^^^ Migratory bird populations 



Management and conservation of migratory 

 birds, including waterfowl, mourning doves, rails, 

 snipe, woodcock, and many song birds, are the 

 responsibility of the Bureau of Sport Fisheries 

 and Wildlife under Migratory Bird Treaties be- 

 tween the United States and Canada and Mexico. 

 Patuxent biologists and statisticians help the Bu- 

 reau to meet this responsibility, primarily by 

 developing techniques of measuring production 

 and status of populations, and by supplying facts 

 on migration, distribution, and biology of the 

 various species. 



They appraise the effects of Federal hunting 

 regulations on the number of waterfowl shot each 

 year in the United States. They make these ap- 

 praisals in part by a statistically planned survey 

 of hunters. In 1957, the survey showed that 17 

 million ducks, geese, and coots were bagged. They 

 also estimate the waterfowl kill in a particular 

 State when the State wishes the information and 

 shares the expense of obtaining it. 



Files of the Center's Bird Banding Office hold 

 records of all birds banded in the United States 

 and Canada since cooperative banding began in 

 the 1920's. Records are coded on punch cards. 

 By machine tabulation of these cards biologists 

 can learn just where and when birds were banded 

 and where and when they were captured or shot. 



They use these records in many ways, but espe- 

 cially to evaluate mortality — how much and where 

 and when it occurs in different parts of the 

 Americas. From this information, they pinpoint 

 problem areas and make management recom- 

 mendations. 



Tliey are experimenting with methods for using 

 wings sent in by hunters to measure success of the 

 waterfowl breeding season. They have developed 

 good visual methods for "aging" snow, blue, and 

 white-fronted geese for use in aerial surveys of 

 wintering populations. Estimates of the breeding 

 success can be made from these data, and such 

 estimates guide the Bureau in setting bag limits 

 and length of hunting .season. 



In many States mourning doves, woodcock, and 

 snipe are popular gamebirds. Biologists at 

 Patuxent and in the States are working together 

 to learn more of the migration, biology, and 

 habits of these birds as a basis for better 

 hunting regulations. They are testing improved 

 methods of estimating woodcock and dove num- 

 bers during the breeding season; they are col- 

 laborating in research to find suitable sampling 

 methods of measuring the annual take of doves 

 by hunters; and they are cooperating in winter 

 counts of snipe to provide the Bureau with cur- 

 rent information on the status of that species. 



Tabulating machines and skilled 

 operators summarize distribution 

 of waterfowl mortality in the 

 United States and Canada. 



592757 0-61-2 



