A phantom road experiment reveals traffic noise is an invisible source of habitat degradation.
Decades of research demonstrate that roads impact wildlife and suggest traffic noise as a primary cause of population declines near roads. We created a "phantom road" using an array of speakers to apply traffic noise to a roadless landscape, directly testing the effect of noise alone on an entire songbird community during autumn migration. Thirty-one percent of the bird community avoided the phantom road. For individuals that stayed despite the noise, overall body condition decreased by a full SD and some species showed a change in ability to gain body condition when exposed to traffic noise during migratory stopover. We conducted complementary laboratory experiments that implicate foraging-vigilance behavior as one mechanism driving this pattern. Our results suggest that noise degrades habitat that is otherwise suitable, and that the presence of a species does not indicate the absence of an impact.
Department of Biological Sciences, Boise State University, Boise, ID 83725; Intermountain Bird Observatory, Boise State University, Boise, ID 83725; heidiware@boisestate.edu jessebarber@boisestate.edu.
Heidi E
HE
Ware
Department of Biological Sciences, Boise State University, Boise, ID 83725; Peregrine Fund, American Kestrel Partnership, Boise, ID 83709.
Christopher J W
CJ
McClure
Department of Biological Sciences, Boise State University, Boise, ID 83725; Intermountain Bird Observatory, Boise State University, Boise, ID 83725;
Jay D
JD
Carlisle
Department of Biological Sciences, Boise State University, Boise, ID 83725; heidiware@boisestate.edu jessebarber@boisestate.edu.
Jesse R
JR
Barber
D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001336:Automobiles; D003247:Conservation of Natural Resources; D017753:Ecosystem; D007061:Idaho; D008954:Models, Biological; D009624:Noise, Transportation / Q000009:adverse effects*; D020308:Songbirds / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*
foraging-vigilance trade-off; habitat degradation; perceived predation risk; songbird migration; traffic noise pollution