Our last post shared some pretty intense videos of predation events at nests. In both videos all of the chicks got eaten, and the parents either fled or did not approach the nest while the predator was there. The badger and the 13 lined ground squirrel weren’t challenged as they made off with nestlings. It’s not always like this, though. It turns out that bird parents respond differently depending on who is trying to eat their chicks.
While adult birds and eggs are vulnerable during incubation, they are at even greater risk after chicks hatch. Most of our grassland birds are altricial as chicks, and need to stay in the nest long enough to be reasonably mobile when they fledge. However, chicks are also very vulnerable in the nest: they stay in one place, and the noise and activity surrounding the nest can attract predators. These birds need to balance the benefits of staying in the nest until they are able to fly to forage and escape predators with the potential risks of being found by predators while still in the nest.