These pics were taken on December 20, 2006 in the Coastal Plain near Houston and Galveston, Texas; it is a LBBG-type but - assuming that it is a second-cycle - shows some heuglini features, in that:-
1) the bill has a cleanly-demarcated dark tip (typical of heuglini in their 2nd cycle, but for LBBG only in its 3rd cycle)
2) most of the underwing coverts are white (again typical of heuglini in their 2nd cycle, but for LBBG only in its 3rd cycle)
3) the head/neck speckling is strongly concentrated on the nape (typical for heuglini leaving a whitish head with dark eyemask, while LBBG has more visible - denser and thinner - dark markings on the crown and ear-coverts, connecting the dark rear-eye area to the hindneck streaking).
Note also the odd molt boundries in the secondaries and tail - this is typical for some heuglini and nominate fuscus LBBG, but rare (?) for graellsii/intermedius:
