<p>Oak Titmouse (Baeolophus inornatus) resident from southern Oregon south to Baja California. Preferred habitats include live oaks and deciduous growth.
Reference &lt;a href="<a rel="nofollow" class="external free" href="http://identify.whatbird.com/obj/138/_/Oak_Titmouse.aspx">http://identify.whatbird.com/obj/138/_/Oak_Titmouse.aspx</a>" rel="nofollow"&gt;identify.whatbird.com/obj/138/_/Oak_Titmouse.aspx&lt;/a&gt;
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Whilst I was observing them trying to build the nest, they were severely harrassed by a female Nuttall's Woodpecker.  I have been back to this potential nesting hole many times in the last 4 weeks but the titmice obviously chose to nest elsewhere.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/32541690@N02">Alan Vernon</a>
CC BY 2.0
<a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a>: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/32541690@N02/5719848631">Oak Titmouse leaving the nesting hole</a>