Moerdijk Field Research 2005-2006
(last update: 14 August 2010)
Roland-Jan Buijs
Theo Muusse
Mars Muusse
Introduction
Methods
Age, origin & sex
Retrapped Birds
Upperparts Greytone
Black on Primary Coverts
Black on Primaries
P10 and P9 Patterns
P5 Pattern
Red & Black on Bill
Iris & Orbital Ring
Primary Moult
Discussion
References
Upper-part Grey Tone
Herring Gull upper-parts were clearly paler than upper-parts of Lesser Black-backed Gulls, without any overlap in grey tone (figure 1). The modal grey tone for the Herring Gulls sampled was 5 (range 3-7) and for Lesser Black backed Gull 11 (range 8-15).
Figure 1: Upper-part Grey Tone in Herring Gull (n = 292) and Lesser Black-backed Gull (n = 888) from the Moerdijk colony 2005 & 2006. Based on Agfa Grey Scale 0-20.
Breeding gulls, Moerdijk, the Netherlands: grey tone 11 in LBBG oJH (left), grey tone 8.5 in 14cy hybrid m35 (centre, ringed pullus green EV65 at Dintelhaven-Maasvlakte in 1992) & grey tone 6.0 in HG m36 (right).
Breeding Lesser Black-backed Gulls, Moerdijk, the Netherlands: grey tone 11 in o31 (average) and 15 in oLP (dark).
Read further on RESULTS: 2. BLACK ON GREATER PRIMARY COVERTS >
Herring Gull L.a. argenteus adult JH, 06 May 2006. Grey tone: Kodak 3.
Herring Gull L.a. argenteus adult JP, 06 May 2006. Grey tone: Kodak 3.
Herring Gull L.a. argenteus adult 43, 16 May 2005. Grey tone: Kodak 7.
Lesser Black-backed Gull L.f. graellsii adult SP, 05 May 2006. Grey tone: Kodak 8.
Lesser Black-backed Gull L.f. graellsii adult AP, 02 May 2006. Grey tone: Kodak 8.
Lesser Black-backed Gull L.f. graellsii adult LP, 16 May 2005 & 08 May 2006. Grey tone: Kodak 15.Lesser Black-backed Gull L.f. graellsii adult AW, 02 May 2006. Grey tone: Kodak 15.
Lesser Black-backed Gull L.f. graellsii adult E9, 04 May 2006. Grey tone: Kodak 15.