In my opinion, animal behavior as asked in the question below relates closely to identification and other fauna questions addressed in these other Metas. However given the disagreement (multiple close and reopen votes) we should hash out how we want to handle this specifically .
In my opinion trying to decipher animal noises to human feelings, words, or emotions is off-topic, speculative, and subjective. I personally feel that animals can feel and express emotions but interpreting these emotions isn't something we should be doing here.
I don't really want to field questions in the form of:
How do I tell if a bear's roar is saying "you look like food" or "I'm grumpy because a stick was poking me all night" or "are you a strong enough to be my man"?
What emotion is the squirrel in my tree expressing when it makes a "chuck-chuck-eeeeoooWW!" sound?
Sometimes the quail in my yard makes a "coo-COOoo" sound and sometimes it makes a "wee-NICK-nick-nick" sound. What feeling motivates the different sounds?
The crow that built a nest outside my window makes a weird noise. Does this mean it is mentally unstable?
If a person has a recording of an animal sound and can get that into their question in a reasonable manner I think identifying the animal that is making that sound should be on topic. Identifying an animal is a completely different problem than anthropomorphizing animals and deciphering their thoughts and speech.
When Are the seagulls begging or contentedly sighing was posted, I took a long, close look. Because I was one of the most vocal proponents of bringing bird and backyard animal behavior questions to the site, I wanted to make sure to be objective. After much thinking and research, I decided that it was more on topic than I'd originally thought. An edit to make it less subjective and more clear may have made it a better example of how to use the site for birding purposes, but it's a valid example of what we should be allowed to ask.
My basic reasons:
Birding is a common fun outdoor activity, and according to our tour, we are a site
for people who love outdoor activities, excursions, and outdoorsmanship.
Should birding be on topic?, was largely answered in the affirmative
A couple of topics that are potentially quite large but are in need of some love...
In Area 51, example questions from bird and backyard site proposals were considered on-topic here, and their followers were encouraged to join us
Conversations took place in chat about helping the site grow through encouraging bird-related questions
Tags were specifically created to make it easier for birders to post their questions
Bird-related questions have received good attention from the community
The title of this post is about animal behavior, but the body appears to be based on that particular question about bird sounds and their meanings, so I'll base most of my response on that. (A response to the part about squirrel language can be found here.)
With birds, language is key to identification and understanding of behavior. By definition, birdwatching and birding rely on a language component.
Birdwatching, or birding, is a form of wildlife observation in which the observation of birds is a recreational activity. It can be done with the naked eye, through a visual enhancement device like binoculars and telescopes, or by listening for bird sounds.
Birdwatching often involves a significant auditory component, as many bird species are more easily detected and identified by ear than by eye. Most birdwatchers pursue this activity for recreational or social reasons, unlike ornithologists, who engage in the study of birds using formal scientific methods.
There's bird vocalization
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, (relatively complex) songs are distinguished by function from (relatively simple) calls.
and birding by ear
Birding by ear is a skill that can take years to master, but is worth the wait—it compliments the visual identification process in many ways. An advanced birder can walk through a forest or field and record bird species without actually seeing them. In most cases, a bird's song is diagnostic—you can identify the species from its song or call. For some groups made up of similar-looking birds, such as the Empidonax flycatchers, their song is the surest, or possibly only, way to identify which species you've encountered.
Every reputable bird identification and behavior site includes physical and auditory components. A bird is not considered fully identified until you know its sounds; and sub-characteristics, such as age and gender, can't even be defined without learning the different vocalizations. Also, each activity is connected to specific vocalizations.
I think Erik wrote a thoughtful answer here, which I appreciated, as that's the whole purpose of conversation. With all due respect, though, I feel that if we are going to be a birding site, we need to allow all of the questions he listed. In fact, I can answer every one of them, but that's because I spend hours each week reading about birds and animals, including what they say and why they say it. Every sound has a meaning and a purpose. The Merriam Webster Dictionary defines anthropomorphize as
to attribute human form or personality to things not human
The truth is that animals (in this case, birds) already have personalities very similar to humans, so we're not anthropomorphizing, we're learning!
Not only do we recognize birds by their sounds, but they recognize us the same way. A fascinating British study by the Avian Biology Research team found that many birds recognize both our sounds and our faces. The National Wildlife Federation has proven that crows and other birds recognize us by our voices, faces and behaviors, to the extent that they can tell the difference between a friendly and unfriendly person just by watching us. (They were scared off by people acting friendly but wearing Halloween masks - very cool!)
If we only want to concern ourselves with animals as they relate to safety, as @David Richerby mentions in his comment, then we have to take birding off the table in general (although there are some birds you have to be careful of in the wild), and I think the community has not shown a desire to do that. However, if we are going to embrace birding, we have to include bird language and bird behavior questions.
As with any topic, we are free to ignore the questions, but that doesn't make them off-topic. I don't like hunting so I don't read those questions. That doesn't make them any less valid for the site. I'm not physically capable of mountain climbing or hiking; have no need for outdoor gear, clothes or boots; never tie knots; don't know what belay or most of the other terms frequently found here mean. I don't like winter so I never ski. That doesn't give me any less respect for this community. In fact, it's a dedicated group of passionate people who genuinely care about each other.
There's no shortage of sites about birds and backyard animals, but I want to be part of building one, especially because of the SE dedication to quality. If we do it right, we could eventually have a strong enough user base to come up in google searches and bring in more animal-lovers searching for knowledge. I feel very sure that, even though there's a very small amount of overlap with Biology, we're poised to be the only SE site that covers these subjects. I've been hesitant to throw a lot of questions out there, mostly because of meta-discussions like this. Also, I don't want to dump a bunch of simple questions just to increase question stats, as others have been accused of doing. However, if the consensus is to keep it up, you'll be seeing a lot more from me, and we'll just have to see what happens! Conversely, if the consensus is that we're not the right site for this, I'll politely abandon the subject, and continue to support by voting and contributing where I can.
Thank you all very much for allowing me to express myself in this way!