So the wife & I were on the deck watching critters of which were birds.
Started talking birds.
That falcon shot of the falcon going through the trees, etc…
Then small bird instinct.
Question:
How big a piece of the brain of a bird is needed to store all the instinctual things a particular bird type may need?
Actual actual physical size? 1/16 inch square, or 1/32 inch square?
Or as a percentage? 10%, 2%?
For smart birds like a raven, parrot?
For dumb birds like a titmouse or chickadee?
If it is in the DNA, bound to be IMO, does it actually have to be in the brain or could it be elsewhere or even spread out in several places?
My Google Fu is asking the wrong question it seems.
Inasmuch as your question is meaningful, nobody knows the answer to it. Brains don’t really work that way. There are not some parts devoted to instincts and some devoted to other stuff. (Also, although the surface layers of the cerebral cortex are of particular importance in higher animals, especially humans, brains are three-dimensional objects and the inside parts do do vital stuff, so you shouldn’t really be asking about square inches.)
Looking at your question from another perspective, in order to be able to do all the things it does, an animal needs precisely all the brain it has (and no more). If you are trying to draw some distinction between “instinctual” things an animal does and other things it does, you would need to make it clearer where you think the division lies. Your question would still not have an answer, however.
Well it is in their brain somewhere, no doubt, but that doesn’t mean that it is in a particular region of their brain. A function like that might only involve a few neurons, but they do not necessarily have to be close to one another within the brain. Even in a human brain, some neuronal axons can stretch pretty much right across the brain to the other side, so that widely separated neurons can sometimes be working together. In an insect brain, one side to the other is hardly any distance for an axon to reach.
No, its not unknown, and in a mammalian brain, and especially a human one, most of the action is generally in the surface regions (the cortex) anyway, although stuff deeper in is still doing important work. Actually, a lot (though by no means all) of the interior is “white matter” which is essentially connections (cables if you like) between different regions of “grey matter” (where the actual neuron cell bodies are) in the cortex and elsewhere.
The main point, though, is that the pictures that you see of brain regions do show you where things like instincts (or memories, or particular sorts of knowledge) are; at best, the pictures you see of brain regions are showing you where various functions are (mainly) carried out: that is, some regions are particularly involved with visual processing (and even particular aspects of it, such as motion detection or color vision), others are concerned with hearing, others with controlling the muscles of various parts of the body, etc. “Instincts” are a different sort of category, that is not really relevant to questions about brain regions. As Gilbert Ryle put it, it is a bit like like if, after having been shown round Oxford, and seeing all the colleges, you were to ask “But where is the university? Why haven’t you shown me that?” (Also, a lot of the reporting in the press, in the last few years, about brain imaging and what it reveals about which bit of the brain does what, needs to be taken with large pinches of salt. The reliability and meaningfulness of the results from brain imaging - which is far from the only technique for investigating brain function - have been seriously oversold.)
The page at the link below does a good job of comparing the avian brain to the human brain and I believe answers your question in a way that makes sense both in the way you asked it and in the modern understanding of brain function.
Scroll down to the pictures showing the “Classic View” and “Modern View” of the compared brain anatomy and you’ll see they specifically address the issues of “instinctive” vs. “complex” in terms of brain anatomy and relative sizes of brain parts dedicated to those sorts of functions.
Well, yes, but although that article’s diagram of “the classic view” does show some brain areas as devoted to instinct, the point of contrasting that with “the modern view”, as the article does, is that “the classic view” is no longer considered to be correct. It is, essentially, obsolete, refuted science. The modern view does not assign particular areas to instinctive behavior.
It is true that some brain areas, notably the brain stem (in humans, and no doubt in birds too) are responsible for some very basic, life-maintaining functions, such as temperature regulation, keeping you breathing, and keeping your heart beating, and they will continue to do this even if the cerebral cortex is rendered non-functional. Some of those functions, notably breathing, might be considered to be instinctual behaviors. However, there are many other instinctual behaviors, such as (in birds) nest building, singing, territoriality, mating rituals, etc., that most certainly rely heavily on other areas of the brain, indeed, on much if not all of the brain, including the cortex. I take it that it was these these more complex instinctual behaviors that the OP was primarily asking about, not about stuff like breathing and heartbeats.
To extend on this, it is charitable at best to say that most arthropod, nematode, flatworm, and nemertea species, even have a brain, insofar as the brain is a cluster or ring of a handful of simple undifferentiated ganglia that has little malleability after morphogenesis.
“Instinct”, insofar as it can be distinguished at all from cognitive action, is largely an artifact of the neural pathways. While these are in large measure determined by the physical construction of the nervous system as dictated by genetic and epigenetic factors, many of the things we commonly think of as being “instinctual” are formed after primary ontogeny. For instance, the aversion to touching a “red hot” item on the stove is not instinct; although the pain response from high heat is an innate response, the association of near-infrared radiation from hot items is clearly a learned response. Nonetheless, once it has been learned (usually by direct experience) the response to pull away is essentially involuntary insofar as it does not require any higher cognition (e.g. a measured response) and is ingrained in the constantly developing neural pathways.
Fundamentally, a bird or other animal needs all of the brain it has to do the things it does. How you break this up into “instinctual” or “non-instinctual” is a fairly arbitrary distinction.
The instinct I am referring to is not auto heart work, digestive system operation, etc., but those things that have never been seen or trained for but that the creature still knows how to do just as well ( or almost as well ) as one with experience.
Where does that information come from? Is this the right question?
As I think I already said, if (or inasmuch as) a behavior is truly instinctual, rather than learned, it is encoded into the structure of the nervous system, mainly the brain, and comes from the anima’ls genetic endowment, which got that way thanks to evolution (I suspect you knew all that, though). What we can’t say, meaningfully, is where in the brain that is, partly because we don’t know enough about brains yet, but mainly because it is just not a very meaningful question: the control of most complex behaviors requires all, or at least most of, the brain, although different types of behavior (whether instinctive or not) will use different parts of the brain to different degrees and in different ways.
For instance, one might find (indeed, for all I know people may already have found) areas in a bird’s brain that work particularly hard when it is singing its song (bird songs are at least partly instinctual, although I think the degree to which they are varies from species to species), but it does not follow that all the information behind the song instinct is encoded in that brain region (or, indeed, that that region is doing all the neural work necessary to produce the song), and, in any case, quite different regions will probably be working hardest during the performance of other instinctual behaviors, such as nest building. You can’t say, as your OP seemed to want, “This bit of the brain is devoted to instincts, and these other bits are devoted to other stuff, such as learned behavior.”
Well yes, brains (even bird brains) are very complex and there is a lot we don’t know about them, but I think we do enough to say that there really is not ever going to be a meaningful answer to your original question. Brains are just not divided up along the sorts of lies you were envisaging.
This isn’t really an answer to the OP, but it’s a hint that they are starting to figure some of this stuff out:
“Studies in barn
owls have revealed that the additional learned circuits
that had been assembled during a sensitive period in
juvenile birds were turned on and off in the adult through
mechanisms distinct from those that turn innate natural
circuits on and off (disinhibition versus AMPA/NMDA
ratios for the innate and learned circuits, respectively), suggesting that innate and acquired circuit arrangements
can be distinguished functionally64,65”
This is from an article with this title: Structural plasticity upon learning: regulation and functions
I tried to add a link but the URL pointed to my downloaded copy and the other link required some sort of membership.
But distinguishing a circuit isn’t the same as having separate neurons for just these functions, neurons can be part of multiple circuits.
