The Yellow-bellied Sapsucker is a very unusual woodpecker with distinct male, female, and juvenile plumages as shown in the accompanying photos. Adult males have a red throat, a black bib, and a slightly yellow-tinted breast; adult females have a white throat, black bib, and yellow-tinted breast. Juveniles have a gray throat and breast for much of their first year.
Juvenile birds that arrive in Florida in the fall are usually in their drab juvenile plumage. Both juveniles and adults will be molting or begin molting and their new plumage will be much brighter. By March all are brighter than they were when they arrived in the fall. The black-and-white barring on the Yellow-bellied Sapsucker’s back and wings has significant adaptive value in allowing the sapsucker to blend in with the light and shade filtering through tree limbs and leaves. The black bib also has specific adaptive value in dissociating the bird’s head from its body, making a sapsucker intent on excavating sap wells more difficult to spot.
The rows of sap wells shown in the photo on the palm trunk are all horizontal for a reason. Palms don’t have all their active vessels just under the bark as other trees do, but have them dispersed throughout the trunk. The bird was a juvenile that made the rows of holes as it looked for sap, but rarely got it. It made lots of “dry” holes and did not return in subsequent years.