Does hyperthermia constrain flight duration in a short-distance migrant?

Abstract

One contribution of 17 to a theme issue 'Moving in a moving medium: new perspectives on flight'. While some migratory birds perform non-stop flights of over 11 000 km, many species only spend around 15% of the day in flight during migration, posing a question as to why flight times for many species are so short. Here, we test the idea that hyperthermia might constrain flight duration (FD) in a short-distance migrant using remote biologging technology to measure heart rate, hydrostatic pressure and body temperature in 19 migrating eider ducks (Somateria mollissima), a short-distance migrant. Our results reveal a stop-and-go migration strategy where migratory flights were frequent (14 flights day 21 ) and short (15.7 min), together with the fact that body temperature increases by 18C, on average, during such flights, which equates to a rate of heat storage index (HSI) of 48C h 21. Furthermore, we could not find any evidence that short flights were limited by heart rate, together with the fact that the numerous stops could not be explained by the need to feed, as the frequency of dives and the time spent feeding were comparatively small during the migratory period. We thus conclude that hyperthermia appears to be the predominant determinant of the observed migration strategy, and suggest that such a physiological limitation to FD may also occur in other species.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

Heat dissipation rate constrains reproductive investment in a wild bird

“…At the physiological level, such costs include, for example, changes to energy metabolism within cells (Jimenez & Williams, 2014), oxidative stress and subsequent lipid peroxidation (Farag & Alagawany, 2018;Lin, Decuypere, & Buyse, 2006), reduced gamete quality (Hansen, 2009;Hurley, McDiarmid, Friesen, Griffith, & Rowe, 2018), and potentially lifethreatening disturbances to the immune defence system (Farag & Alagawany, 2018;Lim & Mackinnon, 2006). At the ecological level, costs of prohibitively high T b are less well understood, but it is easy to speculate that reduced (Marino, 2004), or temporarily arrested (Guillemette et al, 2016), work rate in anticipation of hyperthermia could make birds more vulnerable to predation during subsequent recovery. Accordingly, relieved constraints on T b regulation in our study resulted in increased investment into both current and future reproduction.…”

“…There are fewer data for birds. However, migrating eider ducks (Somateria mollissima) stop flying when core body temperature (T b ) approaches a hyperthermic threshold and reduce overall activity when their rate of heat storage is high (Guillemette et al, 2016). Moreover, some bird species in warm climes substantially reduce locomotor activity in hot ambient temperatures (Powers et al, 2017;Wiley & Ridley, 2016).…”

Impacts of “supermoon” events on the physiology of a wild bird

“…Methods for logger implantation and removal are described in detail elsewhere (Bevan, Woakes, Butler, & Croxall, ; Guillemette et al, ). Before use, the loggers were encased in paraffin wax and encapsulated in silicon rubber to provide waterproofing and bio‐compatibility.…”

Spatiotemporal effects of logging and fire on tall, wet temperate eucalypt forest birds

“…We selected this trait because, worldwide, migratory species are thought to be among the most severely declining taxa, not only due to climate change and extreme weather, but also other factors like habitat loss (Sanderson et al 2006, Both et al 2010, Runge et al 2015, Barlein 2016, Gilroy et al 2016. At the outset of this investigation, we predicted that migratory species would be more severely affected by increasing amounts of disturbance in the landscape than residents, because the strong physiological demands on migratory taxa that result from long distance travel (see Guillemete et al 2016) could reduce their resilience to increasing amounts of forest perturbation in the landscape. The third trait we examined was diet through comparing insectivores with species that consume other kinds of food.…”

“…At the outset of this investigation, we predicted that migratory species would be more severely affected by increasing amounts of disturbance in the landscape than residents, because the strong physiological demands on migratory taxa that result from long distance travel (see Guillemete et al. ) could reduce their resilience to increasing amounts of forest perturbation in the landscape. The third trait we examined was diet through comparing insectivores with species that consume other kinds of food.…”