Q. Is a cohen visiting a shul obliged to announce that he is a cohen so he will be called first to the Torah reading, when the gabay does not ask if a cohen is present?

A. P’ri Megodim (139 : Eishel Avrohom 2) rules that a Cohen is not required to announce he is a Cohen, so he will be honored by being given the first aliya. He compares it to the improper demand of a Cohen to be given his due parts on the korbonos (Yuma 39a, Chulin 133a). Other Poskim disagree and differentiate between a desired spiritual honors and material gift (Tiferes Adam 3: 8). Piskei Teshuvos (135: 8) maintains that there is no obligation for a Cohen to indicate his status when not asked, even if a Yisroel will be granted the first aliya.
Horav Shlomo Miller’s Shlit’a opinion is that it is preferable he should inform he is a Cohen.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a