pond levels. July pond estimates indicated an overall de- 
crease of 58% from those of May; stratum 39 suffered the 
greatest loss (67%). Results still compared favorably with 
those of 1978 (6% increase) and were only 6% below the 
10-year mean. Additional water losses, however, occurred 
at a rapid rate through the survey period and afterward, 
and no doubt the situation was worse than the figures 
showed. 
Production (Table B-6) 
The duck brood index dropped considerably from that 
of 1978 (—37%) but remained above the 10-year mean. 
The mean brood size of 5.2 compared favorably with that 
of 1978 (+5%) and was essentially unchanged from the 
mean (—4%). The coot brood indices showed an insignifi- 
cant 4% decline from both 1978 and mean figures. 
In spite of the crew's optimism in May, a predominance 
of Class I broods in the sample strongly indicated a poor 
early hatch and brood survival. The unusually cold and 
wet spring could have caused any or all of the following 
problems, which in turn could account for this observed 
result: reduced hatchability of eggs resulting from cooling 
or freezing; increased mortality rates of newly hatched 
ducklings due to exposure; a change in normal breeding 
behavior due to environmental stress; and stress-induced 
changes in predator behavior. In addition, the rapid and 
nearly complete disappearance of water in areas where 
shallow water was abundant in late May may have had a 
disastrous effect on early broods. Although there are 
countless variables in any year which can affect waterfowl 
production, it seems logical to assume that the extreme 
weather conditions had a strong negative effect on early 
broods. 
The LNI provides a rough measure of broods yet to 
come. The total LNI of 50,700 represented increases of 
18% from that of 1978 and 57% from the 1969-78 mean. 
This is consistent with the apparently poor early hatch and 
the relatively large number of young broods observed in 
July. 
Individually, the mallard LNI remained virtually un- 
changed from 1978 and was 25% above the mean, Gad- 
wall and American wigeon indices increased considerably 
during both time frames, but those of green-winged teal 
and pintail decreased significantly from 1978, The total 
dabbling duck LNI increased 5% from 1978 and 50% 
from the mean. All diving duck species showed increases 
from both references; scaup was numerically most impor- 
tant. The LNI for total divers was up 82% from 1978 and 
163% from the 10-year mean. 
Montana 
Data supplied by James F’. Voelzer and John Tautin 
U.S. Fish and Wildlife Service 
Spring Weather and Habitat Conditions 
Three factors— above normal precipitation, below nor- 
11 
mal temperatures, and abundant residual nesting cover — 
combined to provide prime breeding habitat over the en- 
tire survey area. Because of the wet spring, farmers were 
unable to work their fields in the northwest quadrant of 
the survey area, and as a result numerous stubble fields 
with leftover grain served as a generous attraction for a 
record number of waterfowl. Our prime concern was that 
continued low temperatures might retard the development 
of adequate brood cover. 
Breeding Populations (Table B-7) 
Indices for blue-winged teal, northern shoveler, pintail, 
and scaup indicated the highest breeding population for 
those species in Montana since surveys were initiated in 
1965, Statistics for these and other important species com- 
pared with 1978 and the 1969-78 mean, respectively, are 
as follows: Mallard, +38% and +1%; gadwall, — 28% 
and +61%; American wigeon, -4% and -11%; green- 
winged teal, +120% and +65%; blue-winged teal, 
+199% and +98%; northern shoveler, +57% and 
+ 224%; pintail, +45% and +115%; redhead, + 110% 
and + 456%; canvasback, + 64% and + 74%; and scaup, 
+83% and +163%. Total ducks increased 45% over 
1978 and 66% from the mean. 
The 1979 lone drake index of 77.4 (mallards 76.7 and 
pintail 78.3) indicated a nesting season slightly more ad- 
vanced than normal, 
The Canada goose index should be considered as a trend 
figure only. More intensive and timely goose surveys were 
conducted by the Montana Department of Fish and Game 
and by the Service’s Division of Wildlife Refuges. 
Summer Weather and Habitat Conditions 
During the May 1979 survey, nesting habitat, although 
delayed somewhat by a late spring, reflected abundant 
residual nesting cover and excellent water quality. Total 
water areas had increased 67% compared with May 1978 
and were 38% above the 10-year mean. New growth was 
retarded but the July survey indicated sufficient brood 
cover was available. Habitat conditions, however, deterio- 
rated markedly since May. Growth of upland cover and 
cereal grains was very sparse. Crop yields were antici- 
pated to be 7% below 1978. Water areas were equal in 
number to those encountered in July 1978, 19% above the 
10-year mean, but 35% below the May 1979 survey. Lack 
of rainfall since May was the main reason for the decline 
of water areas, and an unseasonably cool spring and gen- 
erally poor growing conditions was responsible for the 
poor growth of upland cover. 
Production (Table B-7) 
The 1979 brood index of 104,300 was the largest such 
index for Montana since production surveys were initiated 
in 1966. It was 44% above the 1978 index and 115% 
above the 10-year mean. The mean brood size of 5.3 was 
3% above 1978 and 2% above the 10-year mean. 
