Netfugl - Foto

Klaus Malling Olsen

2. dec. 2007 kl. 13:34

Denne måge er blandt de mere interessante. Meget mørktegnet dragt og en haletegning, der på flugtbilledet ser god ud for Amerikansk Sølvmåge. Jeg bedømmer dog tegning på hoved og underside til at være for uregelmæssig og grov til at passe på en TYPISK Amerikansk, der her skal være mere ensartet brun - som en underbelyst ung Gråmåge. Bestemmelse af Amerikansk Sølvmåge incl. individual variatione, er dog langt fra udredt. det kan ikke udelukkes at der er tale om en Amerikansk. Fugle som denne skaber ofte store problemer. AT en større andel af sådanne mørke varianter ses i Nordatlanten end f.eks. i Østersøen viser disse formesrs tilpasning til et barskt miljø: jo værre vejrforhold de skal klare sig igennem, jo mere mørkt er der i dragten. Mange fugle fra f.eks. Island ser ud som denne. At man så kan diskutere, om det er Amerikansk Sølvmåge - eller om der er gener fra denne i dem, er en anden sag.

Peter Hedegaard Kristensen

2. dec. 2007 kl. 13:39

Hej Under en tur til Skagen i går, fløj denne måge ind i havnen fra grenen, hvor det lykkedes os (Ole Amstrup, Søren Kristoffersen, Henrik Haaning Nielsen og undertegnede) at genfinde den. Herefter forsvandt den i vrimlen af måger på himlen. Vi var ikke sikker på noget, og f.eks heller ikke på alder, men på foto fremgår det, at det er en 2k, bla pga afrundede håndsvingfjer og generel fældning. Vi synes den ser meget spændende ud, ikke mindst pga det der lige springer i øjene, brun krop kontra lyst hoved og tændstiknæb. Går man mere i detaljer, er der også en lang række interessante ting, som det ses her er dens rygfjer uden tværvatring men med en mørk skaftestribe og udvasket brun center, dette nævnes som værende uden for europæisk sølvmåges variation. Næbfarven er grågul, hvilket også er meget godt for amerikansk. Fuglens overgump er som det ses på flugtfoto meget tværvatret og stod ikke frem i felten, mens halen synes meget mørk, kun med lyst på halesiderne. Undergumpen var ligeledes meget tværbåndet og på de yderste underhaledækfjer var det mørke klart bredere end det lyse (jeg tror ikke det er en så brugbar karakter). En anden meget interssant karakter er fuglens store dækfjer der fremstår som ensartede brune, hvorved det i flugt liger et mørkt bånd, hvilket også er en meget fin karakter på amerikank sølvmåge. Som det ses på foto er der tale em et stort og ret groft næb, hvorved fuglen fik et anderledes udtryk end vores sølvmåger. Alt ialt er der mange ting, det tyder kraftigt på amerikansk sølvmåge, og ud fra det vi har noget at undersøge, falder halen også inden for variationen, omend den meget gerne må have været helt mørk (dette beskrives dog som værende ekstrem) Men det er klart, at det (endnu engang) ikke bare lige er noget man sådan bestemmer, derfor er kommentar meget velkommen.

Peter Hedegaard Kristensen

2. dec. 2007 kl. 13:42

Og tak til Klaus for hurtig svar, jeg havde ikke set det, da jeg postede.

Hans Larsson

2. dec. 2007 kl. 13:59

Jag tycker nog att den grova teckningen på huvud och undersida är helt typiskt för en smithsonianus i andra vinterdräkt. Den jämnfärgade gråmåge-lika är väl främst en karaktär för första vinter smith? Som Klaus säger kan det vara svårt att helt utesluta varianter från Nordatlanten. Fast med en så komplett svit av postiviva karaktärer som denna fågel visar är det nog svårt att hitta en bättre kandidat för 2w smith!

