benefiel@wyse.wyse.com (Daniel Benefiel xtmp x2531 dept234) (06/28/91)
I've been noticing a certain behavior in the hummers at my feeder, and it reminded me of past discussions such as "Why Doves & Pigeons bob their heads when they walk" and "Why Robins tilt their heads when worming." When I'm close to the feeder, the hummingbirds sometimes prefer to keep an eye on me, and so they sit on the opposite perch facing me. Then, they feed by taking a sip, raising their head, and looking at me, first with one eye and then the other. It seems they can't see me by looking straight on, and that it helps to use both eyes, even if not at the same time. But, if they can't see straight on, how do they get their beaks in the feeder, or, better yet, catch insects?
rsl@cbnewsm.att.com (randolph.little) (06/29/91)
In article <3209@wyse.wyse.com>, benefiel@wyse.wyse.com (Daniel Benefiel xtmp x2531 dept234) writes: > > I've been noticing a certain behavior in the hummers at my feeder, and > it reminded me of past discussions such as "Why Doves & Pigeons bob their > heads when they walk" and "Why Robins tilt their heads when worming." > > When I'm close to the feeder, the hummingbirds sometimes prefer to > keep an eye on me, and so they sit on the opposite perch facing me. > Then, they feed by taking a sip, raising their head, and looking at me, > first with one eye and then the other. It seems they can't see me > by looking straight on, and that it helps to use both eyes, even if not > at the same time. But, if they can't see straight on, how do they get > their beaks in the feeder, or, better yet, catch insects? Indirect evidence that hummers can see straight ahead is that they have managed to survive generations of flight at breakneck speeds through tight quarters without needing to waggle their heads. So let's assume they can see perfectly well "straight on" and consider why they might keep just one eye on you. First, consider that you are perceived as a threat, or at least a suspicious object worth watching. Second, consider the selective consequences of focusing ALL attention on the first suspi- cious object. Third, consider that anxiety is increased by the detection of your presence. Put this all together and conclude that head motion is stimulated by your presence, to be on the alert for other dangers from other directions, but all the while keeping at least one eye on the recognized danger. (Hypothesis offered without proof.) -- Randy Randolph.Little@att.com