3,800 helicopter hops?

by Jim Parker, Hamilton

Did the representatives of the Bitterroot National Forest raise any questions about the impact of helicopter flights on elk calves and their mothers?  

My first elk hunt in the upper West Fork was in 1968. I lived on Trapper Creek and hunted elk in the West Fork for 38 years.  I estimate 90 per cent of the West Fork elk herd utilizes the area under the proposed helicopter flight path for calving. Here’s what I found out about how approving the proposed “USMC Exploration” permit under a categorical exclusion will most likely impact them.

Long Term Monitoring by the Absaroka Elk Ecology Project* performed by Wyoming Cooperative Fish and Wildlife Research Unit, the Wyoming Game and Fish Department, and the U.S. Fish and Wildlife Service sheds light on the impact of large predator impacts on cow calf mortality. 

On average a response was measured when the predator breached a 1 km kilometer (approximately 3,300 ft.) safety zone. On average collared elk in the study encountered an apex predator once per week during the calving season. 

The altitude difference between where Sheep Creek enters the West fork (5600 ft,) and Conner (4,030) is just under 1600 ft In order to avoid triggering this response, the flight path of the 3800 helicopter trips proposed by USMC to transport high grade ore samples would need ascend to an altitude of 8900 ft at Sheep Creek and gradually descend to an altitude of 7300 ft at Conner before landing. 

Prohibiting / banning helicopter flights for 90 days during calving and nursing season is the 2nd option.

Quantitative Impacts of Calving-Ground Disturbance

While an isolated helicopter flight may only cause temporary flight behavior, a high frequency of overflights—such as a portion of the 2,200 flights planned by USCM over a single season—creates chronic, additive stress: [1]

1. The Disturbance Threshold: Controlled studies tracking human and motorized disruptions on elk calving grounds indicate that an average of just over 8 disturbances per cow elk results in nearly 40% fewer surviving calves. [1]

2. Cumulative Mortality Risk: Within these studies, each repeated high-level disturbance event carried an average of a 5% probability of calf death due to tracking exhaustion,

abandonment, or separation. [1]

3. Zero-Growth Ceiling: When cumulative human-induced disturbances reach an average of 10 events per cow above ambient baseline levels, monitored elk herds demonstrate no net population growth. [1]

4. Predation Vulnerability: Forcing nursing cows to abandon heavy timber security cover for open slopes leaves neonates highly exposed to apex predators.

[1]*Absaroka Elk Ecology Project:  https://wyocoopunit.org/kauffman-lab/absaroka-elk-ecology-project/