Nest Usurpation Varies By Species

Proportion of nest attempts by native host species usurped by non-native European Starlings and House Sparrows. Asterisks above columns indicate that House Sparrows and European Starlings usurped nests at statistically different levels; no asterisks indicate similar levels of impact from starlings and sparrows. Nest samples: n = 3,156 bluebirds; n = 1,468 Tree Swallows; n = 412 Purple Martins; n = 81 American Kestrels; n = 439 House Wrens; n = 19 Northern Flickers; n = 164 chickadees; n = 37 titmice; and n = 46 Bewick’s/Carolina Wrens.