Moose Population Study – Yellowstone National Park

 
My wife Lisa and I initiated a 3 year non-invasive moose population study in the Northern Range of Yellowstone National Park and adjacent Custer-Gallatin National Forest in 2013. The goal of the study was to use non-invasively collected DNA to estimate population size and parameters of the northern Yellowstone moose. With advances in genetic technology, our collaborating geneticists at the University of Minnesota Duluth are able to extract DNA from epithelial cells on the surface of moose pellets (feces) and determine an individual’s genetic identity and gender. Technicians at the Smithsonian Conservation Biology Institute in Front Royal, Virginia analyze the concentration of pregnancy hormones form those pellets that we know are from female moose and can tell us if the moose is pregnant. Based on pellet volume we are also able to differentiate between 3 age classes of moose (calf, yearling and adult). We plug all this information into computerized capture/recapture models and we can generate fairly accurate estimates of population size and rates of population increase and survival.

 

Because DNA can quickly denature on the surface of moose pellets, the best time to collect them
is the winter when they are frozen and remain so until lab analysis. Lisa and I, with the help of some volunteers, constitute the field crew that systematically surveys every stream drainage in northern Yellowstone National Park that are known to hold wintering moose or winter moose habitat for pellet samples. Since we need to cover almost 1,000 miles between the two of us each winter we need to use the most efficient mode of snow travel that is permitted in the Park – Skis! For two months each winter (December 15-January 15 and the month of April) we scour drainages that contain both willow and adjacent mature conifer forest (the most important wintering habitat for northern Yellowstone moose) for fresh moose tracks. Tracks are followed until we find pellets, pellets are collected, and then we move onto the next track.

The gear we choose needs to be light but durable as we are in the field for at least 25 days of each month. We prefer Garmont Excursion boots (Now Scott Excursions), Black Diamond Traverse ski poles, Madshus Annum and Epoch skis, and Altai Hok skis. All skis are mounted with Voile 3-pin bindings. The Madshus skis are used primarily when the days are long, the snow is deep, and we are carrying heavy loads for multi-day trips. The Hoks are our secret weapon for when snow conditions are variable and some hiking is required or when the vegetation is so thick that navigating with long skis is impossible. The Hoks have been especially useful when we have conducted field work on Isle Royale, MI where much of the moose habitat is a tangle of balsam fir and white cedar……… More on our research in posts to come!