Klaus Malling Olsen

2. dec. 2007 kl. 14:21

Medgiver Hans at den noget grovere tegning på undersiden kan passe på Amerikansk (flere bilder nys checkede). Et så 1-års agtigt udseende som på denne fugl passer nok bedst på Amerikansk (hvis dragtudvikling tit er noget langsommere end Sølvmågers). Det er svært at finde hjemlige Sølvmåger, der i 2. vinter ligner 1.vinter fugle så meget som her.Men igen: sporene fra de mørke nordatlantiske Sølvmåger skræmmer. Peter beskriver undergumpens bånding, hvilket ikke ses påbillederne. At der er mere mørkt end lyst her underbygger ydereligere at der kunne være tale on en Amerikansk Sølvmåge. Som Hans skriver er det nok svært at finde en bedre kandidat når vi taler om 2.winter fugle. Det var unægteligt lettere dengang man snildt vilkunne publicere en sådan fugl med tilføjelsen "med karakterer som......".

Jan Ingvaedt Jörgensen

2. dec. 2007 kl. 16:13

Fina bilder på en rightigt god 2k smithsonianus kandidat. Som Hans nämner passar undersidans teckning bra på en 2k fågel, lite längre ned på flanken bakom benen är tonen mer ensfärgad. Nedre nacke/övre mantel uppvisar lite av 1k´s ensfärgade ton. Scapular teckningen som Peter nämner, stjärt teckningen, tertial och större täckare teckninen ligger inom variationen för smithsonianus. Ljust huvud samt 'Vittruts näbb' förtar inte intrycket. JanJ

Knud N. Flensted

2. dec. 2007 kl. 20:12

Jeg mener dette er en Amerikansk Sølvmåge. Når lignende fugle træffes på Island, som Malling rigtigt skriver, så kan man jo stille spørgsmål om hvor vidt det mon ikke er Amerikansk Sølvmåge der også optræder der ind imellem? Det har jeg kraftigt på fornemmelsen, eller i hvert fald fugle der overvejende har "amerikanske" gener.

Jens Hjerrild Hansen

2. dec. 2007 kl. 21:20

Ja det ser rigtig nok spændende ud. Især med det næb. Men hvorfor er det ikke en 1K fugl når den nu har helt mørkt øje og ingen grå krops- eller dækfjer ?. Nu skal jeg ikke gøre mig til mågeekspert, men de farvemærkede 2K sølvmåger som jeg har aflæst - og mærket som pullus - har altid begyndende lyst øje og typisk en del grå rygfjer og armdækfjer. Til sammenligninger og belysning af emnet - alder - er der på nedenstående hjemmeside en række gode fotos fra TEXAS. http://www.martinreid.com/Gull%20website/gullsind.html Fuglen i Skagen mangler bare en stor fed farvering med koden "USA" God Jul Jens

Jan Ingvaedt Jörgensen

2. dec. 2007 kl. 21:25

Hi Jens. Vid 250% förstoring kan du see att öjet er lyst. JanJ

Knud N. Flensted

4. dec. 2007 kl. 20:22

Art ændret til Amerikansk (sølv)Måge (fra måge sp.) efter aftalte med Søren Kristoffersen. Indtil videre under temaet "tvivl om bestemmelsen".

Jan Ingvaedt Jörgensen

6. dec. 2007 kl. 00:04

Jeg ser att Skagen mågen er lagt ud på ID-Frontiers af Andreas Bruun kristensen. Vil bare uplyse om at linken ikke viser den aktuelle måge. JanJ

Andreas Bruun Kristensen

6. dec. 2007 kl. 08:47

Det er rigtigt, Jan. Linket virkede i starten, og jeg har da også fået et svar om Skagen-mågen. Desværre er fuglen i mellemtiden omdøbt fra måge sp. til Amerikansk Sølvmåge

Klaus Malling Olsen

6. dec. 2007 kl. 12:24

Burde disse kommentarer ikke - i lighed med kommentarer fra de folk i udlandet, der har udtalt sig - gøres tilgængelige på Netfugl, der jo var de første med fotos af fuglen. Hvad mener ABK med "desværre"?

