Migratory decisions in birds: extent of genetic versus environmental control

Abstract

Migration is one of the most spectacular of animal behaviors and is prevalent across a broad array of taxa. In birds, we know much about the physiological basis of how birds migrate, but less about the relative contribution of genetic versus environmental factors in controlling migratory tendency. To evaluate the extent to which migratory decisions are genetically determined, we examined whether individual western burrowing owls (Athene cunicularia hypugaea) change their migratory tendency from one year to the next at two sites in southern Arizona. We also evaluated the heritability of migratory decisions by using logistic regression to examine the association between the migratory tendency of burrowing owl parents and their offspring. The probability of migrating decreased with age in both sexes and adult males were less migratory than females. Individual owls sometimes changed their migratory tendency from one year to the next, but changes were one-directional: adults that were residents during winter 2004-2005 remained residents the following winter, but 47% of adults that were migrants in winter 2004-2005 became residents the following winter. We found no evidence for an association between the migratory tendency of hatch-year owls and their male or female parents. Migratory tendency of hatch-year owls did not differ between years, study sites or sexes or vary by hatching date. Experimental provision of supplemental food did not affect these relationships. All of our results suggest that heritability of migratory tendency in burrowing owls is low, and that intraspecific variation in migratory tendency is likely due to: (1) environmental factors, or (2) a combination of environmental factors and non-additive genetic variation. The fact that an individual's migratory tendency can change across years implies that widespread anthropogenic changes (i.e., climate change or changes in land use) could potentially cause widespread changes in the migratory tendency of birds.

Intra- and inter-individual variations in flight direction in a migratory butterfly co-vary with individual mobility

“…This gives more credit to the inheritance hypothesis than to the environmental hypothesis. Interestingly, both innate and environmentally induced orientation have been described in migrating birds (Pasinelli et al, 2004;Ogonowski and Conway, 2009) and flight direction depends greatly on the flight direction of the mother. Other experiments are now needed to enable conclusions to be drawn on the mode of inheritance of flight direction in P.brassicae, especially as inherited traits related to migration and dispersal have been suggested to have both a genetic (Spieth and Cordes, 2012) and a non-genetic basis (Ducatez et al, 2012a) in this species.…”

Partial migration and decreasing migration distance in the Hungarian population of the Common Blackbird (Turdus merula Linnaeus, 1758): Analysis of 85 years of ring recovery data

“…The prediction that migration distance decreases over time in this Blackbird population was strongly supported by a decrease of 5.9 km per year in average recovery distance (Figure 2). Although age-and/or sex-dependent latitudinal segregation during winter is a common phenomenon in migrants (Newton 2008), and, based on differences in social dominance, one could expect it to be found in Blackbirds as well (Schwabl 1983, Lundberg 1985, these factors had no significant effects on recovery distance in this population of Blackbirds. Reduction in migration distance has also been reported for the Swedish (Fransson & Hall-Karlsson 2008) and German Blackbird populations as well, only with a lower rate of change (-0.14 km/year) in the latter (Fiedler et al 2004).…”

“…The ratio of migrants to residents usually changes with latitude suggesting that the decision to migrate is linked to winter survival. In the northern hemisphere, species exhibiting partial migration often have populations consisting of predominantly resident individuals at lower lati tudes and populations where most birds migrate at higher latitudes (Newton 2008). At the proximate level, migratory behavior appears to be influenced by a varying degree of interaction between genetic and environmental factors.…”

“…At the proximate level, migratory behavior appears to be influenced by a varying degree of interaction between genetic and environmental factors. For example, strong heritability of migratory behavior may maintain partial migration within Blackcap (Sylvia atricapilla) populations (Berthold & Querner 1982), whereas migration has low heritability in Burrowing Owls (Athene cunicularia) (Ogonowski & Conway 2009).…”

Newly Discovered Seed Dispersal System ofJuniperus cedrusQuestions the Pristine Nature of the High Elevation Scrub of El Teide (Tenerife, Canary Islands)

“…The migratory behavior of birds is linked with genetic factors (Berthold, 1991;Berthold and Helbig, 1992;Pulido, 2007), but the relative contribution of genetic versus environmental variables in controlling the tendency to migrate is still poorly understood. Migration has been studied mainly in birds because they carry out long-distance movements and often return to specific breeding and wintering places each year (Ogonowski and Conway, 2009).…”