Hi John, This following excerpt written by Lars Jonsson - Alula 3/1998, is taken from Gullresearch.org a site that Phil Jeffery offered up earlier in his response. I have bolded the area that might interest you.
*Herring Gulls L. argentatus (major/omissus) with yellow legs* There are Herring Gulls in the Baltic region with specific features worth keeping in mind when discussing the identification of *cachinnans* and *michahellis*. The yellow-legged element, usually referred to as Yellow-legged Herring Gulls, or *omissus*, is a widely discussed subject among gull taxonomists, on which I can not resist giving some personal views. In the following discussion I basically refer to the statistic material presented by Barth 1968 & 1975, Kilpi & Hario 1968, Mierauskas 1991, Greimas & Buzun 1991, Hario 1997 and my own material from specimen collections, as well as field studies from Gotland and other areas of Europe. *From Barth's work we can conclude that yellow-legged individuals are present throughout the whole of Scandinavia. They are however much more common at certain localities than others and there is a south-west (grey-pink) and north-east or east-north-east (yellow) cline. We still do not have a solution as to why some argentatus have yellow legs and others not, but it may simply be diet-related.* The yellow element among Herring Gulls seems to be more common in areas with a predominating fresh or brackish water habitat. In the Baltic Sea, with its brackish water, anything from 10-75 % of the population in the breeding colonies were recorded as having more or less yellowish legs. It may be that yellow legs did predominate in the past at inland localities in the Balticum, parts of Finland and north-west Russia (Kumari 1978). At Lake Saimaa in Finland 100% showed yellowish legs in samples dating back to the l950’s (Barth 1968) and at the Teichu raised peat bogs in Latvia yellow-legged birds still constituted two-thirds of the population in samples from 1987-90 (Mierauskas *et al.* 1991). The yellow (as well as orange and red) colour is caused by carotenoids and Lonnberg (1933) found such substances in Herring Gulls with pink legs as well. However it seems reasonable to assume that there is an element of genetic inheritance for developing yellow legs which are stronger in these areas. The percentage of birds with yellow legs within a colony also varies between different years (Hario 1997). It is quite possible that the leg colour can shift back and forth on one individual, as this happens in Common Gull *Larus canus* (Rattiste *pers. comm*.). It is also well known that the colour of the legs, bill, and orbital ring changes with age and season. Mierauskas *et al.* (1991) have shown that: 1) The Herring Gulls breeding on peat bogs in Latvia (Teichu) show some differences from the coastal breeding birds (St Petersburg) in having a longer bill, longer wing, longer tarsus and middle toe. 2) Studies of vocalisation and behaviour (and wingtip pattern) have not, so far, upheld the theory that the Baltic yellow-legged gulls are related, closely or distantly, to *cachinnans* from the Aralo-Caspian area. On the contrary, the results support a treatment of cachinnans and argentatus as separate species. On Tue, Mar 24, 2015 at 11:20 PM, <redk...@optonline.net> wrote: > Does anyone have an idea as to the cause for the different coloration in > the legs. Could it be diet related? > > John Turner > > ----- Original Message ----- > From: Shaibal Mitra > Date: Tuesday, March 24, 2015 10:08 pm > Subject: RE: [nysbirds-l] Fwd: [ebirdsnyc] Possible Yellow legged Gull at > Plumb Beach 20150324 > To: NYSBIRDS-L > > > Both of our common large gull species, Herring and Great Black- > > backed, occasionally deviate from their usual dull pink legs to > > more or less yellow legs. Some examples of this phenomenon can > > be seen starting here: > > > > > https://picasaweb.google.com/109808209543611018404/LaridaeIIHerringGreatBlackBackedGulls#5376517305977522738 > > > > From: "js...@nyu.edu [ebirdsnyc]" > > > nore...@yahoogroups.com>>Date: March 24, 2015 at 4:02:50 PM EDT > > To: > > > Subject: [ebirdsnyc] Possible Yellow legged Gull at Plumb Beach > > 20150324Reply-To: js...@nyu.edu > > > > > > > > Today at 10:30 AM an isolated possible Yellow legged Gull at > > Plumb Beach. Near a group of 12 Oystercatchers and 40 Brant, > > > > I am not an expert, any feedback is welcome. I have additional > > images if needed. > > > > Thank you. > > > > Juan Salas > > > > > > > > Yellow legged Gull Plumb Beach > > 20150324 > > > > > > [image] > > > > > > Yellow legged Gull Plumb Beach 20150324 > > Explore > > js472's photos on Flickr. js472 has uploaded 78 photos to Flickr. > > > > > > View on www.flickr.com > > > > Preview by Yahoo > > > > > > > > Yellow legged Gull Plumb Beach b > > 20150324 > > > > > > [image] > > > > > > Yellow legged Gull Plumb Beach b 20150324 > > Explore js472's photos on Flickr. js472 has uploaded 78 photos to > Flickr. > > > > > > View on www.flickr.com > > > > Preview by Yahoo > > > > > > > > > > > > __._,_.___ > > ________________________________ > > Posted by: js...@nyu.edu > > ________________________________ > > Reply via web > > post • Reply to sender • Reply to group • Start a New Topic • > Messages in this topic (1) > > ebirdsnyc: bird sightings from the NYC area > > Visit Your > > Group > > > > * New > > Members 2 > > > > [Yahoo! > > Groups] > > • > > Privacy • Unsubscribe • Terms of Use > > > > . > > > > > > __,_._,___ > > -- > > NYSbirds-L List Info: > > Welcome and Basics > > Rules and Information > > Subscribe, Configuration and > > LeaveArchives: > > The Mail Archive> l...@cornell.edu/maillist.html>Surfbirds > > BirdingOnThe.Net > > Please submit your observations to > > eBird!-- > > > > ________________________________ > > Connect with CSI on Social Media> > > > > -- > > > > NYSbirds-L List Info: > > http://www.NortheastBirding.com/NYSbirdsWELCOME > > http://www.NortheastBirding.com/NYSbirdsRULES > > http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm > > > > ARCHIVES: > > 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html > > 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L > > 3) http://birdingonthe.net/mailinglists/NYSB.html > > > > Please submit your observations to eBird: > > http://ebird.org/content/ebird/ > > > > -- > -- > *NYSbirds-L List Info:* > Welcome and Basics <http://www.northeastbirding.com/NYSbirdsWELCOME> > Rules and Information <http://www.northeastbirding.com/NYSbirdsRULES> > Subscribe, Configuration and Leave > <http://www.northeastbirding.com/NYSbirdsSubscribeConfigurationLeave.htm> > *Archives:* > The Mail Archive > <http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/NYSBirds-L> > BirdingOnThe.Net <http://birdingonthe.net/mailinglists/NYSB.html> > *Please submit your observations to **eBird* > <http://ebird.org/content/ebird/>*!* > -- > -- 風 Swift as the wind 林 Quiet as the forest 火 Conquer like the fire 山 Steady as the mountain Sun Tzu <http://refspace.com/quotes/Sun_Tzu> *The Art of War* <http://refspace.com/quotes/The_Art_of_War> (\__/) (= '.'=) (") _ (") Andrew Baksh www.birdingdude.blogspot.com -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
