Like most wild birds, Buffleheads are difficult to tell apart. However, if anything, it’s the females that show the most variation in their plumage, occasionally allowing individual identification. Yearling males, which are often considered indistinguishable from females in the field, also show considerable variation though their patterns change as moult progresses. Therefore, it’s difficult to study individual behaviours and the complex social structure of Buffleheads. (They are monogamous and return with high fidelity to their summer and winter residences. ).
Once in a long while, however, a distinctive individual shows up, permitting the field biologist to make hay, so to speak, by logging their every movement and dive. That was the case with VAL, a distinctive female who I was fortunate to observe over three winter seasons from November 21st, 2005 to December 15th 2007 (when she was accidentally killed by the resident “Burgomeister” gull).