SONG OUTPUT AS A POPULATION ESTIMATOR - EFFECT OF MALE PAIRING STATUS

Variation in song output of paired and unpaired, male Ovenbirds (Seiur us aurocapillus) and Kentucky Warblers (Oporornis formosus) was examin ed and its effect on estimates of population density derived from the spot-map survey technique. Song output during late-May and early-June in central Missouri averaged 3.5 times greater for 17 unpaired (1.74 s ongs/min) than 15 paired Ovenbirds (0.50 songs/min) and 5.4 times grea ter for 16 unpaired (2.22 songs/min) than 26 paired Kentucky Warblers (0.41 songs/min). Ten spot-map visits to known populations detected al l unpaired males but missed 50% of paired male Ovenbirds and 35% of pa ired male Kentucky Warblers. A reliance on singing male contacts durin g spot-map surveys resulted in underestimation of population density a nd could confound assessments of habitat quality.