Comparison of Mantle Shades from Various Sources

Comparison of Mantle Shades from Various Sources

Table 1 shows the mantle shades reported by a total of seven studies for 11 different taxa, including one hybrid. On the Munsell scale, lower values indicate darker shades; on the Kodak, Dwight greyness and Dulux scales, lower values indicate lighter shades. Jonsson (1998) indicates the following correspondence between the Munsell and Kodak scales: Kodak 5 = Munsell 6; Kodak 7 = Munsell 5. For scoring from Rossiter (2001) the lightest shade is scored 1, the next darker shade 2 and so on up to the darkest shade of 8. See shades and discussion for details. The Dulux scale used is a graduated blue-grey colour scheme. Dwight (1925) used a nine-point greyness scale and the Kodak scale has 19 points.

source	Bermejo (1999)	Barth (1966); see Lewis (2000)	Hampton (1999)	Howell (2003)	Jonsson (1998)	Dwight (1925)	Rossiter (2001)
scale	Munsell	Munsell	Munsell	Kodak	Kodak	Dwight greyness	Dulux
meaning	Lower = darker	Lower = darker	Lower = darker	Higher = darker	Higher = darker	Higher = darker	Higher = darker
argenteus		5.6-6.2		4-5			1.5 (1-2)
argentatus		5.1-5.4 (4.4-5.6)	5.0	5.5-7	5.6	2
Canta-bricans							2
Iberian atlantis	5.25-5.50						4.5 (4-7)
Azorean atlantis				7-8
Southern/ Azorean atlantis	4.25-4.50	4.4-4.5	4.0-4.5		7.0-7.5	5	6.5 (5-7)
argenteus x graellsii				7
michahellis	5.5-6.0	5.1-5.3	5.0-5.5	6-7	6.3 (6.0-7.0)	3	2.5 (2-3)
cachinnans					6.0 (5.0-6.5)	3
graellsii		3.5-3.8 (3.3-4.1)	3.5	9-11		6
intermedius	2.7-3.1 (2.5-3.3)	2.7-2.8		11-13

Table 1: Mantle shades of Gulls from Various Sources

Notes:

Where two values or ranges are given, the first indicates the central range and the second in brackets the overall range.

Bermejo (pers. comm.) also considered the birds in south Morocco and western Sahara to have very similar mantle shades to those of Iberian atlantis. Rossiter (2001) found Atlantic Moroccan birds were similar to those from the Canaries except for those in the michahellis/atlantis intersection zone at Tanger (which were paler).

Dubois (1987) noted the pale mantle colour of cantabricans relative to michahellis. However, Teyssèdre (1983) thought that cantabricans had partial overlap with michahellis on its mantle colour with a tendency to be paler. Rossiter (2001) suggests that some overlap does occur although in general cantabricans is paler than michahellis.

The sample size for argenteus x graellsii hybrids (Howell, 2003) was only two birds.

Results:

All sources agree the following comparisons are true for the darkness of the mantle shade:

intermedius >= graellsii >= Southern/Azorean atlantis >= Iberian atlantis >= michahellis >= cantabricans >= argenteus

The >= shows limited overlap with the darkest of a paler taxon having a similar mantle shade to the palest of the next darker taxon.

The only specific study of Azorean atlantis -- Howell (2003) -- shows that it is one shade darker than michahellis -- the same difference as found between atlantis and michahellis in other studies. Hence no significant difference is apparent between Azorean and Southern atlantis. The exact sources of specimens for most studies are unfortunately not known.

Sources for Mantle Shades:

Barth, E K, (1966), Mantle colour as a taxonomic feature in Larus argentatus and Larus fuscus, Nytt Mag Zool 13: 56-82.

Bermejo, A, (1999), Atlantic Iberian Yellow-legged Gull Larus michahellis ?, 4th International Gull Meeting, Le Portel, France (7pp).

Hampton, S, (1999), Gull Identification Website: Shades of Gray .

Howell, S N G, (2003), Shades of Gray: A Point of Reference for Gull Identification, Birding, February 32-37.

Jonsson, L, (1998), Yellow-legged Gulls and Yellow-legged Herring Gulls in the Baltic, Alula 4(3): 74-100.

Lewis, B, (2000), E. K. Barth's figure showing the mantle colors of large gulls. Available here .

Rossiter, N, (2001), Characteristics of Atlantic Yellow-legged Gulls, October 2001.

Home Page Yellow-legged Gulls