I captured this Black Oystercatcher pair in profile as they scrambled around some rocks in Pacific Grove. They paused for just a second, in a perfect, pointed posture, one against the other.
The bird in back has an eye fleck, which usually means female. From the Journal of Field Ornithology:
“ … we found that eye flecks were sex-linked. Using an eye-fleck model where all females have full eye flecks and males have either slight eye flecks or no eye flecks, we correctly assigned the sex of 117 of 125 (94%) oystercatchers.”
[Olympus EM1markII + m.zuiko 100-400mm]