Family-level detection probabilities by method
In BC, models supported an effect of methodology on detection for only 6 of the 14 families examined. These were: finches (Fringillidae), sparrows (Passerellidae), warblers (Parulidae), kinglets (Regulidae), thrushes (Turdidae) and corvids (Corvidae; Figs S1-S3). All six families were better detected by ARUs. Kinglets, warblers and thrushes showed an interaction between methodology and hours after sunrise: detection probability declined over the morning for point counts but remained consistently high for ARUs (Fig. S2). Warblers, thrushes and corvids showed an interaction between methodology and canopy cover: detection probability was more variable over the range of canopy cover for point counts than for ARUs (Fig. S3).
In Chile, detection models for all 11 families examined supported a methodology effect, with a higher detection probability in point counts than in ARUs (Figs. S4-S6). Of these, six families showed an interaction between methodology and date: ARU detection probability for swallows (Hirundinidae), hummingbirds (Trochilidae), woodpeckers (Picidae), wrens (Troglodytidae), and parakeets (Psittacidaewas either lower early in the monitoring period or exhibited a mid-season dip. The detectability of ovenbirds (Furnariidae), showed a mid-season dip in point counts but not ARUs (Fig. S4). Ovenbirds additionally had lower detection probability for ARUs under conditions of high canopy cover. Swallows were better detected by point counts in the mid-morning; wrens were more poorly detected by ARUs in the early morning (Fig. S5).