We have copied the abstract below and attached a pdf from recent paper
published in The Canadian Field-Naturalist, which is a peer-reviewed

Citation: Elliott, Kyle H., Paul A. Smith, and Victoria H. Johnston. 2010.
Aerial surveys do not reliably survey boreal-nesting shorebirds. Canadian
Field-Naturalist 124(2): 145-150.

Abstract: Aerial surveys have been used as a method for surveying
boreal-nesting shorebirds, which breed in difficult-to-access terrain;
however, the fraction of breeding birds observed from the air is unknown. We
investigated rates of detection by conducting simultaneous air and ground
surveys for shorebirds at three sites in the boreal forest of the Northwest
Territories, Canada, in 2007. Helicopter surveys included both pond-based
surveys and where the helicopter flew around the perimeter of each wetland
and transect-based surveys where observers recorded birds seen on line
transects.  Ground surveys involved intensive observation, territory mapping
and nest searching in 5 square kilometers of plots over a period of 5-6
weeks. Shorebird densities observed from the helicopter were highest near
large bodies of water. No shorebirds were observed over closed forest
despite breeding densities on ground surveys being highest in closed forest.
Detection rates were very low, varied among species and aerial survey types,
and were inconsistent over time. Ground-based observations showed that the
shorebirds often did not flush in response to the helicopter passing
overhead. Owing to poor rates of detection, we conclude that helicopter
surveys are not an appropriate method for surveying breeding shorebirds in
boreal habitats, but may have some utility for monitoring birds' use of
stop-over locations.

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Ron Pittaway and Jean Iron

Minden and Toronto, Ontario