A digression, not a bird; click for incongruity.
I still see no reason to presume life hasn't had time enough for certain aspects to evolve as they have. I admit I suddenly find myself fascinated at the question of what happens if we disrupt magnetic fields around the organism
in ovo, and how that relates, when magnetoreception is involved, to the question of returning to a particular nesting ground or other such behavior.
The
Cornell Lab of Ornithology↱ explains:
The mechanisms initiating migratory behavior vary and are not always completely understood. Migration can be triggered by a combination of changes in day length, lower temperatures, changes in food supplies, and genetic predisposition.
To me, "hard-wired in the brain" is a genetic predisposition. This is within the range of our comprehension, generally speaking, even if there is still much we do not know. Quasi-lamarckian survival-defense adaptation heritability suggests there is some manner of generational teaching, depending on how we define "teaching". Epigenetics appear to contribute to certain stimulus-response data coding into the system in such a manner that is apparently heritable; this is demonstrated in lab rats, using something that smelled like cherry blossoms, as I recall. (And damned if I can find any of my own posted references that would list the source article. [
sigh])
Basic stimulus-response is pretty straightforward. The scent can be quantified; therefore,
if [scent]
then fear. What I'm less certain about is what would qualify, and not everything will work quite the same way, or else it does, because doesn't it all come down to proteins?
Eat this instead of that; the next generation might inherently recognize the potential not because it "learned" anything, but simply because it developed (gestated) in an environment including certain protiens produced in epigenetic processes reflecting (responding to) the dietary change. And maybe those lines prosper in the evolutionary parade because they were a step ahead when the original food source collapsed and the larger portion of the population began its adaptation later and under more strained circumstances.
But this thing with
fear. What is it, then, if an organism has no word for fear, nor capacity for words. Drosphilia respond to changes in air pressure; they do not do so for a lark.
Migratory or other conditional behavior might be survival-oriented, but this notion of fear does not quite work if the organism is simply inclined to follow warmth; there is little benefit, for our context, in psychoanalyzing affirmative behavior as responsorial―the organism is following warmth, not fearing a lack thereof.
Long-range magnetically mapped migration in birds is an impressive feat, but the more instinctive behavior, quite honestly, does not seem so mysterious; it's just that we might tremble at enumerating the criteria as if in a database, though that's almost how my speculation imagines it. Essentially, it's a massive complex of if/then routines that only have consequence when enough criteria are met that the if is satisfied and demands a then. And, yes, life has certainly had enough time, as I see it, to refine a great deal of this.
Humans can walk, chew gum, talk into bluetooth while checking mail on our mobiles in between building massive networks, hurling robots out into the Universe with thrilling local precision, and have learning how to harness fusion power akin to the sun, that we might destroy most of the living endeavor.
That nature has figured out how to build animals that aren't utterly hopeless from the moment of their accursed birth is not so much unsurprising as rather quite expected. How big of a leap is it from eating because one is hungry to moving in this direction because some impulse says that's what you do? And eating because one is hungry is probably unfairly complex; the basic demand is to consume, and everything else is circumstantially responsive.
At a cellular level, a bird is made up of a bazillion tiny machines designed to particular purposes, the sum effect of which is a bird. Evolutionarily speaking, the tiny machines whose operation results in immediate migratory impulse are
dazzlingly specialized.
And from there it's if/then. Once enough criteria are fulfilled, and enough impulse signal generated, the bird does what it does. I do not perceive the necessity of transmitting, receiving, learning, and calculating data from one generation to the next in such communicative fashion. And to that end, hard-wired is a fine description: It isn't a matter of programming language, but the shape of the circuits the software acts on.
Perhaps part of my problem in this is persistently trying to imagine the
somehow in teaching each generation anew. Yes, it seems sarcastic to say something about show me the mommy bird teaching baby bird this, that, and the other, but perhaps it sets us up well enough to suggest that while bird language is far more subtle than we have previously imagined, I'm pretty sure she's not encoding actual complex math in all that. To some degree you can use your own experience. Nobody taught me explicitly how to do silly stuff under the water, and if you've ever, say, been pulled around by a foresail lost to flutter, there is a moment when you're trying to haul it back in and you can keep yourself on the deck but suddenly from your brain to your arm to the sheet to that massive sail full of
so damn much air, and you've got a really taste of it because you can feel the shape of the air through the sheet as if it all really is an extension of the body—it's the damnedest thing, I tells ya, but it probably helps that every alarm in your reflex is clanging loudly at that point because, honestly, the stays really hurt to crash into, and if not you're landing in the drink, so everything comes down to staying on the deck and in later years you will, so long as you survive the day, find a moment to ask your father why actual lifelines weren't a priority back then. Hang gliders? I don't know; I haven't the courage, but I suppose that or a freakin' squirrel suit are about the only way to actually get the feel.
And all that to suggest that to some degree, for the bird, once those wings catch air, the rest is natural. Every cell in its central nervous system is attuned to this. And, you know, eff all, you'd think an albatross would learn how to land properly. But it's also true, when you fly seven thousand miles a stretch ... no, honestly, it just cracks me up beyond belief, akin to the God/Darwin f/u bit Robin Williams laughed about once upon a time, only more so.
It's true a bird can learn to maneuver just like so by watching others, but they're not transmitting the mathematical formulae any more than my father taught me the numbers for water skiing. I mean, sure, you can instruct someone in getting up atop the water, but carving is virtually all feel, and imitation helps.
Or, rather, I digress. But I do think we should be able to see evidence of some larger epigenetic operational structure if we expect active data transfer. It's a lot of information, and considerably more complex than, say, olfactory memory or flight response memory. And compared to the prospect of specialized cells making a specialized organism that behaves in a specialized manner, that active generational transfer seems extraneous, and I'm not even certain how to begin describing the question of accounting for signal transmission quality in somehow being taught anew each generation.
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Notes:
Cornell Lab or Ornithology. "The Basics of Bird Migration: How, Why, and Where". 1 January 2007. AllAboutBirds.org. 14 March 2017. http://bit.ly/2mqumvP
