Melanie, it surprised me too ... I'm assuming it's mouth is open like that when it's making those rattling calls.
More photos from this afternoon ....
Tufted Titmouse ......................................... Northern Cardina
Myrtle Warbler? .......................................... Belted Kingfisher
Mourning Dove
Eastern Bluebird? I don't EVER see Bluebirds and there were a few around this afternoon, flitting in and out of trees on a neighbors property across the water from me.
