S. R. Faruqi:

In this theme there's a strange kind of melancholy mysteriousness. He hasn't given any reason why when he leaves the nest, he will not come back again. Is it because in him, or in humans, there's a disposition for a kind of search for an enterprise/exploit that keeps them wandering in search of ever-new worlds? Or is it because once he has left home and gone out, then he will become homeless? That is, was it written in his very fate to go from door to door? Or is it because the outside world is so dangerous that once he's entered into that world he'll be doomed to death, and it won't be vouchsafed to him to return? On this last reading see:

{37,3}.

Or again, in the first divan itself there's this verse too [{578,2}]:

va;hshat se merii yaaro ;xaa:tir nah jam(( rakhyo
phir aave yaa nah aave nau-par u;Thaa jo ghar se

[don't be complacent about my wildness, friends
he might come again or might not, the newly-fledged one who has left the house]

Mir was so fond of this theme (of having left home, for it to be impossible to come back again) that he kept on composing it through his whole life. From the second divan [{840,6}]:

pachhtaa))e u;Th ke ghar se kih juu;N nau-damiidah par
jaanaa banaa nah aap ko phir aashiyaa;N talak

[we regretted having left home, for like one with newly-sprouted wings
we were not able to go then/again as far as the nest]

From the third divan [{1299,5}]:

bah rang-e :taa))ir-e nau-par hu))e aavaarah ham u;Th ke
kih phir paa))ii nah ham ne raah apne aashiyaane kii

[like a newly-fledged bird, we rose and became a wanderer
so that we did not again find the road to our nest]

From the fifth divan [{1661,5}]:

aavaarah hii hu))e ham sar maar maar ya((nii
nau-par nikal ga))e hai;N apne sab aashiyaa;N tak

[we became only/emphatically a wanderer from pillar to post; that is,
the newly-fledged ones have all gone as far as their own nests]

It's possible that behind these verses might be Mir's personal experience, because for a significant portion of his life it was not vouchsafed to him to sit in peace.

But the style of these verses has behind it a more expansive atmosphere of melancholy, a universal feeling. It seems that in these verses Mir is expressing not only his own wanderings, but rather those that became, after Adam's fall, the lot of Adam and the children of Adam. Or again, in these verses there seems to be a feeling that the universe and the human world are alien, are strange, and are sources of suffering.

That is, as long as we are shut up in our home (that is, in our origins, or in our personal existences), for that long we are protected. But when we go out into the world, one thing or another will prevent us from returning home. That is, our personality and our existence will undergo a fall/decline. Whether he would be a lost traveler, or there would be the clamor of conquering ever-new stages, or only death-- in any case, once we have left home, we've washed our hands of our original state.

There's a famous [Persian] verse by Vahshi Bafiqi:

'The heart is not a pigeon, that it would come homing back
Whatever roof-edge we have flown from, we have flown away.'

One can be confident that Mir would have had his eye on this verse, and it's possible that Mir profited from it. But from this light/superficial theme Mir created two themes, and both are very deep/serious.

FWP:

SETS == FILL-IN
MOTIFS == HOME; [LOVER AS BIRD]
NAMES
TERMS == THEME

SRF is right to point out the sinister and dangerous possibilities: the bird might not return because he's succumbed to one of the countless perils of the natural world. Or perhaps it's just wandering, just distance that's involved? Or perhaps the bird went so far toward mystical 'self-lessness' that he couldn't find out way back to his own self?

Since the bird is 'like' a little new fledgling, it means that he merely resembles one but is not actually such a fledgling. The verse doesn't permit us to figure out exactly how the bird-speaker is 'like' the new fledgling. Is it simply because he leaves the nest? Is it because he's particularly naive or vulnerable? Is it because he doesn't return? Is it because he cannot return?

It's mainly the tak that makes it sound as if he might have struggled to return, but wasn't able to make it 'that far'. Whatever the situation, the tone is powerfully, effectively ominous. It almost sounds as though the bird wants to spare his hearer from full knowledge of 'where we went'.