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

Assuming a rate of divergence in mtDNA of 1.6% per million years. (Fleischer et al.1998; also see Lovette 2004; Ho 2007; Weir and Schluter 2008).

From mtDNA analysis, species take from between 0.2 to 5.5m yrs.† ("The Speciation & Biogeography of Birds", Ian Newton, 2003.

MU

Total points
sp
or
subsp

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

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 mtDNA and other genetic 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, or successful breeding is not known to occur where there is breeding overlap.


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 definitely measurable.



Genetic differences indicate larger divergences.

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


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




Trans-Beringian non-passerines
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
These four taxa are mentioned in "The Speciation and Biogeography of Birds", Ian Newton, 2003, p 317, as having marked genetic differences from one side of Bering Strait to the other (Zink et al.1995).
Research -

Numenius phaeopus
Common Whimbrel
Numenius hudsonicus American Whimbrel
Conclusions -
Species status of N. hudsonicus seems warranted. The three other subspecies also have breeding areas isolated from each other in Eurasia and should genetic testing indicate a genetic difference of two or more they will also be considered for speciation.
Research -
Brachyramphus marmoratus
Marbled Murrelet
Brachyramphus perdix Long-billed Murrelet

Larus canus Common Gull
Larus c. kamtschatschensis Kamchatka Gull
Larus c. brachyrhyncus Mew Gull (NW North America)

Picoides tridactylus Eurasian Three-toed Woodpecker
Picoides dorsalis American Three-toed Woodpecker
Conclusions -
The murrelet and the woodpecker have been recognised as species by most authorities for well over a decade. The Mew Gull, which breeds extensively in north-western North America but not in the east, does not quite make it to species level, and remains a subspecies of the Common Gull. †





0
1-2






0
2

0
1
1

0
2-3





0
1-2






0
1

0
0
1

0
1





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
2






0
2

0
0
2

0
2





0
4-6






0
5

0
1
4

0
5-6





sp

sp






sp
sp

sp
subsp
subsp

sp
sp