Comparison of Azorean atlantis with Other Forms

Comparison of Azorean atlantis with Other Forms

Table 1 shows how features of Azorean atlantis compare to those of the other two proposed Atlantic forms -- Iberian atlantis and Southern atlantis. It will be noted that only two features of Azorean atlantis are tentatively identified as being distinctive:

In adults smaller mirror on P10, more often no mirror on P9 (only 13% with mirror here in one study, 2% in another);
In older immatures from second-winter to third-winter, extensive heavy streaking on entire head and upper neck sometimes extending to lower neck; such streaking appears to extend to fourth-winters and possibly adults as well.

Three features are closer to Southern atlantis:

Mantle shade/colour; wing tip P10/P9; wing tip P6-P8.

One feature does not provide any distinction:

Biometrics.

Four features are too poorly known to provide any information:

Wing tip P5; wing tip P4; calls; timing of head streaking.

One feature possibly favours Iberian:

Timing of primary moult

Four features are closer to Iberian:

Head streaking; timing of breeding; genetics; tertials.

On this analysis it is not possible to classify Azorean atlantis as either Iberian or Southern atlantis. It does have a small number of characteristic features so should perhaps be treated as a form in its own right: Azorean atlantis.

Obviously further information is required for a more definite view of the atlantis of the Azores.

	Form of atlantis to which Azorean atlantis is closer	Distinguishing feature of Azorean atlantis	Comments	References
Adults
Mantle shade/colour	Southern			Mantle shades
Biometrics	Southern/Iberian			Biometrics
Wing tip P10/P9	Southern	Smaller mirror P10, more often no mirror P9 (only 13% with mirror here, Teyssèdre, 1983); one study (per Dubois, 2001) reports only 2% have mirror on P9 compared to 10% in Madeira		Wing Tips ; Dubois (2001)
Wing tip P6-P8	Southern		atlantis has 60% more black on wingtip than smithsonianus, compared to 40% for michahellis	Wilds & Czaplak (1994)
Wing tip P5	??
Wing tip P4	??
Calls	??
Head streaking	Iberian	Possibly in fourth-winters mainly, extensive heavy streaking on entire head and upper neck sometimes extending to lower neck; further work needed to see how many adults have strongly streaked heads		Dubois (2001); Wilds & Czaplak (1994); Dubois
Timing of head streaking	??
Timing of primary moult	Iberian?		Very slightly later than Southern -- no more than 2 weeks (one feather). Timing of Iberian atlantis moult poorly known.
Timing of breeding	Iberian			Bannerman & Bannerman (1966); Bannerman Azores
Genetics	Iberian		Included in northern atlantis (with Iberian forms)	Liebers, Helbig, and de Knijff (2001); Genetics
2nd and 3rd years
Head streaking	Iberian	Extensive heavy streaking on entire head and upper neck sometimes extending to lower neck		Dubois (2001); Dubois
1st years
Head streaking and general duskiness	Iberian			Dubois (2001); Dubois
Many tertials have fine pale fringes or pale indentations or notches.	Iberian			Dubois (2001); Dubois
Views of Earlier authorities
Dwight	Southern			Dwight
Stegmann	Southern/Iberian			Stegmann
Bannerman	Southern/Iberian			Bannerman

Table 1: Comparison of Azorean atlantis with other forms of atlantis

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