Results of generalized linear mixed models that included the pre, during, and post periods for our three species: Black-capped chickadees (N = 50 trials), tufted titmice (N = 39 trials), and white-breasted nuthatches (N = 44 trials).

For each species we separately analyzed the number of mobbing calls produced per 10-minute interval (binomial distribution), the number of notes produced per 10-minute interval (negative binomial distribution), and the number of notes per call (Gaussian distribution).</p

Number of black-capped chickadee D notes per <i>chick-a-dee</i> call.

Data are collapsed over the pre, during and post periods and presented as a function of (a) predator stimulus modality and (b) noise presence. Asterisks indicate significant differences (* = p < 0.05) that were obtained using the anova function in R 1.4.1717. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values.</p

Results of generalized linear mixed models that include only the pre and during-stimulus periods for our three species: Black-capped chickadees (N = 50 trials), tufted titmice (N = 39 trials), and white-breasted nuthatches (N = 44 trials).

For each species we separately analyzed the number of mobbing calls produced per 10-minute interval (binomial distribution), the number of notes produced per 10-minute interval (negative binomial distribution), and the number of notes per call (Gaussian distribution).</p

Spectrographic representation of the alarm calls of our three focal species.

From left to right, brackets and labels indicate the chick-a-dee mobbing call of the tufted titmouse, Baeolophus bicolor, the quank alarm calls of the white-breasted nuthatch, Sitta carolinensis, and the chick-a-dee mobbing calls of the black-capped chickadee, Poecile atricapillus. (Hanning window, DFT = 512, 3dB filter bandwidth = 124 Hz).</p

Number of approaches within 5 meters of the feeding platform.

Data are presented as a function of (a) predator stimulus modality, noise presence, and period, (b) of species (including only the pre and during periods), and (c) of species (including the pre, during, and post periods). An approach was defined as a bird crossing a boundary and landing within 5m of the feeding platform. Asterisks indicate significant differences (p < 0.05) that were obtained using the anova function in R 1.4.1717. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values. All data points are shown in (a), jittered along the x-axis for visibility, while only outliers are shown as points in (b) and (c).</p

Total number of tufted titmouse <i>chick-a-dee</i> calls produced per 10-minute interval.

Number of calls are presented as a function of (a) predator stimulus modality (for pre and during period only), (b) predator stimulus modality (for pre, during and post stimulus periods), and (c) trial period. Asterisks indicate significant differences (* = p < 0.05 | ** = p < 0.01 | *** = p < 0.001) that were obtained using the anova function in R 1.4.1717. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values. Individual data points are jittered along the x-axis for visibility.</p

Total number of white-breasted nuthatch quank notes produced per 10-minute interval.

Note production is presented as a function of predator stimulus modality and noise presence. The number of notes per 10 minutes. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values.</p

Total number of white-breasted nuthatch <i>quank</i> calls produced per 10-minute interval.

Calls are presented as a function of predator stimulus modality, noise presence and period (all trial periods included). Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values. Individual data points are jittered along the x-axis for visibility. Asterisks indicate significant differences (* = p < 0.05) that were obtained using the anova function in R 1.4.1717.</p

Total number of black-capped chickadee <i>chick-a-dee</i> calls produced per 10-minute period.

Data are presented as a function of (a) period and noise presence and (b) predator stimulus modality (including pre, during and post periods). Calls of two or more chick-a-dee notes in a series were included. Asterisks indicate significant differences (* = p < 0.05) that were obtained using the anova function in R 1.4.1717. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values. Individual data points are jittered along the x-axis for visibility.</p

Total number of black-capped chickadee D notes produced per 10-minute interval.

Note production is presented as a function of (a) predator stimulus modality and period and (b) noise presence (includes pre, during, and post periods). Asterisks for (a) indicate significant differences (* = p < 0.05 | ** = p < 0.01) that were obtained using the anova function in R 1.4.1717. Boxes represent interquartile ranges, whiskers represent range, and central lines indicate median values. Individual data points are jittered along the x-axis for visibility. Two outliers with counts above 600 under the visual condition in the post period were not included in the graphs for ease of interpretation but were included in the statistical analysis.</p