AASAGACITY.NET
   Knowledge is Empowering
A scoring system to define a species; an evaluation of a taxon/some taxa, using the Sensible Species Definition.  5 points between taxa makes a different species.



Geographic separation/Chance
of cross-breeding
Physical differences Voice

Song/Calls

Habitat preference
Behaviour
including
migration
Known
genetic differences

Total Points
sp
or
subsp

Scoring 0-1-2-3 0-1-2-3 0-1-2-3 0-2-3-4 0-1-2-3 0-2-4-5

A SENSIBLE SPECIES DEFINITION (Anderson 1998 and 2012)
Species are populations that are interbreeding and which are reproductively isolated from other such populations by their reproductive isolating mechanisms.
These may include -
     geographic separation / chance of cross-breeding;
    morphological and plumage differences;
    voice;
    habitat preference;
    behavioural differences such as nest-building, social grouping or migration;
    consistent DNA differences.
Each mechanisms can be weighted according to the strength of difference from a recognised species and given a score between 0 and 5; a total of 5 would give the taxon species status.
0
 
 
 
 
 
1
 
 
 
 
 

2

 
 
  
 
3




4





5




Broad hybrid zone





e.g. Narrow and stable hybrid zone,
or good chance of interbreeding.



e.g A small chance of interbreeding.



No chance of interbreeding.

Feather tracts and/or bare parts a little different,


Feather tracts and/or bare parts noticeably different,


Feather tracts and/or bare
parts very different.

Feather tracts and/or bare
parts completely different.
Not so different voice range and/or song phrases.




Noticeably different voice range and/or song phrases,






Completely different voice range and/or song phrases.
Similar or slightly different habitat preferences.



Noticeably different habitats.







Completely different habitats.
Slightly different behaviour.






Noticeably different behaviour.






Very different behaviour.
Genetic differences are barely measurable.


Genetic differences are measurable.



Genetic differences are larger, e.g. net nucleotide
divergence may be > 3%.

Genetic differences are large enough to probably have non-viable offspring.



Genetic  differences are so great that viable inter-breeding would be impossible.




Collocalia spodiopygia
Comparison of a Universally Accepted Species with Other Taxon such as a Subspecies
 Geographic separation/Chance
of cross-breeding
Physical
 differences
Voice

Song/Calls

Habitat preference

Behaviour
differences

Genetic differences

Total Points
sp
or
subsp
Research -
Collocalia s. spodiopygia  Samoa
Collocalia s. townsendi      Tonga
Collocalia s. assimilis        Fiji
Collocalia s. leucopygius    New Caledonia
Collocalia s. ingens            S. Vanuatu
Collocalia s. epiensis         N & C Vanuatu
Collocalia s. desolatus       Santa Cruz
Collocalia s. reichenowi     S & E Solomons
Collocalia s. noonaedanae  New Ireland & New Britain
Collocalia s. eichorni          Mussau Is
Collocalia s. delichon          Manus Is
Collocalia s. terraeginae     coastal NE Queensland
Collocalia s. chillagoensis   inland NE Queensland
Conclusions -
Bird Life international repeatedly say that intrageneric genetic differentiation alone is an unsatisfactory basis for species recognition. But in their research paper "Phylogenetic relationships amongst swifts and swiftlets: A multi locus approach", 2005, Henri A Thomassen et al indicate that Aerodramus (Collocalia) spodiopygius and Aerodramus (Collocalia) terraeginae are genetically separated.
However, the separation indicated may not be enough to probably have non-viable offspring, and even with the degree of geographical isolation involved, to ensure the degree of reproductive isolation necessary to make a species.


0
1
1
1
1
1
1
1
1
1
1
2
2





0
0
0
0
0
0
0
0
0
0
0
0
0



0
0
0
0
0
0
0
0
0
0
0
0
0






0
0
0
0
0
0
0
0
0
0
0
0
0









0
0
0
0
0
0
0
0
0
0
0
0
0








0
0
0
0
0
0
0
0
0
0
0
1-2?
1-2?








0
1
1
1
1
1
1
1
1
1
1
3-4
3-4










sp










subsp
subsp