01597nas a2200145   4500008004100000245008000041210006900121300001200190490000800202520108800210100001801298700001601316700001501332856010401347       1997                        eng d00aFall point counts: Time of day affects numbers and species of birds counted0 aFall point counts Time of day affects numbers and species of bir  a94 -1000 v1003 aTime of day is known to affect results of avian surveys during breeding season and winter. Because little is known of the effects of time of day on avian surveys conducted between breeding season and winter, we conducted a series of point counts during early morning, midmorning, midafternoon, and late afternoon from mid September through early December. Numbers of birds counted and species richness differed by time of day and season, but only 1 of 16 time-of-day differences in numbers of birds counted was significant (P &lt; 0.05) because the number of birds counted fluctuated widely during the study. Point-count data collected during early morning and late afternoon produced similar avian assemblages, but significantly different (P &lt; 0.05) from assemblages created by data collected during midmorning and midafternoon periods, which were significantly different (P &lt; 0.05) from each other. Caution is urged when using point-count data collected at different times of the day in the fall to describe avian abundances and compare avian assemblages in the Plains States1 aO'Leske, D.L.1 aRobel, R.J.1 aKemp, K.E.  uhttp://knz.lternet.edu/content/fall-point-counts-time-day-affects-numbers-and-species-birds-counted