Many animal species elicite characterists such as a male peacock for example, they posess vibrant plumages to show their fitneas, however such appendages hinder the animals survivability thus making them weaker in terms. So what do you think could have caused this? As some evidence suggests that this could be controlled by mating preference  but that suggest that animals are able of conscious thought?

i came across this while reading a book on mating strategies that provoked my interest in the matter! And thank you for your time! :-)

Female preference is generally thought to be the driver of most "flashy" male signals like the peacock's tail. In simple terms females prefer a signal (e.g. big tails) and then this preference actually imposes sexual selection on teh male trait causing it to evolve. There are a number of competing hypotheses and models that differ primarily in why the female prefernece should occur in the first instance, but certainly there is no doubt that it does.

More here if you want it
https://en.wikipedia.org/wiki/Mate_choice

In terms of "conscious thought" this is not really a prerequisite for exhibiting a behavioural preference, animals (including ourselves) do have inbuilt sensory biases and these could be involved. However, it is also very much the case that animals possess cognitive abilities comparable in form (if not always in performance) to ourselves and are able to, for instance, discriminate between males of different "quality". I think the concept of "conscious though" is perhaps problematic to apply as it is not very well defined, but certainly animals can be "intelligent" in the lay sense of the word.