Ab   Abundant: Should see on every trip in the proper habitat.
C     Common: Should see on 3 out of 4 trips in the proper habitat
FC   Fairly Common: Should see on 2 out of 4 trips in the proper habitat
U     Uncommon: Should see on 1 out of 4 trips in the proper habitat
R     Rare: Should see on 1 out of 10 trips or less in the proper habitat
Ca   Casual: Not expected annually and includes out-of-season occurrences for the region
Ac   Accidental: Generally refers to 3 records or fewer for the region
?     Questionable: Status not entirely known
(ir)   Very irregular. May not occur year after year
(L)   Occurs locally within a limited geographical or altitudinal range
(H)   Historical records only (prior to 1974)
(ab) Completely absent throughout some geographical areas in the Trans-Pecos but observed regularly in others
BB   Big Bend country. Generally the southern three quarters of Brewster and Presidio counties
NO   Northern Trans-Pecos (from the Davis Mountains north)
VA   Val Verde County and the southeastern Trans-Pecos
DM   Davis Mountains
GU   Guadalupe Mountains
CH   Chisos Mountains
MT   Normally found in the major mountain ranges
RG   The Rio Grande watershed

Seasonal Definitions