Hi Mitch (and all),
Thanks for sharing your perspective on this; it's something I've thought about a lot and enjoy discussing (sorry about this wall of text and if I've gone too far off-topic). I'm with you on some of the overzealous warnings against anthropomorphism. I believe that the most basic emotions are not special or uniquely human, they are primitive tools that evolved long ago, that motivate an organism to do things that are necessary for its survival. It doesn't make sense to me that humans are the only species experiencing emotion, despite many other species displaying reactions and neurological activity that parallels what happens in the human brain. They may not experience emotion in exactly the same way, but I'm convinced that at least birds and mammals have emotions (and probably fish do to some degree, according to some new research).
At the same time, our desire to interpret other species' behavior in human terms can be misguided, or even slightly disrespectful, though it isn't meant that way. If we look at emotions as tools that are refined by natural selection, then it makes sense that not all species need the range of emotions that humans have. I think of predatory animals who kill newborn animals. If they experienced empathy as you or I do, they wouldn't be able to do what they need to. Perhaps they show empathy to members of their own species, but it's important that they don't empathize with the species that they prey on. Similarly, a solitary animal doesn't experience loneliness, for good reason. There is a tendency to attribute certain emotions to animals that they actually don't need in their lives. On the other hand, domestic dogs have a very complex social structure that incorporates humans. For them, emotions such as love or loneliness are likely real and intense, because those emotions are critically important for dogs (or wolves) to bond and survive as a pack member or in a human family.
When I said that the hummingbird feels no affection for us, I was thinking about his lifestyle and which emotions would be important to him. Male hummingbirds do not form pair bonds and they don't take part in parenting, unlike most male birds. We can't really know for sure, but well-developed prosocial emotions would probably not be a useful tool for male hummingbirds. Female hummingbirds probably experience feelings of affection or attachment toward their babies, but the mother will become antagonistic to them soon after the babies are grown and fledged. So that's why I doubt that our hummingbird cares about us personally, though he probably is excited to see us when he's hungry, because he has learned that we are associated with food. This is not to diminish him in any way, just to appreciate how different his social world is from ours, and that friendship or affection isn't important to him.
I also think that to a hummingbird, claiming and guarding multiple sources of nectar is of the utmost importance. Our hummingbird sees the handheld feeder as a novel food source, and he wants to investigate it to learn more about it and remember its location. Because we carry the feeder around to various places in the yard, the hummingbird may be treating it as a new nectar source each time that it appears in a different location. I don't mean to imply that he's an unfeeling automaton, but to try to understand his point of view and how he experiences the world. I want to avoid anthropomorphism where I think it would be in error, but I also believe that hummingbirds experience some other basic emotions. The hummingbird just has no need to feel affection, and he may not even have that ability. He has so many other wonderful abilities, I don't care at all if friendship or affection is meaningless to him.
Speaking of birds with a broad spectrum of social emotions, I have had numerous California Scrub-Jay and American Crow friends over the years, and I thought that even though they came to me primarily for peanuts, our relationships were a little deeper than that. I think hardly anyone doubts that they are very intelligent birds, after the last few decades of research. Corvids, especially crows and ravens, require a range of emotional tools to navigate their complex social structure, many of which are likely shared by dogs or even humans. I knew some of the jays really well, Mr. Pill, Peanut Queen and Mr. Shy were all wonderful birds with distinct personalities, and I cared about them a lot. They appeared to enjoy my company as well, though I'll never know how they experienced our relationships. It's reasonable to say that a crow can feel lonely, or that it has close friendships, because I think those emotions are vital for crows -- but not for all species.
I am hopeful that, as science continues to collect evidence of emotions in other animals, humans will feel more compelled to improve the ways we treat them.
Today, I was holding the feeder and watching "our" hummingbird chasing a couple of other hummingbirds out of his domain. He veered away after seeing them off and flew across the yard toward me, just a bright magenta spot coming closer until he alighted on my finger to drink nectar. It is a privilege to have a wild bird land on you, and I hope some people give this a try (also try holding sunflower seeds for Pine Siskins).