Physiological assessment of the effects of changing water levels associated with reservoir management on fattening rates of neotropical migrants at a stopover site

Abstract

We used plasma metabolite analysis to estimate variation in fattening rate in four neotropical migratory songbirds utilising riparian habitat at a dam-impacted stopover in British Columbia, Canada. Our study suggests that although hydroelectric dam operations influence water levels this does not significantly impact fattening rates of birds using these habitats.

Conservation physiology of animal migration

“…Supplemental feeding of birds and ungulates is common in some regions, and engineering feed to suit the nutritional requirements of migrants could provide a short-term solution for loss of stopover habitat, although in the long-term the preservation, remediation or replacement of stopover habitat is the only viable solution ( Smith et al ., 2015 ). Likewise, manipulating water levels in hydroelectric damn drawback areas may influence the extent to which migratory birds can refuel for their migration, although empirical studies of this have not been successful ( Wagner et al ., 2014 ).…”

Body condition and reproductive phenology

“…Measurement of plasma BUTY (mmol.L -1 ) can be completed with a commercially-available enzymatic and colorimetric assay (Megazyme, Ireland, #K-HDBA; Wagner et al 2014). Plasma TRIG can be quantified with a commercially-available enzymatic and colorimetric determination kit (Sigma Aldrich, USA, #TR0100-1KT; Williams et al 2007).…”

Local site variation in stopover physiology of migrating songbirds near the south shore of Lake Ontario is linked to fruit availability and quality

“…Anthropogenic landscape change that alters the availability and continuity of suitable stopover habitats can limit choices for birds during migration, although some studies have found that birds can use urbanized or developed areas during stopovers ( Seewagen and Slayton, 2008 ; Seewagen et al , 2011 ; Wagner et al , 2014 ), and these more anthropogenic habitats can partly substitute for intact habitats for landbirds ( Liu and Swanson, 2014 ). One example of the potential negative consequences of urbanized habitats that may be of particular relevance to migrating birds in autumn is the potential introduction and range expansion of non-native fruit-bearing plants in areas that may serve as stopover sites.…”