Last week I wrote about the hummingbirds I’d seen over my holiday break in Arizona, and I talked briefly about their behavior at the feeders – how a single hummingbird would claim a feeder as its own and guard it, chasing away any others that approached. When I unearthed my field notebooks from college, one of the things I found was pages of data on this very subject. On a trip to Costa Rica for our tropical biology class, my friend Meredith and I did a little study of how different hummingbird species interacted at the feeders at our hotel in the cloud forest.
Let me explain what’s going on in these columns of cryptic notes. The strings of capital letters were our codes for the different hummingbird species – not proper banding codes, just our own abbreviations. For example, “M” is a Magnificent Hummingbird, “FMG” is a female White-throated Mountain-gem, and “VE” is a Green Violet-ear. (Only in some species could we easily tell the sexes apart.) “Back” is just my note that I was watching the back feeder, not the front one. When there was already one hummingbird at the feeder and another one approached, we would record what sort of interaction they had. Was there no reaction, did the new one displace the one that was already there, did the one that was already there chase the new one away? As you can see, there was a lot of action. When we got home we entered all of this into spreadsheets, ran some statistics, and eventually presented the results as a poster at an ornithological conference. (Don’t ask me what the results were, exactly, because this was four years ago and I don’t really remember.)
By the time this post is published on Wednesday I’ll be on a field trip with my graduate program to Wolf Ridge Environmental Learning Center in Findland, Minnesota. Look for a post Friday or Saturday on my expedition to the northern (!) shore of Lake Superior!