Believe this is an immature Chipping Sparrow. Want to thank Tom Murray and James Fox (eBird) for their help at identifying this sparrow.
Best viewed in 'original' size.
Nikon D800
,AF-S VR Nikkor 70-200mm f2.8G with TC-20 E II 1/250s f/5.6 at 600mm iso1000
UnCropped DX Image Size Reduced for Internet Viewing
full exif