Comparative analysis of passerine feather traits: data and script

Tropical bird species are characterised by a comparatively slow pace of
life, being predictably different from their temperate zone counterparts
in their investments in growth, survival and reproduction. In birds, the
development of functional plumage is often considered energetically
demanding investment, with consequences on individual fitness and
survival. However, current knowledge of interspecific variation in feather
growth patterns is mostly based on species of the northern temperate zone.
We evaluated patterns in tail feather growth rates (FGR) and feather
quality (stress-induced fault bar occurrence; FBO), using 1518 individuals
of 167 species and 39 passerine families inhabiting Afrotropical and
northern temperate zones. We detected a clear difference in feather traits
between species breeding in the temperate and tropical zones, with the
latter having significantly slower FGR and three times higher FBO.
Moreover, trans-Saharan latitudinal migrants resembled temperate zone
residents in that they exhibited a comparatively fast FGR and low FBO,
despite sharing moulting environments with tropical species. Our results
reveal convergent latitudinal shifts in feather growth investments
(latitudinal syndrome) across unrelated passerine families and underscore
the importance of breeding latitude in determining cross-species variation
in key avian life-history traits.