I’m going to show you some pictures. They will be cute. Ready?
How do these adorable critters relate to my bird research?
They eat my birds.
Deer mice like the one in the top photo were common in my field site in Ithaca, NY, where I studied House Wrens. Not uncommonly, whole broods of chicks would simply disappear. The main culprits were probably snakes, weasels, and deer mice. (The deer mice also liked to nest in the nestboxes we put up, as you can see here, even though we put slippery stuff on the poles holding up the nestboxes to keep the mice out.)
Juncos nest on the ground, making them even easier to reach than House Wrens, and at least two sources (1,2) name chipmunks as among their primary predators. I haven’t seen this yet; but two of my labmates study chipmunks in or near my study sites, so between them and me, there’s a good chance someone will find evidence of a chipmunk-junco predation event this summer.
1. Ketterson ED, Nolan Jr V. 1992. Hormones and life histories: an integrative approach. American Naturalist 140 suppl:S33-S62.
2. Martin TE. 2001. Abiotic vs. biotic influences on habitat selection of coexisting species: climate change impacts? Ecology 82(1):175-188.