About Canada Goose Collars
Canada Geese are widely marked with neck collars and colored leg bands. Canada Geese are marked with either 3 or 4 digit collars. Fewer characters (usually 2) are sometimes used for collars used to mount radio transmitters on birds. Small subspecies of Canada Geese including Richardson's, Cackling, and Aleutian Geese have a smaller collar with 3 digits (also see Arctic Goose Joint Venture). Large Canada Geese have 4 digits on the collar except in the Atlantic Flyway where a revolutionary flexible "bib-type" collar with 3-digits is used. The "bib-type" collar was developed to reduce icing problems for geese that winter in northern areas.
3 DIGIT COLLARS
Collars with 3 digits include yellow and orange collars from the Arctic Goose Joint Venture. Gray, Blue, and Green have all been used on the threatened Aleutian Canada Goose, which breed in the Aleutian Islands and migrate along the west coast as far south as California.
Three digit collars can have either the 1 vertical/2 horizontal character pattern or three digits running up the collar. Three digit flexible "bib-type" collars are used in the Atlantic Flyway. These collars sit low on the breast and include unusual characters like +, @, #, %, ?, =, etc.
4 DIGIT COLLARS
Collars with 4-digits have been manufactured in several colors, and identical codes are repeated on each collar. The codes that are used are coordinated and assigned by the Bird Banding Laboratory and are unique combinations of codes and color. Codes are in several patterns, but usually one of the following types: LNNN or NNNL (L=Letter, N=Number); or combinations of 2 letters and 2 numbers (LLNN, NNLL, LNLN, LNNL, NLNL, NLLN).
Orange and Blue collars are widely used in the Mississippi Flyway. These collars were part of an extensive effort to track the populations and movements of Canada Geese. Orange collars were used in the Canadian portion of the Mississippi Flyway, and Blue collars were used in the US portion of the Mississippi Flyway.