title: Trait-mediated trophic cascade creates enemy-free space for nesting hummingbirds.
abstract: The indirect effects of predators on nonadjacent trophic levels, mediated through traits of intervening species, are collectively known as trait-mediated trophic cascades. Although birds are important predators in terrestrial ecosystems, clear examples of trait-mediated indirect effects involving bird predators have almost never been documented. Such indirect effects are important for structuring ecological communities and are likely to be negatively impacted by habitat fragmentation, climate change, and other factors that reduce abundance of top predators. We demonstrate that hummingbirds in Arizona realize increased breeding success when nesting in association with hawks. An enemy-free nesting space is created when jays, an important source of mortality for hummingbird nests, alter their foraging behavior in the presence of their hawk predators.
authors.affiliation: Yanayacu Biological Station & Center for Creative Studies, Cosanga, Napo, Ecuador. ; Department of Biology, University of Nevada, Reno, NV 89557, USA. ; Department of Natural Resources, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Harold F
authors.initials: HF
authors.lastname: Greeney
authors.affiliation: Hummingbird Monitoring Network, P.O. Box 115, Patagonia, AZ 85624, USA.
authors.forename: M Rocio
authors.initials: MR
authors.lastname: Meneses
authors.affiliation: Department of Biology, Trent University, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: Chris E
authors.initials: CE
authors.lastname: Hamilton
authors.affiliation: Yanayacu Biological Station & Center for Creative Studies, Cosanga, Napo, Ecuador.
authors.forename: Eli
authors.initials: E
authors.lastname: Lichter-Marck
authors.affiliation: Department of Natural Resources, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: R William
authors.initials: RW
authors.lastname: Mannan
authors.affiliation: P.O. Box 16426, Portal, AZ 85632, USA.
authors.forename: Noel
authors.initials: N
authors.lastname: Snyder
authors.affiliation: P.O. Box 16426, Portal, AZ 85632, USA.
authors.forename: Helen
authors.initials: H
authors.lastname: Snyder
authors.affiliation: Hummingbird Monitoring Network, P.O. Box 115, Patagonia, AZ 85624, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Wethington
authors.affiliation: Department of Biology, University of Nevada, Reno, NV 89557, USA.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Dyer
keywords: Accipitridae; Corvidae; Trochilidae; avian biology; life history evolution; mesopredator release; nest success; nesting association