Breeding Codes

Breeding Codes used in the Second Pennsylvania Breeding Bird Atlas

Breeding behaviors were summarized into a set of codes to record evidence of nesting, ranging from the simplest detection by sight or sound through confirmation of active nests and fledged young. Birds observed in breeding habitat and within their particular breeding season were placed in one of four categories based on the level of breeding evidence:  Observed outside breeding habitat, or Possible, Probable, or Confirmed breeding evidence.  Species distribution maps reflect these breeding categories.  Specific behaviors were identified by field observers in 16 categories, listed below.  These codes closely follow standards set out by the North American Bird Atlas Committee (Laughlin et al. 1990).

Observed  (These non-breeding codes were not mapped or counted toward block coverage.)
Possible Breeding  (The lowest entry for breeding behavior.)
Probable Breeding Confirmed Breeding

North American Atlas Committee Source
Laughlin, S. B., J. R. Carroll, and S. M. Sutcliffe. 1990. Standardized breeding criteria codes: recommendations for North American Breeding Bird Atlas projects. in Handbook for Atlasing North American Breeding Birds (C. R. Smith, Ed.). Vermont Institute of Natural Science, Quechee, VT.