The Common Ravens of Yellowstone National Park are a large, black bird of approximately 24 inches in height.  The Raven has a heavy bill and a wedge-shaped tail. They can be seen almost everywhere in the park on a year-a-round basis.
Ravens are opportunistic feeders enjoying a variety of foods, such as seasonal berries, small mammals, young birds, and amphibians. They are not above enjoying a feast on carrion.  For most of the year, ravens are more spread out across the park and primarily function as predators. If a tourist looks to the sky and sees a flock of ravens then there is a strong possibility that there is a predator kill somewhere nearby. It is not unusual to see ravens competing with bald and golden eagles when surrounding carrion.  During the summer they have adapted to human activity and will look for any opportunity to steal food off picnic tables. During the winter season, the ravens have adapted to the human activity surrounding the winter visitors, particularly those riding snowmobiles. 

When food is scarce the ravens become opportunistic scavengers Due to the limited dining facilities open during the winter,
snowmobilers will pack their lunches and snacks in backpacks strapped to back of their snowmobiles.  Whenever the snowmobilers pull over to take a short hike or go sightseeing the ravens move in to explore for food. As you can see illustrated in this photo, ravens are not easily deterred by packs that are zipped and tied to the back of the snowmobile.  They are tenacious creatures.  You can chase them away and as soon as you leave the area, they are back at work. At times it seems that they work in teams with a second raven zooming in as the first raven takes his prize off to the surrounding trees.

Heed the Warning Signs!  The national park has posted signs at every area where winter visitors may linger. The signs clearly indicate that zipped backpacks or tied packages are no match for the wise ravens.  They will not just take food, they enjoy bright and shiny objects (i.e., keys, iPods and iPhones).  They will work as a team to open any compartment in a snowmobile. 
Unfortunately, visitors seem to ignore the signs and they even laugh when other visitors warn them.  On one particularly cold snowy day in January, I chased off ravens and returned items to backpacks. I warned arriving visitors to take their lunch packs with them, with no success.  Willing or not, these visitors were enabling ravens to continue their raiding behaviors.

Ravens are very skilled at opening almost any pack!  Believe it or not, I have seen ravens unzip packs with less difficulty than most human beings. They tear open boxes of crackers or cookies, bags of chips, and zip-lock bags in search of their meals. The video below from YouTube illustrates some of the behaviors.

How many times during your travels have you seen tourists feeding wildlifeeven though signs prohibiting these behaviors are posted near-by? Perhaps even you have fed a wild animal either in your backyard, a park, or near a historic monument. In my travels I have seen people feeding wildlife of every size, shape,  and color.  Even when signs threaten fines for feeding the wildlife, some people feel it necessary to feed chipmunks, ground squirrels, prairie dogs, a variety of wild birds, and even larger animals, such as deer, elk, wild donkeys, and monkeys. 

Have you seen the signs?  Have you heeded the warnings? When I have pointed out the signs or brochures on the rules, I have heard the following reasons:
**I just wanted to get a close-up photo. 
**My children love feeding the chipmunks.         
 **The chipmunks looked too thin so they may be starving . . . I don't want them to die. 
**It is getting close to winter so I wanted the animals to fatten up in order to survive the upcoming winter weather.

** The animals are begging for food, so obviously lots of people have fed them before we started feeding them.  
**We have always fed the wildlife and never received a fine, so it must be okay.

Great excuses, but there may be some serious negative impacts that endanger the unsuspecting animal.  Allow me to cover a few of the dangers.

Human food is not healthy for wildlife! Feeding chipmunks peanuts is not a naturally occurring food for chipmunks. Surprisingly to some, store bought peanuts can be treated with chemicals that are toxic to wild animals. Definitely unsafe foods are: unripe acorns (contain excess tannin), plum stones (contain cyanide), excessive peanuts (because they can swell inside the animal).

Feeding the wildlife may create aggressive behaviors. The wild burros of Custor State Park are feral but have been habituated to accepting food from tourists.  In fact, they can be aggressive and create wildlife jams along the roads as tourists feed the animals through their car windows. Unfortunately, the burros can get hit by cars & become dangerous pests. Human food is not always nutritious or beneficial to the wild animals. Processed foods that humans eat do not offer a healthy diet for wild animals.

Just like humans who eat snack foods that are not healthy for us, so do wildlife when you provide these unhealthy options. Yes, these wild creatures may readily consume foods like popcorn and bread, but these carbohydrates do not provide sufficient nutrition while these processed food items will disrupt their digestive system. Further, as wildlife become reliant on the food provided by tourists, they stop feeding on the natural foods in their local area.  These locally found foods provide the nutrition needed for their health and continued survival. 

Contrary to popular belief Cheetos, potato chips, breath mints, and chocolate are not suitable food sources for wildlife. Fed animals may become more agressive with each other or with tourists.  If an area is a 4 season destination, then reliance on an abundant artificial food source may result in the animals not migrating during the proper time, or a failure to stock pile natural foods neccessary for survival over the harsh winter season. Further over-feeding may result in over-population of the species in an area which leads to greater incidence of diseases or insufficient local food for the population to survive when tourist numbers are low or infrequent due to the winter or low tourist season.

Over-feeding or feeding in a specific area where humans gather will change animal behaviors.  Typically, wild animals naturally disperse across the landscape, but artificial food sources promotes the
concentration of animals into a small area increases the incidence of feces, saliva, and urine, which easily harbor infectious disease-causing
micro-organisms like bacteria, viruses, or fungi.  Further if food is not consumed fully, the remaining rotting food will attract mice and insects.  This increases the potential for the spread of disease .

Feeding chipmunks at Bryce National Park and Zion National Park has increased the number of chipmunks hit by automobile traffic as they have lost the fear of humans.  The chipmunks can be agressive with humans and frighten small children.  It is not surprising to see an increase in the number of animal bites reported by unwary tourists who ignored the signs.

Please be a responsible tourist by refraining from feeding the wildlife.  Encourage other tourists to avoid feeding the wildlife.  I remember seeing a sign that read "A Fed Bear is a Dead Bear!"  Perhaps we should say a fed wild animal is a dead animal. 

As a swimmer I can relate to this illustration. . . imagine swimming laps in a 25 yard pool.   

 To imagine the 100 yard distance, consider the image of a football field. 
For those individuals that lull themselves into thinking that these animals are tame, consider the following YouTube video of a Bison attack.