Complex sentence: The underwing coverts are mostly dull-white, but the greater coverts are dark and there is a dark brownish bar over the lesser coverts, and the rear tertials upperwing coverts mostly have paler tips with silvery-grey tinge on the greater secondary coverts and tertials.
Split into simpler sentences: The underwing coverts are mostly dull-white, but the greater coverts are dark and there is a dark brownish bar over the lesser coverts. The rear tertials upperwing coverts mostly have paler tips with a silvery-grey tinge on the greater secondary coverts and tertials.