A limited number of preferred stock issues pay their dividends on a monthly basis instead of on a quarterly basis.
In general there is nothing special with these issues, but “a bird in hand is worth 2 in the bush” and we would rather have the money in our pocket than in the issuers pocket, thus receiving a dividend every month accomplishes our needs. Technically speaking preferred stocks paying monthly dividends yield a bit more over the course of a year than those paying quarterly dividends–but it is not worth worrying about this tiny differential.
Personally, as an investor, I like the dividends that hit my account on a monthly basis. It is just a regular paycheck each month and I like a nice steady flow–but that is just me.
While these particular preferred stocks pay monthly dividends there is nothing else that is different from all other preferred stocks that pay quarterly.
The Yellow coloring on the earliest call date would indicate currently optionally redeemable.