[EBB Sightings] Nesting Killdeer?

I have a new job on Pinole Valley Road where it hits the 80.  Almost every day, 1-2 shrieking Killdeer are in the vicinity of the parking lot.  One day last week, I went with a large group to lunch.  Some of my colleagues started walking across the landscaped area between car aisles.  One Killdeer was there and started squawking and puffing out its wings.  It certainly wasn't going to fly away! Makes me think there may be a little nest hidden amongst one of the planted flowering bushes...

Also, the freeway underpass there seems to support both Cliff Swallows and White-throated Swifts.  Not sure if this is unusual.