PULLMAN, Wash. – Black-tailed deer roam forested areas of western Washington and Oregon, but some say their numbers are declining. Scientists suspect that’s because these deer are having trouble finding food to eat. Researchers are studying black-tailed deer’s diet. Once they know what deer like to munch on, wildlife managers can make sure those plants keep growing in the wild.
On the hilly Palouse, four black-tailed deer graze in a shaded pen. Two scientists stand nearby. The deer are the size of large dogs. Their black tails gives them their name.
“These guys are yearlings. They were born about this time last year,” says Amy Ulappa, a Ph.D. student at Washington State University.
Ulappa has raised these deer since they looked like Bambi. She’s fed them from a bottle and knows each one’s personality.
Ever curious, the deer are alert to new sounds, new smells and new people nearby. The deer sniff and lick our microphones and cameras.
“That’s their curiosity smell. Who are you? What are you? Can I eat you? Nope,” Ulappa laughs.
Exactly what the deer choose to eat in the wild is what researchers want to find out. Scientist Lisa Shipley knows the plants they prefer: things like shrubs, grass, herbaceous knot grass.
The Washington State University researchers want to compare the deer’s food choices with what plants are actually growing in the wild.
Black-tailed deer are an important game animal for hunters. They’re also culturally significant to Northwest Indian tribes.
But new housing developments and highways have greatly impacted the deer’s habitat. Add to that: fire suppression, invasive weeds and herbicide use. That equals less food for deer to eat.
Now researchers want to find out how a forest’s age and herbicide use can change nutritional quality for deer. In a unique approach, Shipley says they’re measuring food availability from the animal’s perspective.
“I mean, Amy and I could go out and clip a bunch of vegetation, take it into the nutritional lab and find out what’s in it, but unless we know what they actually eat, we don’t know the quality,” Shipley says.
To do that, Shipley and Ulappa needed these deer to be familiar with them. That way they can stand in the middle of the herd and not be seen as a threat.
“Hi, Gale. Where you been?” Ulappa greets one yearling, patting it on the back.
She says it’s all about spending time with the animals, like bonding with good friends.
“I have a little lawn chair that I bring out put in their pen, and sit out there. They all would come around and chew on it for a bit and go do their thing,” Ulappa says.
The researchers will spend weeks camping with the deer throughout western Washington, monitoring each bite they take.
“We’ll be intimately familiar with all the plants. That’s the type of thing that we need to be able to identify plants on site. I think there are upwards of 200 species that we’re going to run across that potentially they’re going to eat,” Ulappa says.
In this acre pen, the yearlings get to munch on several different plants in a new environment. Ulappa has moved them here to so they can “practice” grazing in unfamiliar surroundings before moving on to western Washington forests. The deer have lived just up the road from this pen their entire lives.
Deer are very selective in what they eat. They sample bits of each plant and can figure out how nutritious it might be almost instantly. Shipley says they also remember what makes them sick.
“If you were a kid, and you ate Cocoa Puffs, and you got sick to your stomach, you never liked them again,” Shipley says. “And the same thing works with these animals. If they get nauseous from something they eat, they’re gonna learn really quick. But they also have some innate abilities to tell what things have high energy, high protein.”
That way they can come back to the food they like later on and eat more. Ulappa says black-tailed deer are always on a thin line of making it through the winter or starving.
“They’re kind of always living on the edge, and they need to always be optimizing their intake and expending as little energy as possible to find those food items, which we don’t really think about,” Ulappa says. “If we want a sandwich because we forgot our lunch, we can go to the grocery store. But if a deer is in a habitat where there’s nothing for them to eat, that’s a problem. And they have to move.”
Ulappa says the deer’s nutritional choices impact every other aspect of their life. That’s why she hopes studying what these deer eat will help wildlife managers to know which plants to protect.
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