When I first arrived, I saw both Mom and Dad killdeer in M2's territory without sight of any chicks. It's unusal to see them together with no chicks, but not unusual for Dad to be there all alone. I thought I heard at least one chick response to their calls, but it could have been a phoebe. Dad was acting like he was hiding something over by some rocks and brush, but I saw nothing over there. Meanwhile, Mom slipped over to where the chicks originally hatched and began doing alarm calls.
I went over to the "hatching" area and mom constantly did alarm calls and flew outside the area and across the road, doing alarm calls there. I walked about every inch of that area as well as every other area where I last saw the chicks and/or the parents in the past and saw no sign of the chicks. Mom pretty much followed me the whole time, doing alarm calls. I thought I heard at least one or two chicks respond, but it's hard to tell when there are phoebes in the area and they often sound like the chicks, too.
Mom did this all by herself, constantly making calls the whole time someone was in any of the areas where the chicks have been seen in the last week. Dad did not join in or come to her aid. She did not do any broken wings acts, trilling, or anything else that would indicate that I had ever gotten close to any of the chicks. I left without seeing any trace of them.
Since the chicks have reached a week old, an important milestone, this change in behavior may be completely normal. The chicks know the area and what to eat, they know what to do if a human approaches them on foot and they probably know that we can't find them in the brush. Also, they probably can better regulate their temperature, so they don't need mom or dad's warmth as much as they used to. So, now, they're allowed to roam around on their own with only one parent to watch out for possible predators.
However, they are still extremely small I am having trouble believing that their parents would just leave them like that. It's also possible that all three chicks have died/disappeared/were stolen by people and the parents have no idea where they are anymore. Or, it could be that the parents know exactly where each chick is and deliberately hide them in the morning and do alarm calls to warn the chicks to stay hidden. I've noticed that was how they protected their nest. They would do alarm calls every time a person got within sight of the nest and not exactly where the nest was at, but anywhere around there. If this is the case, it will be very difficult for me to find the chicks again until they're almost grown.
It would be hard to believe that all three chicks, making it through the toughest part of their life, would suddenly be eaten or disappear in less than 24 hours. I do think, though, that the parents will become less and less protective of the chicks during the next week and a half. By two and a half weeks, the chicks may be totally on their own with a parent keeping one eye out for them, but not constantly staying in the area.
If I don't see them again, at least I've enjoyed their first week of life, but I'm holding out hope that they will be seen again when they're older.
**Afternoon update**. I looked again in the late afternoon, a time I rarely ever visit this area. At first, no sign of any killdeer could be seen, though one was heard in the area where I last saw the chicks doing alarm calls when someone walked by. Later, I saw Dad killdeer fly over to his feeding area where he called a couple of times and became quiet. As I left, I thought I heard him doing alarm calls close to the fenced off area, but could not be sure.
There are two other killdeer couples over there as well. No sign of the chicks or Mom killdeer at all. It's entirely possible that they chicks were successfully brought over through the fenced off area and are living there totally out of reach. But, it's highly unlikely as there are still way too many predators in that area. Will try again tomorrow morning, early. I will also be attempting to check out the other killdeer on the other side of the lake, too. A new construction project is due to begin there and I want to make sure the baby killdeer will not have issues as they will be tearing out trees and other plants there.