[Externet]

Can the birds singing we perceive as pleasant, melodious, be in birds reality a manifestation as aggressive as dog barking ?

[Halucigenia]

Maybe dogs bark for humans but birds sing for themselves?
dog-bark-origins
The idea is that the harsh bark of a dog has been selected by humans to be a warning to humans.

The "song" of a bird is selected by birds to be a warning or mating call for birds, the fact that humans find it pleasing to the ear is simply a coincidence.
I would suggest that it is like the fact that we find flowers pleasing to the eye whereas flowers (wild ones at least) were selected often by insects to the benefit of both plants and insects. It just happens that our pattern seeking mental processes find the patterns that we see in flowers and hear in birdsong pleasing as a coincidence.
However dogs barking is a pattern that we find displeasing and that is why it has been (maybe quite unintentionally originally) selected in dogs.

Mind you, I sometimes find birdsong quite raucous myself. For example the starlings that roost in the ivy in the courtyard outside my house can make quite an annoying racket - so it is quite subjective as to whether birdsong is pleasant and melodious, anyway.

[michel123456]

 Externet, on 5 February 2012 - 01:57 PM, said:

Can the birds singing we perceive as pleasant, melodious, be in birds reality a manifestation as aggressive as dog barking ?

I have been told that some time ago people blinded captive birds in order to make them sing.

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edit: true, found it here

Quote

Throughout much of its history, certain attributes of the sport have garnered criticism. Early proponents of the sport would blind birds with hot needles in order to reduce visual distractions

The "sport" is Vinkensport.

This post has been edited by michel123456: 5 February 2012 - 08:29 PM