Responses of migratory species and their pathogens to supplemental feeding

Abstract

Migratory animals undergo seasonal and often spectacular movements and perform crucial ecosystem services. In response to anthropogenic changes, including food subsidies, some migratory animals are now migrating shorter distances or halting migration altogether and forming resident populations. Recent studies suggest that shifts in migratory behaviour can alter the risk of infection for wildlife. Although migration is commonly assumed to enhance pathogen spread, for many species, migration has the opposite effect of lowering infection risk, if animals escape from habitats where pathogen stages have accumulated or if strenuous journeys cull infected hosts. Here, we summarize responses of migratory species to supplemental feeding and review modelling and empirical work that provides support for mechanisms through which resource-induced changes in migration can alter pathogen transmission. In particular, we focus on the well-studied example of monarch butterflies and their protozoan parasites in North America. We also identify areas for future research, including combining new technologies for tracking animal movements with pathogen surveillance and exploring potential evolutionary responses of hosts and pathogens to changing movement patterns. Given that many migratory animals harbour pathogens of conservation concern and zoonotic potential, studies that document ongoing shifts in migratory behaviour and infection risk are vitally needed.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'.

Fitness consequences of different migratory strategies in partially migratory populations: A multi‐taxa meta‐analysis

“…Changes in seasonality—particularly warmer winters in the Northern Hemisphere (IPCC, )—could plausibly alter the fitness costs associated with enduring a (formerly) harsh winter or undertaking migration (Berthold, , ). Milder winters (Nilsson, Lindström, Jonzén, Nilsson, & Karlsson, ) and year‐round availability of artificial food sources (see Satterfield, Marra, Sillett, & Altizer, ) may render it unnecessary to undergo the costs of migration to escape unfavourable conditions, while advancing spring temperatures also favour residents, as they are less likely than migrants to suffer phenological mismatches (Pulido & Berthold, ). By forgoing migration, residents are better able to exploit earlier optimal conditions, on which migrants may miss out if unable to advance sufficiently their spring arrival (Møller et al, ).…”

Partial migration in a subtropical wading bird in the southeastern United States

“…, Satterfield et al. ). Changes in migratory patterns might be expected both through adaptation and behavioral plasticity (Pulido , Ghalambor et al.…”

“…The wood stork population is facing environmental change pressures in many regards, from alterations of the natural hydrological dynamics in the Everglades (Kushlan 1987, Sklar et al 2001, Sklar 2005 to increasing urbanization (Hefner and Brown 1984, Reynolds 2001, Terando et al 2014, to which the population might respond in the long run by altering migratory patterns. This is an increasingly documented phenomenon in bird populations in response to various drivers, including climate change, changes in resource phenology, and supplemental feeding (Cotton 2003, Visser et al 2009, Satterfield et al 2018. Changes in migratory patterns might be expected both through adaptation and behavioral plasticity (Pulido 2007, Ghalambor et al 2007, Charmantier and Gienapp 2013.…”

Artificial light at night amplifies seasonal relapse of haemosporidian parasites in a widespread songbird

“…Examining how ALAN affects cycles of latency and reactivation in other host and parasite systems, such as Borrelia burgdorferi and arboviruses in songbirds [64,65] or henipaviruses and herpesviruses in bats [66,67], could inform diseases risks relevant for wildlife conservation, domestic animal health, and human health. Such work could be especially informative for synanthropic wildlife and migratory species that are increasingly becoming sedentary in anthropogenic habitats [68]. Tables Table 1.…”