Like father,like son?Similarity of syllable repertoires and structures in the songs of first-year male Tree Pipits and their potential tutorsOA

Birdsong in oscine passerines is socially learned,but the relative influence of different tutors in the wild remains unclear for many species.We examined song acquisition in the Tree Pipit(Anthus trivialis:Motacillidae),a migratory passerine with critical-period learning and temporally stable,individually unique syllable repertoires.Through a long-term monitoring study(2016–2025)in eastern England,we analyzed the repertoires of 413 males,including 22 ringed as nestlings and recorded later as adults.For most of these focal males,we identified three potential tutor groups:social fathers(territorial males affiliated to the focal males''nests),natal nest neighbours,and territory neighbours in the first breeding season.Repertoires of studied males were described by the presence/absence of visually classified syllable types,and structural similarity of the two most variable syllable categories was quantified using dynamic time warping.Assessment of the similarity of syllable repertoires suggested that male Tree Pipits learn from multiple local males rather than selecting one specific tutor or preferred tutor group.Repertoire composition and structural similarity of one syllable category(but not the other)indicated higher similarity of focal males''vocalization to those of natal nest neighbours than to those of randomly selected locally co-occurring males;this pattern,however,was driven only by a subset of focal males.Sons''songs were never very similar to those of their social fathers,and siblings from the same nests always developed dissimilar repertoires.Structural similarity in one complex syllable category did not predict similarity in the other,also indicating that syllables tend to be learnt from different tutors.When assembling their repertoires,young male Tree Pipits develop individually unique characteristics while reflecting local acoustic traditions.Combined with strong site fidelity of both young birds and adults,learning from various local sources likely contributes to fine-scale geographic variation in the studied species''song,detectable even within the studied region between areas separated by ca.10 km.