If you need further proof Colorado duck hunting is an activity governed by weather, we enter into the court record two more items of evidence.
The first is of a more conventional variety in the form of the Colorado Division of Wildlife’s annual aerial survey of the South Platte River. It suggests strongly that northeast waterfowl winged it for other parts when late-December snowstorms froze reservoirs and buried most of the food sources.
A second, more exotic, confirmation comes from a novel study by a Colorado State University graduate student to determine the effects of human disturbance on duck movements.
Josh Dooley’s preliminary findings show that this same storm caused birds that remained to radically alter patterns of movement, becoming more vulnerable to hunters.
Dooley used radio telemetry to track 88 mallards captured and collared at various locations along the South Platte corridor east of Sterling. Commissioned by DOW, the survey is intended to conclude the extent to which hunting activity disrupts birds and what might be done about it.
The researcher wasn’t prepared to learn what happened to many of these radio-equipped birds.
Hunters shot 15, including two in west Texas. Another eight died from various causes and 18 remain unaccounted for, a mystery for which Dooley offers no clues.
What he does propose is a reason for the unexpected mortality.
“They were flying more and spending additional time on the river. With food scarce, they had to move around,” said Dooley, who will present his findings at a Feb. 8 meeting of the Colorado Wildlife Commission.
Despite the fact DOW’s aerial survey counted only one-third the number of ducks as a year ago, Dooley anticipates an improvement in hunter success for a season that ends today. A final tally of hunter survey cards will determine whether he is correct.
As to the point of his research, which has another month to go, Dooley thus far has been surprised at the degree to which ducks have returned to the original scene of disturbance. He attributes this to the fact that, with all casual water and most larger reservoirs frozen, birds had little alternative but to come back to the river.
“Definitely more time on the river, lots more,” Dooley said of a situation that placed them where most hunters have access.
Meanwhile, a survey of the river corridor during the first week of January from Greeley to the state line revealed relatively low counts of ducks and geese.
Observers counted 32,000 ducks compared with 100,000 a year ago.
Geese numbers dwindled from 138,000 to 75,000, a drop that might be something of an aberration.
The lower figure actually is well within the range of annual fluctuation seen in recent years. (See accompanying table.)
But there was no such statistical precedent for the decline in ducks.
“It’s likely that storms and cold moved some ducks elsewhere,” said Jim Gammonley, DOW’s principal waterfowl biologist.
From a scientific standpoint, Gammonley issued a couple of caveats:
The count is a snapshot that doesn’t always reflect the reality of an entire season.
During this unusual weather situation, birds might be in odd places at different times and thus not counted.
Still, Gammonley concluded, “We appear to have lost some birds from northeast Colorado, but it’s unclear to where.”
DOW expects to meld all these findings to determine whether alternating hunt days on certain public areas might serve to keep birds on the Platte and adjacent sloughs, thereby boosting a lagging success rate.
But the experts might just conclude that it’s all about the weather.
Charlie Meyers can be reached at 303-954-1609 or cmeyers@denverpost.com.
