RUGER said:
Ok I am confused.
Numbers are down but pond counts are up?
What is a pond count?
PROCEDURES
Survey procedures and analytical methods for the Waterfowl Breeding Population and Habitat Survey are described in detail by Smith (1995). The U.S. Fish and Wildlife Service and the Canadian Wildlife Service in cooperation with others have conducted an annual survey of breeding waterfowl throughout central Canada, the north-central United States, and Alaska since 1955. The area comprises more than 50 strata delineated according to habitat differences and political boundaries. Since 1990 strata delineated in important duck breeding areas in eastern Canada and the northeast United States have been progressively phased into this long running wildlife survey.
Within strata, ducks are counted by two-person aerial crews while flying fixed-wing aircraft along established transect lines approximately 50 m above ground level. Transects are 400m wide and divided into segments, each roughly 29 km in length. Aerial observers do not count lone hen ducks. Ponds are counted only by the observer, not by the pilot-observer to reduce pilot workload. In prairie and parkland strata, where ground transportation networks and access is good, ground crews (initiated in 1961 for Canada and 1974 in the United States) survey a sub-sample of aerial segments. Ground counts are used to compute visibility correction factors that adjust the counts of each aerial crew for each species to account for birds not observed from the air.
Ground crews record data in a manner identical to aerial crews, except that ground crews also record lone hens of redheads (Aythya americana), scaups (Aythya marila mariloides and Aythya affinis), ring-necked ducks (Aythya collaris), and ruddy ducks (Oxyura jamaicensis jamaicensis). Since the establishment of the ground crews and unlike the aerial crew, the ground crew also counts all ponds within the entire transect width and records the side of the transect that each pond is observed on. This enables aerial pond data to be compared to the appropriate ground count when computing visibility correction factors. In boreal strata, where ground transportation is difficult, visibility correction factors are determined from a double sample of segments by helicopter. The high cost of helicopter operation currently prohibits extensive double sampling in boreal strata. The total number of birds in each stratum is estimated by the product of the density observed by the aerial crew, the visibility correction factor, and the area of the stratum.
https://migbirdapps.fws.gov/mbdc/databa ... outmas.htm
