units, or flyways--the Atlantic, Mississippi, Central, 

 and Pacific Flyways. This concept of waterfowl man- 

 agement has been accepted since 1948. 



A flyway is actually a vast biotic region that has 

 extensive breeding grounds and wintering areas con- 

 nected by a complicated system of migration routes. 

 These migration routes are not necessarily uniform 

 and may vary between species. The breeding grounds 

 that supply one flyway often overlap those supplying 

 another flyway; this is especially true in Canada. 

 Also, a considerable mixing of birds from two or 

 more flyways occurs on the wintering grounds, par- 

 ticularly along the Gulf of Mexico and the east coast 

 of Mexico. An important point to remember is that 

 during the fall migration period the flyway popula- 

 tions, for the most part, are distinct by the time the 

 birds produced in Canada reach the United States. 



Breeding population and production surveys are 

 conducted annually on the waterfowl breeding grounds 

 to estimate changes in the relative size of the fall 

 flight from each of the breeding areas. Two surveys 

 are required. The first is made during May and June 

 to measure the distribution and relative size of the 

 various breeding populations. The second survey 

 is carried out during July for the purpose of forecast- 

 ing the relative number of young of each species 

 produced. 



Extensive banding programs in Canada and the 

 United States clarify migration routes of these game 

 birds. Recoveries of bands from waterfowl taken 

 during the hunting season bring out facts not only 

 on the relative importance of specific waterfowl breed- 

 ing areas to the four flyways but also on hunting 

 pressures, mortality rates, and bird distributions. 

 This information guides waterfowl administrators in 

 their attempts to maintain a proper balance between 

 the waterfowl populations available to the hunters 

 and the estimated number of birds taken by the 

 hunte r s . 



Each January the Bureau conducts an aerial 

 survey throughout the United States, Mexico, and the 

 West Indies to determine the status of the continental 

 waterfowl populations after the hunting season. More 

 than 1,000 wildlife technicians from the Canadian 

 Wildlife Service, Provincial game departments, and 



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