SHORT COMMUNICATIONS 
631 
(Table 1). Inside nest diameter was close to 
average for Least Bell's Vireos and at the low 
end of the range for White-eyed Vireos. Nest depth 
and cup height were greater than average for Least 
Bell's Vireos but near average for White-eyed 
Ynens. This may indicate that females affect these 
nest parameters during nest building. Alternatively, 
since White-eyed Vireos are on average larger 
ifemale; 11.7 g. range = 10.5-13 g. n = 6;Hoppet 
al. 1995) than Least Bell's Vireos (combined sex: 
8.5 g. range = 7.4-9.8 g ,n — 33; Kus et al. 2010). 
the nest depth and cup height may be a reflection of 
the female's size rather than any sex-specific 
influence on nest dimensions. 
Hopp el al. (1995) reported that upon fledging, 
young White-eyed Vireos appear similar in 
plumage coloration to adults, but are less yellow. 
They also note the iris is brownish in White-eyed 
Vireos up until -November of the hatching year, 
hie (1997) notes that hatch-year and second-year 
birds display a brownish-gray to grayish iris 
through February and after-hatch-year birds 
usually display a white or white with slight 
grayish wash iris (Aug-Jul). It will be interesting 
to see what combination of Least Bell's Vireo and 
female White-eyed Vireo was in a situation in 
which there were no potential conspecific mates 
which may have changed her threshold(s) of 
responsiveness to cues in the environment. 
ACKNOWLEDGMENTS 
We thank Lisa D. Allen for photography/video docu¬ 
mentation and Kimberly Ferrce for corroborating the 
sighting. We also thank Sucllen Lynn, Kathleen Longshore, 
Roger L. Hothem. and two anonymous reviewers for 
helpful comments on the manuscript. Funding was provided 
by the U.S. Army Corps of Engineers. Los Angeles District. 
The use of trade, product, or firm names in this publication 
is for descriptive purposes only and does not imply 
endorsement by the U.S. Government. 
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White-eyed Vireo morphological characteristics 
are expressed in the adult plumage should the 
hybrid young return to the study area in future 
years. It will also be interesting to see if they 
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Least Bell’s Vireos and White-eyed Vireos 
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White-eyed Vireos have a more distinct facial 
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