Ord met Alexander Wilson in the summer of 1811, and accompanied him on two collecting expeditions (each four weeks duration) to Cape May, New Jersey, during the spring migration seasons of May 1812 and May 1813.

Through the zeal and activity of this gentleman I succeeded in procuring many rare and elegant birds among the sea islands and extensive salt marshes that border that part of the Atlantic ; and much interesting information relative to their nests, eggs, and particular habits.

"[11]The letter-press for volume 8 of American Ornithology (1814) was complete by August 1813, but Wilson's "great anxiety to conclude the work, condemned him to an excess of toil, which, inflexible as was his mind, his bodily frame was unable to bear.

[15] He was a reviewer of three influential papers authored by Charles Lucien Bonaparte in 1824 and 1825, which included the original taxonomic descriptions of Wilson's Storm Petrel (Procellaria Wilsonii)[15][16] in 1824, and Transvolcanic Jay (Aphelocoma ultramarina), and Yellow-winged Cacique (Cassiculus melanicterus) in 1825.

[20] His publication about "An account of an American species of the genus Tantalus or Ibis" (1817) was the first account of the Glossy Ibis (Plegadis falcinellus) in the United States,[21] as noted by Bonaparte in his quasi-continuation of Wilson's American Ornithology (1833):"The credit of having added this beautiful species [Plegadis falcinellus] to the fauna of the United States is due to Mr. Ord, the well known friend and biographer of Wilson, who several years ago gave a good history and minute description of it in the Journal of the Academy of Philadelphia, under the name Tantalus mexicanus?

His excellent memoir would have been sufficient to establish its identity with the species found so extensively in the old world, even if the specimen itself, carefully preserved in the Philadelphia Museum, did not place this beyond the possibility of doubt.