Andreas Bruun Kristensen

6. dec. 2007 kl. 12:32

Jo, det har du ret i. Her er korrespondencen (som starter nederst): Kevin skrev: Hi Andreas. I did not really expect that the comments made on this gull could be translated to English but I thought that I would check. I am not too surprised that no comments were made on IDF. As you say, the bird is aberrant and difficult to pin down and many on IDF might not attempt to comment for these reasons. I might consider posting to IDF but I want to make sure that I understand a few things. Is this gull considered by you and your colleagues as being in second winter plumage ? I hope that when I saw the reference on the website as "2.v" or "2 vinter", that I could take this as 2nd winter. If so, this means that the plumage shown by the bird is aberrant for Herring Gull in North America and presumably in Europe as well at that age. I would like to know from you, what criteria were used to consider this as 2nd winter. Regarding the "rounded aspects to the outer primary tips" I will offer an explanation. I learned this many years ago from the late Peter Grant's "Gulls". If you do not have the book, I will quote from page 18, second edition..."the outer primaries and tail feathers of juvenile gulls, are pointed and rounded respectively. At subsequent ages (second winter onwards), the outer primaries have more rounded tips and the tail feathers are rather square-ended. Although these differences are rarely discernible in the field, they are sometimes a useful clue to age in sharp photographs". I have found the above to be quite reliable, but to determine the exact structure of the outer primaries in a photograph, as Grant says, the photo must be sharp, with the primary tips at least somewhat spread. The same is true for the rectrices. On the photos of the Skagen Havn bird, the primaries are held close together as are the tail feathers and it is difficult if not impossible to see fully the outer margins of P9 and P10, which are the most important ones. I could only sense that the outer primaries are not pointed, as in a juvenile-first winter. This is very important since the birds' plumage otherwise is quite like a 1st winter AHG and I see no other features apart from my perception of the structure of the outer primaries to conclusively age this bird as second winter. I agree with what you say about the inner primaries appearing shorter than the outer five or so. I do not understand why this is the case. By December, our Herrings in first and second winter plumages should have fully grown primaries with the outers longer than the inners. Rather puzzling. Again, I would appreciate knowing what age that you and others in Denmark assigned to this bird and the reasons for this. As I have already said, age determination is critical in considering what species this bird could be. Kevin. ----- Original Message ----- From: Andreas Bruun Kristensen To: Kevin Sent: Wednesday, December 05, 2007 5:06 PM Subject: SV: Re: [BIRDWG01] Possible American Herring Gull Hi Kevin, Thanks for the detailed response. Unfortunately, the comments cannot be translated into English. Most responses are from Danish birders, in favour of American Herring Gull. However, I think it would be more interesting with comments from observers familiar with AHG. I have only got one response (yours) about the gull. Perhaps reflecting that this is an aberrant bird - difficult to identify. If possible, I hope you will post your response on ID-frontier. Perhaps it would generate more responses. I have never heard about the age criteria "rounded aspects to the outer primary tips". Is it meant in the way that these are new feathers. On passerines I know that rounded tail feathers indicate older birds. http://www.netfugl.dk/pictures.php?id=showpicture&picture_id=19297 On this photo, the inner primaries (1-5) to my eyes seem a little longer than the outer primaries. But I guess that if the inner primaries were new feathers, they would have been paler. Best regards, Andreas Kevin skrev: Hello Andreas. I don't know if you have received comments from North America on this oddly plumaged bird but I have a few that may help. I have chosen not to post my thoughts on ID Frontiers but please feel free to messaged me back if you would like. I will first say that I wish that I could understand Danish as there have been a number of comments posted on your gull site about this bird. Can these be shown translated to English ? I live at the western end of Lake Ontario and study gulls very closely throughout the year. We see a great many Herring Gulls ( L.a.smithsonianus ), called American Herring Gull in Europe, in my area and at the Niagara River and elsewhere in Ontario. The species breeds in my city. When I