Study shows impact of birders/hikers on birds

A study of how human voices effect birds was conducted recently in Peru. Their findings, published in Biotropa: Journal of Tropical Biology and Conservation included:
>human voice noise resulted "in decreased vocalizations (37% decline) and decreased physical sightings (44% decline)."
>of conservation concern: "As vocalization is involved in territory defense, breeding behavior, and predator detection, strong noise responsiveness indicates potential harm for birds. Insectivores were the most affected bird guild, raising conservation concerns, as insectivorous birds are sensitive to habitat modification"

I have found the issue of 'birder impact' to be a hot topic with many serious birders who maintain that their birding has no deleterious effects on birds. I got in hot water on the Colo birding listserve a few years ago for expressing my concern about birder impact, in that instance the subject specifically addressed birders damaging habitat while pursuing rare birds. I was flat told that birders in Colorado don't do that. What a crock--I have personally observed birders trampling habitat to see rarities in Colorado on more than one occasion. This research adds another dimension, plus some scientific research, to the issue of how birders impact birds (and their habitats).

The research is discussed in an article "Hiking quietly benefits birds... and birders"SeEtta