at Coo Per s Hawk nests in Victor 
penod is in parentheses. Prc-incubation. incubation nestlin,. ... i n , c 1 . number ot 'dcntifiable items recorded in each tit 
to late-May, late-May to late-Junc, and July to August respectively § S,ageS OCCUr in March to early-April. mid-Ap 
(Rosenfield et al. 2010, Sonsthagen et al. 2012). 
Larger and less agile prey are taken by Cooper’s 
Hawks in some eastern populations where Coo¬ 
per s Hawks are larger (Rosenfield et al ^OIO) 
Roth and Lima's (2003) data mostly (141 of 179 
attacks) were observations of wintering female 
hawks in an eastern population. Wintering male 
and female Cooper's Hawks capture House 
Sparrows in Victoria, but males do so more than 
females (ACS, unpubl. data) 
Ours is the firs, study ,o' describe introduced 
species as a major component of the diet of urban 
breeding ( ooper s Hawks. Introduced species are 
noun (or causing damage to native ecosystems 
and species (e.g.. Mack et aJ. 2000, Chace and 
a sh 2006), but they can provide potential 
benefits to ecosystems (Schlaepfer et al. 20111. 
he mttoduced bird species in our study area are a 
benefit as they provide a valuable resource for 
native, breeding Cooper’s Hawks in Victoria, 
ntroduced bird species, particularly House Spar- 
tows and European Starlings, are predominant 
?QOsI ,na ' n many cUies (c *8” Marzlu,Y el aL 
). and it appears these species are important 
