Tropical montane birds have increased nesting success on small river islands

Abstract

Predation is the most important cause of nest failure in birds, and variation in predation risk has been associated with changes in nesting behaviors such as nest-site selection. Some birds choose favorable breeding sites on oceanic or large lake islands to increase their nesting success, but we do not know whether river islands with smaller water barriers provide similar “safe” conditions that decrease predation risk. We tested this in tropical birds by comparing daily survival rates (DSR; i.e. the probability that a nest will survive a single day) and predators identified at nests among bird species that nest on river edges and islands in the Andes. We monitored natural nests of 9 species and placed 70 artificial nests of different shapes (dome, cup, and ground nests) on islands and along river edges. We found that nest survival rates were greater on islands than on river edges for both natural nests (0.989 ± 0.004 vs. 0.0975 ± 0.004) and artificial nests (0.977 ± 0.007 vs. 0.944 ± 0.012). Isol..

Breeding biology of two wagtail subspecies on Ulleung Island, Korea: Amur Wagtails, Motacilla alba leucopsis and Black-backed Wagtails, M. a. lugens

“…The island can provide isolation from avian nest predators (i.e. snakes and mammals), reducing the risk of predation (Fontaine and Martin 2006 ; Ocampo and Londoňo 2015 ). In addition, human beings as well as predation were main causes of nest failure in a population of Central Finland (Leinonen 1973 ).…”

Birds of Two Oceans? Trans-Andean and Divergent Migration of Black Skimmers (Rynchops niger cinerascens) from the Peruvian Amazon

“…Elsewhere, foxes have been shown to impart strong control over seabird colonies [ 54 ], and increases in gull and Bald Eagle populations are correlated with ongoing declines in skimmers and other colonial waterbirds breeding in Virginia, USA [ 55 ]. While nesting success for passerines is generally low in tropical forests [ 56 ], skimmers can benefit from nesting on river islands [ 57 ] and from multi-species defense provided by allies, including the Large-Billed Tern ( Phaetusa simplex ) and Yellow-Billed Tern ( Sterna superciliaris ) [ 29 ]. The latter two species co-occur across the entire Amazon basin, yet neither appears on the Pacific Coast.…”

Effects of Damming on Long‐Term Development of Fluvial Islands, Elbe River (N Czechia)

“…Kauffman et al (1997) have shown that many species have developed adaptive strategies to inhabit riparian and in-stream habitats, while recovering from disturbances caused by hydrological extremes. Fluvial islands may act as natural habitats and refuge for both plant communities (Barnes, 1985;Cooperman and Brewer, 2005) and birds (Lokemoen and Woodward, 1992;Ocampo and Londoño, 2015).…”