title: Differential fall migratory routes of adult and juvenile Ipswich Sparrows (Passerculus sandwichensis princeps).
abstract: BACKGROUND
  Island breeding birds present an ideal system for studying migratory movements in passerines because their populations are clearly demarcated, and individuals must depart on migration from a single location. The Ipswich Sparrow (Paserculus sandwichensis princeps) is a subspecies of the Savannah Sparrow that breeds exclusively on Sable Island, Nova Scotia, Canada and winters along the Atlantic coast of North America. We used a network of 34 automated VHF telemetry receivers to track radio-tagged adult and juvenile Ipswich Sparrows from their breeding island southward through the first half of their fall migratory journey.
  
  
  RESULTS
  We compared adult to juvenile timing and routes. We show that juveniles leave the island approximately 24 days prior to adults and remain temporally separated from them during migration through Nova Scotia. Juveniles have different overwater orientations that result in migratory routes with shorter ocean crossings and a longer overall distance travelled compared to adults. Juveniles also have more frequent and longer stopovers, and displayed some reverse migration.
  
  
  CONCLUSIONS
  We demonstrate that migratory routes differ between adults and juveniles, suggesting that routes change as individuals age, possibly through learning or social interactions. These differential routes also suggest that sparrows experience risk in different ways with juveniles selecting shorter overwater flights with less navigational risk at the cost of increased time spent in migration.
authors.affiliation: Department of Biology, Acadia University, Wolfville, B4P 2R6, NS Canada.
authors.forename: Zoe J
authors.initials: ZJ
authors.lastname: Crysler
authors.affiliation: Department of Biology, Acadia University, Wolfville, B4P 2R6, NS Canada ; Canadian Wildlife Service, Environmental Stewardship Branch, Environment Canada, 45 Alderney Drive, Dartmouth, B2y 2N6, NS Canada.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Ronconi
authors.affiliation: Department of Biology, Acadia University, Wolfville, B4P 2R6, NS Canada ; Bird Studies Canada, Port Rowan, N0E 1M0, ON Canada.
authors.forename: Philip D
authors.initials: PD
authors.lastname: Taylor
keywords: Age; Automated telemetry; Ipswich Sparrow; Migration; Route; Songbird; Stopover
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