That's so Raven

If by numbers only, Ravens dominate both the sky and land in Hoonah. So numerous are these large black birds and so connected to this area that Alaskan Natives, from time immemorial, have named one of two of their "moieties" after them.

Scavengers by nature, they are often seen picking through trash bins and garbage cans of our little village. Special care has to be taken to secure the lids. Sometimes people use logs or axes to hold the tops down. Even still, I have watched ravens knock the wood or heavy tools to the ground and then use their large beaks to pry the lids open. Once they get to the contents, others join them and the result is a mess; trash is strewn all over the ground. We have also seen eight or nine of them surround a bald eagle, never challenging him, but forcing the great bird to protect his kill while he eats. From our picture window, we have noticed pairs of ravens chasing intruders for miles and engage in aerial fighting to protect their territory.

Ravens are very vocal creatures. According to a study done by Ornithologists Boreman and Heinrich in 1999, ravens have fifteen to thirty-three categories of vocalizations; alarm calls, comfort sounds, chase calls and calls designed for claiming territories. Their voices can be heard throughout the day, from one end of Hoonah to the other: screaming, bawking, kawing, coo-cooing and warbling. There are no city sounds to compete with brash character of the raven, and the stately eagles remain refined in their contribution to the air waves.

Ravens are so much a part of our daily lives that we decided to do a science experiment on their eating patterns.

BACKGROUND INFORMATION
One morning before school Andrew put his uneaten buttered toast out in the drive way and in seconds a raven swooped down and pick up the food. Then next morning he placed and unbuttered, untoasted piece of bread outside and a raven didn’t come for about a half-an-hour. One afternoon, on the way to the park Andrew threw his apple in a snow covered field and immediately a raven flew down and carried it away.
This made Andrew wonder why they came quickly for buttered toast and apples and not for plain bread.

QUESTION
What item/food will the Ravens pick up/investigate most quickly; salami, buttered toast, plain bread, hard boiled egg in shell, apple or a plain red box?

HYPOTHESIS
Andrew predicted the Ravens will come most quickly for the salami, because they will smell it.

MATERIALS
One piece of round salami, one piece of buttered toast, once piece of plain bread, hard boiled egg in the shell, half eaten Fugi apple, and a red “Better Cheddar” cracker box*
Graph Paper, Timer , Pencil and Assistant (mom)

*We wanted to try a non-food item as a olfactory control element

PROCEDURES
For six days one piece of food/item will be placed in the driveway at different times* by the assistant. The researcher starts the timer the moment the food hits the ground and stops the timer when the Raven picks it up the food. The weather and temperature is recorded each day at the time of the experiment.

*We used different times as to not train the Ravens to come at the same time everyday.

RESULTS

Monday, 11:30 am
Light snow, 34 degrees
1 piece of Salami
Raven picked up salami in 42 seconds

Tuesday, 10:00 am
Overcast, cloudy, 34 degrees
1 piece of buttered toast
Raven picked up toast in 18 minutes

Wednesday, 12:30 pm
Light Snow, 36 degrees
1 piece of plain bread
Raven didn’t come
After 10 minutes added one piece of pepperoni and one piece of salami,
Raven didn’t come
Andrew went outside and ripped up the salami
Raven came in 5 minutes 56 seconds

Thursday, 3:00 pm
Heavy snow, 32 degrees
1 red “Better Cheddar” cracker box
Ravens didn’t come
Snow started to cover the box
After 16 minutes assistant placed a piece of salami on the box
Ravens didn’t come
We retrieved our box and untouched salami

Friday, 5:15 pm
Mainly Sunny, 37 degrees
1 hard boiled egg in shell
Before Andrew placed the egg he waved it around, tried to get Ravens attention, did a little dance in the driveway and then left it on some black rock so the birds could see it.
Ravens didn’t come
After 16 minutes Andrew brought the egg in and used red food coloring to dye it light red
Ravens didn’t come
We left egg there
An hour later a Raven swooped over, stopped on the snow five feet above the egg but didn’t pick it up
We left the egg there overnight
Around noon a Raven picked up the egg

Saturday, 6:00 pm
Unknown
1 half-eaten Fugi apple
Unknown

CONCLUSION
While common Ravens perceive their environment through vision, some chemical cues, tactile, and auditory stimuli, we could not find a pattern in how they choose their food. Perhaps the Raven had to see us place the food in the spot, or would spy it from the air come to investigate. A Raven picking up the food didn’t seem to be affected by weather, color of item, or smell of item.

They did come one time very quickly for the salami but the other days when the salami was added the results were not quick or consistent.

Andrew enjoyed seeing the birds close up and finding out the results.(Mom enjoyed seeing Andrew do a raven dance in the driveway.)

NEXT TIME
Next time Andrew wants to try the experiment for a two-week period with a greater amount and variety of food.