http://www.sibleyguides.com/2010/05/variation-in-immature-ring-billed-gulls-april/ Identification of North American birds and trees Sat, 04 Feb 2012 02:05:59 +0000 hourly 1 http://wordpress.org/?v=3.3.1 http://www.sibleyguides.com/2010/05/variation-in-immature-ring-billed-gulls-april/comment-page-1/#comment-63303 portrait photography gold coast Mon, 18 Apr 2011 06:41:43 +0000 http://www.sibleyguides.com/?p=2193#comment-63303 Nice pictures! thank for sharing with everyone! Nice pictures! thank for sharing with everyone!

]]> http://www.sibleyguides.com/2010/05/variation-in-immature-ring-billed-gulls-april/comment-page-1/#comment-4063 Tony Leukering Fri, 13 Aug 2010 17:11:38 +0000 http://www.sibleyguides.com/?p=2193#comment-4063 Another source of difference in fading -- in addition to original darkness of feathers -- is wintering site and how much sun the different sites see at that season. RBGUs wintering on the Great Lakes (which can be incredibly gloomy in winter) probably don't fade anywhere near as much as birds wintering in FL. While your April Boston birds almost certainly did not winter on the Great Lakes (for geographical reasons, if nothing else), various individuals could easily have come from very different wintering sites, with some, perhaps, being local winterers and others coming from farther south. Another source of difference in fading — in addition to original darkness of feathers — is wintering site and how much sun the different sites see at that season. RBGUs wintering on the Great Lakes (which can be incredibly gloomy in winter) probably don’t fade anywhere near as much as birds wintering in FL. While your April Boston birds almost certainly did not winter on the Great Lakes (for geographical reasons, if nothing else), various individuals could easily have come from very different wintering sites, with some, perhaps, being local winterers and others coming from farther south.

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