We had a couple of killdeer (Charadrius vociferus) nests at Leslie Park this spring. The nests for these birds are really hard to spot. The eggs look like rocks and the mother will run away from the nest when you approach.
Source wikipedia, photo by user:Вasil
Today, I noticed two sets of babies running around. The video is poor because I could not get too close to them, so my phone was zoomed in all the way.