Ben Creisler
Some recent avian-related papers:
=====
The origin, distribution, and function of biological diversity are fundamental themes of ecology and evolutionary biology. Research on birds has played a major role in the history and development of these ideas, yet progress was for many decades limited by a focus on patterns of current diversity, often restricted to particular clades or regions. Deeper insight is now emerging from a recent wave of integrative studies combining comprehensive phylogenetic, environmental, and functional trait data at unprecedented scales. We review these empirical advances and describe how they are reshaping our understanding of global patterns of bird diversity and the processes by which it arises, with implications for avian biogeography and functional ecology. Further expansion and integration of data sets may help to resolve longstanding debates about the evolutionary origins of biodiversity and offer a framework for understanding and predicting the response of ecosystems to environmental change.
=========
Tomasz SkawiÅski, Bartosz Borczyk & Lucyna HaÅupka (2020)
Postnatal ossification sequences in Acrocephalus scirpaceus and Chroicocephalus ridibundus (Aves: Neognathae): The precocialâaltricial spectrum and evolution of compound bones in birds.
Journal of Anatomy (advance online publication)
doi:
https://doi.org/10.1111/joa.13303https://onlinelibrary.wiley.com/doi/10.1111/joa.13303Although the development of the avian skeleton has attracted considerable attention, most of the studies have been concentrated on the embryonic period, while studies on the postnatal period are rare. We studied the postnatal development of the skeleton in two phylogenetically distant birds, an altricial passerine Acrocephalus scirpaceus and a semiprecocial charadriiform Chroicocephalus ridibundus. The neonates of the former, despite being altricial, have wellâossified skeleton--the degree of development approaches that of the semiprecocial gull. However, after hatching the limb bones (particularly those of the hind limb) ossify earlier in the gull which is probably related to faster acquisition of locomotor abilities. We have observed that, in contrast to previous reports from neognathous birds, in the ankle of the gull, the ascending process fuses with the astragalus rather than with the calcaneum. This type of development is present in palaeognaths and nonavian dinosaurs but has not yet been reported in neognaths. This indicates a greater diversity within Neognathae and suggests a more complex scenario for the evolution of the avian ankle. However, data from a greater number of species are needed to establish the developmental sequence ancestral for neognathous birds. Furthermore, the sequence of bone fusions in the wrist of Acrocephalus is similar to the fossilâdocumented evolutionary sequence observed in the phylogeny of early birds, with the semilunate carpal and major metacarpal fusing first, followed by the alular metacarpal fusing with the major metacarpal and then the major and minor metacarpal fusing proximally. These data underscore the importance of developmental studies for reconstructing the evolutionary history.
=========
Prior to the inception of the Cape south-coast ichnology project, only one avian tracksite had been reported from South Africa. An additonal twenty-nine sites have now been identified. Although there are limitations and challenges inherent in the study of fossil avian tracks, these tracks have the capacity to complement the traditional skeletal fossil record. Six of these tracksites exhibit the tracks of large avian trackmakers. In some of these cases, the tracks are larger than would be anticipated from an understanding of extant birds in the region and from the skeletal fossil record. This raises the possibility of large Pleistocene forms of extant taxa, and of Late Pleistocene avian extinctions. In one case, track preservation was of exceptional quality, and allowed the identification of previously unreported flamingo feeding traces.
====
Pioneering research on avian behaviour and cognitive neuroscience have highlighted that avian species, mainly corvids and parrots, have a cognitive tool kit comparable with apes and other large-brained mammals, despite conspicuous differences in their neuroarchitecture. This cognitive tool kit is driven by convergent evolution, and consists of complex processes such as casual reasoning, behavioural flexibility, imagination, and prospection. Here, we review experimental studies in corvids and parrots that tested complex cognitive processes within this tool kit. We then provide experimental examples for the potential involvement of metacognitive skills in the _expression_ of the cognitive tool kit. We further expand the discussion of cognitive and metacognitive abilities in avian species, suggesting that an integrated assessment of these processes, together with revised and multiple tasks of mirror self-recognition, might shed light on one of the most highly debated topics in the literatureâself-awareness in animals. Comparing the use of multiple assessments of self-awareness within species and across taxa will provide a more informative, richer picture of the level of consciousness in different organisms.
News: