A couple of weeks ago I was headed down to Totem Park and noticed the high frequency down slurring call of an American Robin’s aerial predator alarm. After watching a robin nest in my yard get cleaned out by a raven last year, and coming to realize a little better the true significance of this call for the robins, I’ve come to pay more attention to it. On this particular day, I first noticed it in the distance while walking down Etolin Street, but after rounding the corner and going down Jeff Davis I was a little surprised to find that it was coming from a tree across from campus drive. I was able to see the alarming robin perched fairly high up in the tree and appearing to face south.
I looked around for raptors and ravens, but didn’t see anything in the immediate vicinity. The robin continued to call, and I was able to get recordings of it (including the one above), but still couldn’t figure out what it was concerned about. After a couple of minutes, I happened to notice a raven flying across to the south of me and the robin. I had not noticed it previously, and so do not know where it might have been perched prior to the flyby. I think it probably wasn’t too close, or i would have noticed it, I’m guessing it was perched somewhere in the area, since after the raven flew out of site, the robin promptly stopped making the alarm calls. It clucked a couple of times, then it when about its business and I continued on to the park.
Fast forward to a bit over a week and once again while walking down Jeff Davis, I heard a robin alarming (this time a little further up the hill). I had already noticed a raven in some tall hemlocks, and when I finally found the robin in a cherry tree, it was facing in the direction of that raven. I took the picture above instead of trying to make a recording, and seeing its beak full of worms, I’m fairly confident this robin was carrying food for a nestling, but alarming while waiting for that raven to tire of sitting there. I didn’t have a whole lot of time, so I did not see how long the waiting game took this time.
As yet unanswered questions I now realize I have:
- How far away do ravens need to be to not be alarmed at?
- How good is raven eyesight? You hear about the eyesight of hawks and eagles, but maybe the ravens are pretty good at seeing also?
- How long do ravens typically wait?
- Why don’t ravens wait longer? It seems like in this particular game, the raven can afford to wait longer than the robin.
Thoughts on these questions, or more of your own? Please feel free to leave a comment.