Paternal transmission of migration knowledge in a long-distance bird migrant

Abstract

While advances in biologging have revealed many spectacular animal migrations, it remains poorly understood how young animals learn to migrate. Even in social species, it is unclear how migratory skills are transmitted from one generation to another and what implications this may have. Here we show that in Caspian terns Hydroprogne caspia family groups, genetic and foster male parents carry the main responsibility for migrating with young. During migration, young birds stayed close to an adult at all times, with the bond dissipating on the wintering grounds. Solo-migrating adults migrated faster than did adults accompanying young. Four young that lost contact with their parent at an early stage of migration all died. During their first solo migration, subadult terns remained faithful to routes they took with their parents as young. Our results provide evidence for cultural inheritance of migration knowledge in a long-distance bird migrant and show that sex-biased (allo)parental care en route shapes migration through social learning.

The Yellow-browed Warbler (Phylloscopus inornatus) as a model to understand vagrancy and its potential for the evolution of new migration routes

“…Again, these two explanations are not mutually exclusive and vagrants could be a mix of genetically affected individuals and individuals whose orientation system has been modified by non-genetic mechanisms leading to increased variation and novel routes [ 46 , 83 ].…”

The spatial consistency of migratory route and stopover choice in European nightjars quantified by nearest neighbour analysis on multi-annual GPS tracks

“…This suggests that the nightjars oriented towards individual-specific goal areas distributed along the southern desert border. The occurrence of intermediate goal areas has been described before in ospreys, Caspian terns and great reed warblers, suggested to be a result of a repeated use of stopover sites in these habitat-specialists (Alerstam et al 2006, Hasselquist et al 2017, Byholm et al 2022. However, the nightjars did not return to the same stopovers, and tracks in subsequent years were at least tens of km apart.…”

“…If avian migrants balance between safety, energy and time in order to maximize fitness, the degree of spatial consistency may reflect ecological implications of the trade-off between space-use and route choice. Species with specific habitat preferences such as osprey Pandion haliaetus , Caspian tern Hydroprogne caspia and great reed warbler Acrocephalus arundinaceus likely reap a relatively large benefit by revisiting stopovers previously used (Alerstam et al 2006, Hasselquist et al 2017, Byholm et al 2022. In contrast, habitat generalists like aerial insectivorous birds may gain less from experience and exhibit a higher degree of flexibility when selecting stopover sites.…”

A parametric model for estimating the timing and intensity of animal migration

“…While analyzing the distribution of parameter values across a set of individuals (or individual migrations) is fairly straightforward (Figure 6), there is also an opportunity to regress our parameter estimates (particularly, the t i parameters) against covariates. Animal populations display high individual variation with respect to their migratory behaviour (Hanski et al, 2004; Jesmer et al, 2018; Merkle et al, 2019; Byholm et al, 2022), and inter-annual variation in an animal’s environment can cause an individual’s migratory paths to vary from year to year (Tucker et al, 2018; Mallory et al, 2020; Franklin et al, 2022). Similarly, the effects of habitat modification and/or associated disturbance factors could also be assessed.…”