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Bird papers



Apologies if these have been mentioned on this list...

Pike, A.V.L., Maitland, D.P. (2004). Scaling of bird claws. Journal of Zoology (London). 262(1): 73-81

ABSTRACT: The claw geometry of birds can be used to predict their mode of life. Previous studies, however, have not considered how bird size might affect these predictions. Thus, in the present study, the geometric scaling relationships of bird claws are examined for a variety of extant birds with different modes of life: predatory, climbing, perching or ground-dwelling. Measurements of hind-limb claw radius (i.e. claw size) and claw angle (i.e. claw 'hookedness') of the third digit claw were made on 120 species of bird ranging from 0.0057 kg to 44 kg in body mass. Claw radius was found to be proportional to (body mass)0.34 across all species. Claw angle was found to increase with body mass for predatory and climbing birds (i.e. bigger birds have relatively more hooked claws), and decrease with body mass for ground-dwelling birds (i.e. bigger birds have relatively less hooked or flatter claws). No significant relationship was found between claw angle and body mass for perching birds. Mode of life could not be predicted with any certainty using measurements of either claw radius or claw angle, suggesting difficulty in assigning fossil species such as Archaeopteryx to a specific locomotor category. As claw design should enable the claw to withstand the forces placed upon it, further work is needed to establish the stresses experienced by the claws of different types of bird.


Nudds, R.L., Dyke, G.J., Rayner, J.M.V. (2004). Forelimb proportions and the evolutionary radiation of neornithes. Proceedings of the Royal Society Biological Sciences Series B. 271 (Suppl. 5): S324-S327.


ABSTRACT: Analysis of a comprehensive dataset demonstrates that the brachial index (BI=humerus length/ulna length) of modern birds (Neornithes) varies significantly between clades at all taxonomic levels, yet is strongly correlated with recent phylogenetic hypotheses. Variance in BI at the infraclass level is low, but increases rapidly during the proposed major radiation of neornithines in the Palaeocene and Eocene. Although a BI of greater than 1 is primitive for Neornithes, more basal groups of Mesozoic birds (Confuciusornithidae and some members of the diverse Enantiornithidae) had BIs comparable with those of 'higher' modern clades. It is possible that occupation of ecological niches by these Mesozoic clades precluded the divergence of some groups of neornithines until after the Cretaceous-Tertiary boundary. We suggest that with further analysis and data collection the relationships between flight behaviour, ecology and BI can be determined. Hence, BI may provide a useful tool for characterizing the ecology of fossil birds.


On a completely different subject, Dann Pigdon wrote:

As for cattle: Australian cattle stations are huge (some of them are
larger than small European countries),

Not a huge feat, per se. You don't have to be huge to be larger than Monaco or San Marino, or even Liechtenstein. ;-)




Tim

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