
217 
WATERFOWL BREEDING GROUND SURVEY - IOWA, 1955 
James G, Sieh 
Introduction 
Breeding pair and brood studies have been carried on during routine 
on-the-spot check counts in the prairie marsh areas of northwestern Iowa since 
1949 to evaluate the trend of nesting waterfowl other than wood ducks. Wood 
duck stream surveys were begun in 1953 and repeated in 1954 and 1955 in an 
attempt to determine wood duck production trends (Table [). Wood duck nesting 
box checks have been completed on the Lake Odessa area in Louisa County to 
determine nesting box utilization and to evaluate production each year since 1950 
{Table II). Random nesting box checks have been made intermittently in north- 
west lowa since 1949. 
Aerial survey of the prairie marshes has continued in northwest Iowa 
using a lineal census technique which was modified in 1953 and 1954 to attempt 
total counts on individual lakes, sloughs, and marshes. 
Spring Migration 
Following a mild winter early migrants were moving into and through 
Iowa during the second week in March. Scaup and ring-necked duck were numer- 
ous inearly April. A large migratory build-up of blue-winged teal developed 
during the third week in April, while laggard blue-wings, scaup, and shovelers 
remained in northwestern Iowa during early May. A warm spring hastened 
migration into and through this State. 
Waterfowl Production 
On-the-spot check counts in the prairie marshes of northwest lowa 
each spring and summer since 1949, plus aerial coverage of the same marsh 
units since 1952, have provided a studied opinion as to the production trends of 
blue-winged teal and mallards, Blue-winged teal constitute the most numerous 
nesting species in the remaining prairie marshes, and the mallard is not far 
behind, Production of these two species in 1955 exceeded production during 1952, 
1953, or 1954, With the exception of increased production in 1951 which 
resulted from optimum water levels, excellent nesting and survival conditions, 
the production trend of ground nesting species, especially blue-wings, and 
mallards, tend to remain about the same under average phenological conditions. 
During the last six years of systematic observation, 1951 marks the only year 
when a large increase of breeding stock occupied the many temporary potholes 
and nested successfully, 
