OB Observed
O Species (male or female) observed during the breeding season but no evidence of breeding observed.
PO Possible
H Species (male or female) observed in suitable nesting habitat during its breeding season
X Less than 7 singing males present in suitable nesting habitat during the breeding season
PR Probable
P Pair observed in suitable nesting habitat during its breeding season
T Permanent territory presumed through defense (e.g., chasing of other birds, or song or display at the same location on at least 2 occasions a week or more apart)
C Courtship behavior or copulation observed
N Visiting of probable nest site
A Agitated behavior or anxiety calls from adult(s)
B Nest building by wrens or excavation of holes by woodpeckers. (NOTE: nest construction by other species falls under the Confirmed - NB category).
M 7 or more males singing in suitable nesting habitat during the breeding season
CO Confirmed
NB Nest building by all species except wrens and woodpeckers
PE Physiological evidence of breeding: brood patch or egg in oviduct (based on bird in hand)
DD Distraction display or injury feigning by adult
UN Used nest or eggshells found. CAUTION: These must be carefully identified if the record is to be accepted.
FL Recently fledged young (of altrical species) incapable of sustained flight, or downy young (of precocial species) restricted to the natal area by dependence on adults or by limited mobility.
ON Occupied nest: Adults entering or leaving nest (includes high nests or nest holes, the contents of which cannot be seen) OR adult incubating or brooding
AY Attending young: Adult carrying fecal sac or food for young, or feeding recently fledged young
NE Nest with egg(s)
NY Nest with young seen or heard