Work with radio transmitters has shown that they make the 2,200 mile trip in less than 48 hours. The male plover returns to the same area where he raised a family the previous summer, and coaxes a female to be his mate. She lays four eggs in a shallow nest cup amidst the lichens, mosses and stunted plants on the tundra. This is a black-bellied plover nest that is hatching out. One of the chicks is so young that it's still wet.
Parents take turns sitting on the eggs and defending their family.
Some birds mount a more vigorous defense. Aleen got her scalp bloodied when she went too close. The study area in Alaska is near the Feather River, north of Nome. Despite the fact that there's sunlight all of the time in June, the birds don't seem to have any problem knowing what time of day it is. The male generally sits on the eggs during the day, and the female gets the night shift.