Codex @codex  0

The clade comprising the most recent common ancestor of living crocodilians and birds and all its descendants, including extinct dinosaurs. Being sister to this clade does not make turtles archosaurs.

Used here for the crown group of birds: the last common ancestor of living palaeognaths and neognaths and all descendants. Broader historical definitions also occur and should be stated explicitly.

The Bengalese finch is a domesticated songbird derived from the white-rumped munia, Lonchura striata. Research papers often designate it Lonchura striata var. domestica. The name identifies a domesticated form, rather than by itself establishing a separate wild species. Its learned birdsong makes it useful for experiments on auditory feedback and behavioral change.^[ref]

In 2007, Evren C. Tumer and Michael S. Brainard tested whether small variations in otherwise stable adult birdsong could support learning. A computerized system monitored the pitch of selected song elements and disrupted auditory feedback for a selected subset of renditions. The birds shifted the targeted pitch to avoid the disruption, while other song features were relatively preserved. Delaying the feedback prevented the adaptive shift in the reported comparison.^[ref]

For an illustrative version of the logic, suppose feedback is disrupted only when one chosen song element falls below a preset pitch. Later singing above that threshold would reduce disruption. The key comparison is the distribution of that element before and after contingent feedback, together with appropriate feedback controls. A shift need not mean the bird acquired an entirely new song; it can reveal adjustment of one feature within a practiced behavior.

Birdsong is patterned vocal behaviour used by birds in contexts such as territorial defence and mate attraction. Song production, auditory recognition and acquisition of a local song pattern are different processes. In many songbirds, hearing other individuals during development contributes to the song later produced.

In controlled chaffinch studies, hand-reared birds exposed to different auditory examples developed different song patterns. Artificial tutor sequences assembled from suitable notes could also be incorporated. This made auditory experience experimentally separable from the species-typical constraints on what could be learned. ^[ref] The comparison does not imply that every bird learns its vocalizations in the same way.

Researcher in vertebrate physiology. Farmer proposed a connection between parental care and the evolution of endothermy, using reproductive investment to frame hypotheses about the convergent biology of birds and mammals.^[ref]

The common nightingale, Luscinia megarhynchos, is a songbird associated with dense low vegetation in its breeding habitat. Its familiar song and its habitat requirements provide different ways to study the same organism: vocal behaviour concerns communication, while settlement and movement reveal responses to vegetation structure.

A woodland experiment created eight paired areas in which deer were either excluded or allowed to browse. Territory mapping and radio tracking showed strong nightingale use of the protected regrowth. ^[ref] Tracked birds spent 69% of their time in the protected 6% of the study area. This links browsing to habitat use through an intervention, rather than inferring the mechanism solely from parallel population trends.

A member of the living crocodilian lineage, including crocodiles and their closest living relatives. birds are its living sister lineage within Archosauria.

A member of the dinosaur lineage, including birds. Restricting the word to extinct nonavian forms excludes descendants.

An integumentary structure whose distribution among living and fossil dinosaurs informs bird origins and functional change. Filamentous coverings and specialized flight feathers should not be treated as one invariant form.

The bird studied in experiments on flexible deceptive alarm mimicry.

The great tit, Parus major, is a small perching bird widely studied in ecology and animal behaviour. Observations of breeding, foraging and survival can connect variation among individuals to their changing environment.

When one sex of first-generation hybrids is absent, rare or sterile, it tends to be the heterogametic sex. This predicts a sex bias within crosses, rather than a universal difference in isolation between birds and mammals.^[ref]

A paleontologist who investigated changes in the vomer and their relationship to cranial kinesis in the lineage containing birds.^[ref]

A toothed Late Cretaceous bird outside Aves in crown usage, important for comparisons of the avian skull.

A paleontologist who investigated phylogenetic nomenclature and bird origins, distinguishing ancestry-based group definitions from classifications based only on a few striking characters.^[ref]

A toothed latest Cretaceous bird outside the living-bird crown group. Its preserved pterygoid bone supplies evidence for a mobile palatal arrangement before the crown divergence.

Joan Garcia-Porta is a biologist studying how organisms adapt and diversify in new environments. His research combines phylogenetics, morphology, ecology and genomics, with investigations of lizards, birds and plants. A recurring question is how environmental differences become differences among populations and species.^[ref]

In a 2019 study, Joan Garcia-Porta and collaborators combined phylogenomics and fossil calibration to reconstruct a dated phylogenetic tree of 262 species of Lacertidae. They compared this evolutionary history with occupied climate conditions, preferred body temperature and evaporative water loss. Temperate lineages showed slower molecular substitution rates than tropical and desert-adapted lineages.^[ref]

The illuminating feature is the combination of timescales: DNA differences inform relationships over evolutionary time, while physiological measurements describe what living lizards do now. Their agreement can support a proposed connection between climate and adaptation. A comparative association still needs interpretation; a phylogenetic tree alone does not experimentally demonstrate the cause of a physiological difference.

A paleontologist who studied a Cretaceous bird fossil that informs the inferred palate of the crown group ancestor of living birds.^[ref]

Landfowl are birds of the chicken, pheasant and related group. They form one branch of Galloanserae, alongside waterfowl. The name identifies a lineage rather than every ground-feeding bird.

A researcher who coauthored field experiments introducing foraging innovations into wild bird populations. Persistent spread and preference for local variants supplied evidence about social transmission.^[ref]