Waterfowl Pair and Brood Surveys Buffalo Lake Moraine (1989-2003)
A. Murphy, J. Potter and R. Bjorge
The Buffalo Lake Moraine (BLM), located in the Alberta Central Parkland
Natural Region was selected by the PHJV’s Alberta Technical Committee as the first area
for implementation of the NAWMP in Alberta. In 1989, Alberta Fish and Wildlife and
the NAWMP initiated this project to monitor wetland conditions and waterfowl
populations in alternating years using a standardized protocol (Allen 1989).
In May 2003, total pond numbers were average, but an unusually high percentage of
these ponds were Class I ponds that dried up very quickly. The number of dabbling
duck pairs on the study area was less than half of the long‐term average, and the number
of diving duck pairs was very near the record low observed in 1989. These low pair
numbers were almost certainly related to lower than normal water levels in the
permanent and semi‐permanent ponds on the study area ‐ combined with unusually
good wetland conditions across most of southern Alberta (Buelna, 2003).
Duckling production in 2003 was the lowest recorded over the eight surveys. Dabbling
duck production was below average and diver production was extremely low. Diving
ducks produced only 15 broods/100 pair. When cavity‐nesting species (common
goldeneye and bufflehead) are excluded, duckling production by the remaining divers
was only 22% of the eight‐survey average.
On average, the BLM contains approximately 18,000 class III‐V wetlands and 3,200 class I
wetlands each May, and supports a spring population of almost 60,000 duck pairs (42,500
dabblers and 17,200 divers). Pair numbers are related to the abundance of Class III‐V
ponds for both dabblers (r=0.777), and for divers (r=0.766); but also reflect the size of the
continental populations, and the relative attractiveness (pond numbers) of alternate
habitat (particularly southern Alberta).
Brood production by diving ducks is related to both Class III‐V pond numbers and pair
numbers. However, the relationship between pair numbers and brood numbers may be
created by relationships between Class III‐V pond numbers and both pair numbers and
brood numbers. Dabbling duck production is more stable and resilient (30,000+ in all
years) than diving duck production (<10,000 in 2003). This probably reflects the ability of
dabbling ducks to utilize shallower ponds and to use upland cover for both nest and
brood concealment. Dabbler brood production was not related to May numbers of Class
Pair population and productivity differences between blue‐winged teal and mallard
suggest that nesting cover is still limiting mallards in the BLM.