Bay Nature magazineFall 2005


Finding the Stash

October 1, 2007

From the snowdrifts of Siberia to the labs of UC Davis, assistant research professor Vladimir Pravosudov has studied the food-caching behavior of various birds, including Russian birds that cache up to half a million items in one year. Born in Leningrad (now St. Petersburg), Pravosudov says his childhood interest in birds carried him from northwestern Russia to Siberia to the United States, where he became a graduate student at Ohio State University. After subsequent work at Purdue University and UC Davis, Pravosudov recently accepted a position with the University of Nevada-Reno’s biology department to continue his studies of spatial memory and food-caching behavior. Pravosudov met with Bay Nature to explain food caching by birds and his long-lived passion for his subjects.

BN: What led you to start researching food caching behavior?

VP: I was interested because I saw these small birds [in Kandalaksha, Russia]—chickadees and tits—and I was amazed at how they can survive in very long winters when they had just a few hours of light and temperatures are very low. Basically, I was doing the natural history of these birds. Which included looking at how much food they cache and when.

BN: How do Bay Area species like scrub-jays fit into the bird intelligence picture?

VP: First of all, the main premise for me was not just intelligence: it was survival skills like memory, which of course brings up intelligence. Scrub-jays in particular have been considered not to be that good at food caching because they live in mild climates, like here in Davis, in the Central Valley [where there’s less of a need to store large quantities of food in anticipation of a long, cold winter]. So, traditionally people thought that scrub-jays didn’t have very good memories. There was a lot of research trying to prove that scrub-jays do not have a very good memory compared to Clark’s nutcracker, for example. But what is interesting is that scrub-jays don’t cache intensely once a year; rather, they cache every day throughout the year. They also cache different kinds of foods; they cache acorns, yes, but they also cache insects, lizards, all different types of food. Potentially, this is very interesting because you’re caching perishable and nonperishable [food items] all over the place, overlapping in different areas, and some will last longer and some not. So scrub-jays have to actually remember not only where they’ve cached but what they’ve cached and when they’ve cached it. They keep track of time and content. Because if you cache an insect it will spoil within two or three days, while an acorn can last for a few weeks. If you don’t remember, it’s going to be a waste of energy; if you’re there two days late, it’s useless.

BN: Is food caching a good indicator of “animal intelligence”?

VP: Caching itself, probably not; I wouldn’t say so because there could be different ways of retrieving caches. For example, there are birds that larder-hoard—that is, they put all their caches in the same spot. Like acorn woodpeckers. They don’t really need to use memory for that. I wouldn’t say that they are not intelligent, but food caching would not lead to high intelligence in this particular species because all they need to do is protect [their cache]. They cache all their acorns in one tree—called a granary—and then they protect it from all their competitors.

BN: Do you worry about anthropomorphizing the animals you work with?

VP: I’m not too worried about it. I think this whole [food caching] mechanism has evolved to increase survivorship of these animals. It’s not just because they’re cute, or that they can think. It’s very simple. They cache to survive the winter. For evolution, for selection, it doesn’t matter if it’s memory or not; it’s whatever will work. If the bird survives, that’s all that matters. How it survives, selection doesn’t care, evolution doesn’t care. I’m not trying to insert human thinking into that.

BN: Does your work with birds in the lab give you insight into the birds you see outdoors?

VP: Oh yeah, my roots are in the natural history of birds. I have been interested in birds since I was seven or ten years old. I have a lot of experience just watching them in the field. So I’m trying to link this kind of memory research and neurobiological research back into the natural history of this organism and see how it all fits and how it makes sense for them. So now when I go out in the wild and I look at them, it gives me a more complete sense of how they exist and feed in this environment, and how they interact, and all of these pieces of the puzzle.

BN: Is there anything in your research that has particularly surprised you?

VP: Everything surprises me; I mean, that’s why I’m in biology. Biology is a discovery. You find something and it’s amazing.

About the Author

Matthew Bettelheim is a freelance writer and a wildlife biologist with URS Corporation.

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