Yellow-bellied Sapsuckers get most of their nutrition from sap which they gather in sap wells that they industriously bore and maintain. Perfectly logical to call them sapsuckers in my opinion. And, since they have a yellow belly also logical to name them Yellow-bellied Sapsucker. All in all, a fitting name for a strikingly marked, industrious hard working bird that survives the extremes of wild forests. One reason they survive in forest settings, in fact thriving in successional forests, is they are not afraid to get out of their comfort zone and make use of a variety of foods.
Yet, despite these virtues, their name is a way to throw some shade – “You yellow-bellied sapsucker. You coward”. Yellow-bellied Sapsuckers are not cowards. Far from it as explained above. So how did this connection come about.
Their only fault seems to be having a yellow-belly and the color yellow in many cultures being associated with yellow, sickly complexions. An example was the derogatory description used to describe people that lived around Lincolnshire, England: “Yellow-belly, A person born in the Fens of Lincolnshire (From the yellow, sickly complexion of persons residing in marshy situations.)”
Also over the ages, and especially in the Middle Ages, for reasons usually not understood or long forgotten, the color yellow came to symbolize human weaknesses and immorality. At different times being alternatively connected to heresy, jealousy, treachery, sin and gutlessness. Often, the outward and visible expression was forced wearing of a variety of yellow tunics and badges – yellow bellies.
It seems that the direct name calling connection between the bird and cowards originated in American cowboy vernacular. Cowboys took the expression beyond someone being sickly to someone being being cowardly. A particularly bad form of sickly in the view of cowboys. In a typically practical cowboy way they dropped the abstract and went directly to an easy to express visual. A yellow-bellied bird with a weird behavior of sucking sap and a weird sounding name brought a metaphor to life. A turn of phrase was made literal, and it didn’t hurt that it was great phrasing for cowboy movie & cartoon scripts.
Yellow-bellies (does sound disparaging) have actually increased in overall numbers. Not because of some concerted management effort, but because in some areas across their range, old-growth forests that were heavily lumbered have been replanted. These forests are now successional forests which are a favorite for sapsuckers. Lot’s of sap flow. It seems they are getting the last word.