first looked at the eight photos, I would have instantly stated that this bird is in first winter plumage, due to its extreme darkness overall, the well barred uppertail and undertail coverts and other features. It was only upon seeing the caption as 2. vinter. ( 2nd winter I believe ) that I looked more closely. Two features seem to support 2nd winter, while difficult to see, the rounded aspect to the outer primary tips and, less importantly, the very weakly marked greater secondary coverts. I refer to the latter as being less important from my local perspective, as our juvenile-first winter Herring Gulls can range from having heavily chequered fresh greater coverts to having very finely marked ones when fresh. I cannot clearly see that the irides are pale, nor can I see the structure of the individual tips of the rectrices as being square. These two traits would further aid in saying that this bird is 2nd winter. Realize that I am not well acquainted with your Herring Gulls, only from the literature, so I am speaking from my familiarity with our Herring Gull. I don't know how often argenteus/argentatus have tails looking like this one, but think it would be rarely. This birds' tail is very much like the tail on first and second winter Herrings seen in Ontario in being nearly all dark and is a trait which would engender thoughts of an AHG. I am taking this bird as being 2nd winter, based on the above and the best I can do is to offer features that are typical individually and in sum for our second winter Herrings as compared with the Skagen Havn bird. Firstly, the appearance of this bird would be highly unusual for our 2nd winter Herrings. I have never seen one that I have aged as second winter which is as dark as this bird. Many of our 2nd winter HGs have clear gray "saddles" ( back feathers and scapulars ). In fact, I would say that most do although some in December may have a variably small number of first winter type feathers in this area. The upperwings would have much brown feathering and would have very obvious inner primary "windows", much as I think your birds do. I usually find these windows to be more obvious in 2nd winter than in 1st winter. The head and underparts are variable in AHG but are consistenly much paler or whiter than this bird in 2nd winter plumage. The rectrices in typical 2nd winter AHG are very much like 1st winter in being very dark blackish brown with only a bit of pale mottling on the outermost feathers near the bases. The important thing is that our 2nd winter Herrings have nearly unmarked undertail and uppertail coverts and rumps. That is they lack the heavy barring shown on this bird. I do not recall ever seeing a second winter tail as shown for AHG on page 243 ( 3. ) in the Malling Olsen-Larsson book. The bird in ( 4. ) on the same page is typical here with white uppertail and rump. The heavy undertail barring on the Skagen Havn bird is also a feature more appropriate for 1st winter AHG than 2nd. I cannot say that this bird is not an American Herring Gull. The make up of the rectrices is quite suggestive. But I can say that, for the age class given, it is most atypical and is not at all consistent in plumage with what is expected, from my experience, for second winter American Herring Gull as it appears on the Great Lakes. Great caution should be used in identifying this bird. It is possible that the new second generation feathers, apart from the ones correct for the age of 2nd winter, are aberrant in that they resemble first generaton feathers. For example, the tail and uppertail-undertail areas are appropriate in appearance for first generation feathers but do not seem at all worn and abraded enough to be over one year old. I am only speculating on this point however. I hope this helps and again, I would be keen to see in English what the comments are on the gull site. If you wish, post my comments on your site. I do not subscribe to it at present. Kevin McLaughlin Hamilton, Ontario CANADA. ----- Original Message ----- From: Andreas Bruun Kristensen To: BIRDWG01@LISTSERV.ARIZONA.EDU Sent: Tuesday, December 04, 2007 11:07 AM Subject: [BIRDWG01] Possible American Herring Gull Dear birders, A possible American Herring Gull (Larus smithsonianus) was seen and photographed by 5 observers in Skagen Harbour, Northern Jutland, Denmark on December 1st 2007. Several photos can be viewed here: http://www.netfugl.dk/pictures.php?id=listpictures&species_id=968 There has been some discussion as to its identity and age. If accepted, this will be a new species to Denmark. About 5 have been claimed since 2000. I hope, that someone can comment on this gull. Regards, Andreas Bruun Kristensen Mail: AnBrKr@yahoo.dk

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