The sound made by a tailor bird is called "cheeup-cheeup-cheeup". Let's explore this answer in detail:

Identification of the sound:
The sound made by a tailor bird is a distinctive "cheeup-cheeup-cheeup" sound. This sound is often described as a repetitive and high-pitched call.

Reason behind the sound:
The tailor bird produces this sound primarily for communication purposes. The male tailor bird uses this call to attract and communicate with a potential mate during the breeding season. This sound serves as a way for the tailor bird to establish its presence and to indicate its availability for mating.

Unique characteristics of the sound:
The "cheeup-cheeup-cheeup" sound made by the tailor bird is unique and easily recognizable. It is a repetitive call that is often heard in the early morning or late evening when the bird is most active. The sound is relatively loud and can carry over a considerable distance, allowing the tailor bird to communicate effectively with other birds in its vicinity.

Comparison with other bird sounds:
While different bird species have their own unique calls, the "cheeup-cheeup-cheeup" sound made by the tailor bird can be distinguished from other bird sounds. For example, the hoot of an owl (option B) is a deep and resonant sound, while the call of a crow (option C) is a harsh and cawing sound. Similarly, the sound made by a dove (option D) is a soft and cooing sound. Therefore, the correct answer is option A, "cheeup-cheeup-cheeup".

Conclusion:
The tailor bird is known for its distinctive "cheeup-cheeup-cheeup" sound, which it uses for communication purposes, particularly during the breeding season. This sound is unique and easily recognizable, setting it apart from the sounds made by other bird species.