Using isotopic variance to detect long-distance dispersal and philopatry in birds: An example with Ovenbirds and American redstarts

• Main Authors: Bayne, E.M., Hobson, K.A., Wassenaar, L.I.
• Format: Other/Unknown Material
• Language: English
• Published: 2004
• Subjects: Deuterium; Dispersal; Carbon-13; Feathers; Source-sink populations; Stable isotopes; Philopatry; Canada; Lac la Biche
• Online Access: https://era.library.ualberta.ca/items/7bac1fc8-ef93-4739-848f-867791a0745f; https://doi.org/10.7939/R3S46HH4H

Understanding movement so f individualb irdsb etweenb reedings ites (breeding dispersal) or between natal sites and the site of first breeding (natal dispersal) is crucial to the modelingo f populationd ynamics.U nfortunatelyt,h ese aspectso f demographya rep oorly understoodf or avian species in general, and for migratorys ongbirdsi n particularT. his is because it is often impossible to sample broadly enough to relocate marked birds that have moved. We used stable-hydrogen(8 D) and carbon( 613C)is otope analyseso f the featherso f 139 American Redstarts (Setophaga ruticilla) and 193 Ovenbirds (Seiurus aurocapillus) to evaluate evidence for individuals molting feathers at locations other than their breeding sites from the previous year. We sampled outer rectrices from breeding populations at three extensive boreal forest sites (Prince Albert National Park and Duck Mountain, Saskatchewan, and Lac La Biche, Alberta) and at three isolated forest tracts (Cypress Hills, and Moose Mountain, Saskatchewan, and Turtle Mountain, Manitoba) in western Canada. Based on outliera nalysiso f 6D measurementsw, e found evidence for long-distanced ispersalr anging from 0-29% of individuals. For both species, second-year birds had higher variance in 6D values suggestingt hey had a higher probabilityo f originatingf rom elsewherec omparedt o after-second-yeabr irds.