Just saying the name Baird's Sandpiper in Newfoundland creates a fog of ID mystery. This is partly because of the limitations of Field Guides and the difficulty in capturing the true nature of a Baird's Sandpiper with a photograph.
The ID problem starts when you live in Newfoundland where Baird's Sandpiper is a rarity with 1-5 per year but Semipalmated and White-rumped Sandpipers are common. The Field Guides advertise the scaly back pattern of the Baird's Sandpiper is typically the center-focus of identification. However, numerous juvenile Semipalmated and White-rumped Sandpiper migrating through Newfoundland and Labrador also have "scaly backs".
This Baird's Sandpiper was at Long Beach, Cape Race, Avalon Peninsula, Newfoundland on 16 Sept 2016.
Semipalmated Sandpiper (the two photos below) on the same beach for comparison.