WINNOWING COUNTS AS A MEASURE OF WILSON'S SNIPE BREEDING POPULATIONS 
Chandier S. Robbins 
U. S. Fish and Wildlife Service 
Since no adequate technique had been perfected for the censusing 
of Wilson's Snipe on their breeding grounds, the writer was assigned 
to make a study of their winnowing activity as an indicator of abune- 
dance during the breeding season. The area selected for the investiga- 
tion was Manitoulin Island, located between Lake Huron and Georgian 
Bay, Ontario. Investigations were carried out in this area: from June 
1 to 23, 1952. Mr. Harry Lumsden and other biologists of the Ontario 
Department of Lands and Forests had already conducted studies of 
woodcock and grouse on this island, and supplied valuable information 
on the distribution and abundance of snipe during the spring migration 
period. I wish to thank Dr. C. H. D. Clarke, Supervisor, Wildlife 
Management, Department of Lands and Forests, Toronto, and Dr. V. FE. F. 
Solman, Chief Biologist, Canadian Wildlife Service, for helpful sug- 
gestions and for many courtesies extended to me prior to and during the 
investigations. 
The most extensive observations were made in an irregular-shaped 
marsh of about fifteen acres, located one-half mile east of the Barrie 
Island bridge, or about one mile northwest of the Gore Bay airfield in 
Gordon Township. Three pairs of snipe were recorded regularly in this 
marsh throughout the period of the study. Although there is danger of 
obtaining atypical results when working with such a small sample, in- 
formation gathered from other areas on Manitoulin Island did not vary 
appreciably in any respect from data obtained at the Barrie Island 
bridge. 
The advantages of the particular area chosen for study were the 
relatively small size of the marsh, and its accessibility by road. 
Except during periods of high wind, all three winnowing males could 
easily be heard all the time they were performing, and there was no 
danger of interference by other males, as there were no other nesting 
areas within two miles. It was frequently possible to distinguish the 
three males by the area each covered, the number of "winnows" per 
minute, the length of each winnowing call, a peculiar quality of the 
winnowing sound of one individual, or the position of the answering 
female (whose customary ground position in the evening and early morn- 
ing was usually not under the area covered by the performing male). 
Time of Day 
Snipe were heard winnowing over their nesting grounds at all 
hours of the day and night, but a definite peak of activity occurred 
hy 
