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There is NO definitition of NON Passerine. It is
simply all the bird orders apart from one (which happens to be the largest). We
could also say NON Falconiform but it would not have the benefit of convenience.
Just like "Invertebrate" are all animals that are not vertebrates and
invertebrates don't have any defining features apart from the quality of
exclusion. There is no feature that defines either taxon.
Passerines are one of several (about 28) orders
of birds. They are defined by features of their feet (four toes, three face
forward, one back, all joined at the same level and without webs and unjoined
beyond that (except that our Treecreepers have partly joined toes, called
syndactylous). Passerines' toes close automatically with flexure of the ankle.
Also they share features of their syrinx. Beyond that presumably there are all
sorts of biochemical, chromosomal and similar features that indicate
relationship.
By the way, most bird orders can be easiest
picked by the structure of their toes.
I also have a theory that all passerines fly
with their legs (actually their feet) flexed forward (pointing towards the
chest) at the ankle joint, whereas non-passerines fly with their legs (actually
their feet) held straight backward (pointing towards the tail) at the ankle
joint. It is my theory but I have never seen any exceptions to this. Does anyone
out there have other ideas?
Philip
mark kliene
wrote:
> mark kliene wrote:
>
> > Hi all,
>
> Could someone be so kind as to provide me with the definitive
definition
> > (tautology)
> > of what constitutes a non -
passerine.
> > Appreciation in advance,
> >
> >
Mark Kliene.
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