Sunday, December 6, 2009

Psuedo Nelson's Gull and others

Well we finally got some snow. This makes for much better photographic opportunities at the landfill as much of the garbage gets buried. It also makes for much better manoeuvring when the ground freezes as your not walking in deep muck. All in all its a better place when things are frozen.

Juvenile Glaucous Gull

Given the relatively warm weather most of the 4-5 thousand Herring Gulls are still around with probably 1500 plus at the Landfill yesterday morning. Noticeable changes have occurred over the last couple weeks.
First although I thought this was happening it was clear this year that the juvenile Thayer's Gull leave in late November. It has been two weeks since I have seen one and there were at least 4-6 around. Right on schedule the first adult Thayer's Gull of the season turned up last weekend. Skye Haas was telling me they find adults in the Marquette area (200 miles west on south shore of Lake Superior) consistently in late October but I virtually never see them here until late November. It was present again this weekend and given a bit of black flecking on the tail and wing coverts must be a 4th winter bird.

4th Winter Thayer's Gull

This bird certainly meets the criteria for Thayer's Gull but really has a petite structure with very rounded Kumlien's-like head.  The dark eye, strong hood, greenish yellow bill base and of course reduced white on the primaries with dark markings on P5 to P10 all fit with Thayer's.  I spied what I assumed was the same bird later but when it flew I noted it didn't have the tiny dark flecks on the tail. It returned and was cooperative for pictures. I noted that it looked very petite as well probably well within the range of Kumlien's. On examining the photos this bird only had dark markings on P6 to 10. P5 was pristine white tipped.

Adult Thayer's-Kumlien,s Gull "Intergrade"

Bruce Mactavish and Steve Howe did a study looking at dark markings on the primaries and I believe this bird would fall at the very extreme end of the Kumlien's cline and given the dark heavy hood I would call this an "intergrade" for lack of a better term. I am reluctant to use the word hybrid as that implies that Thayer's and Kumlien's are distinct species which is certainly not the case. If you believe Thayer's and Iceland Gull are distinct species and Kumlien's are a hybrid swarm then this bird is just part of that swarm. If you believe Thayer's, Kumlien's and Iceland are all part of a single variable species than this bird is just part of the cline. I prefer that former theory and see it as analogous to the Western, Olympic, Glaucous-winged Gull situation that is unfolding before our eyes.

Adult Thayer's-Kumlien's Gull "Intergrade" - "Head Close-up"

Adult Thayer's-Kumlien's Gull "Intergrade" - "Primaries Close-up"

The close-up of the head shows the "in between" eye colour and the heavy hood which would be  unusual in most Kumlien's. This is a neat bird as it is very just one small step towards Kumlien's and very closely resembles the adult Thayer's Gull present.

Well while contemplating this a large very white headed gull with a bright yellow bill and reduced black on the primaries flew by. I followed it in my binoculars thinking that this must be an adult Nelson's Gull.
It eventually returned and I could see it was a largish Herring Gull size with very little head streaking and a bright yellow bill and brighter than usual pink legs. All seemingly Glaucous Gull features.

Adult Glaucous Gull

The above picture illustartes the bright yellow-orangish bill, the lightly marked head and the deep pink-red legs typical of a winter adult Glaucous Gull.  I managed to eventually get real good looks at the "Nelson's" Gull and I noted that something was not right with its primaries.

"Pseudo Nelson's" Gull- Adult Herring Gull in Delayed Molt

Well on examining the pictures it all became clear. It appeared that P9-10 were very old and worn and P8 was only half in and the rest were fresh and full grown. Since P8 was still not grown in all the grey on the old worn P9 was visible and all this added up to a lot less black. The lack of head streaking, the bright yellow bill and the pinker than average legs could all be explained as part of a delayed molt in this adult Herring Gull (I think anyways). I am glad the bird came back because on my first look on the flyby I was quite convinced it was a Nelson's Gull.

The biggest change in the gull population since the cold weather hit is a big increase in Glaucous Gull numbers. All age classes were present with at least 15-20 juveniles. Kumlien's Gull also increased significantly with about 8-10 juveniles and 3 second cycle birds. The juvenile Lesser Black-backed made an appearance and for the first time this season I struck out on Ringed-bills.

Juvenile Kumlien's Gull

Second Winter Kumlien's Gull

The snow allowed for some semi-artistic flight shots. After about 3 hours I had majorly frozen hands and feet and my face was so cold I couldn't talk (not that I usually talk much at the landfill by myself - just to clarify as most people think your crazy hanging out at the ladfill to begin with) so I headed home. I am going to miss my usual Saturday morning session next week as I am heading for Texas to look for Hook-billed Kites at Santa Anna. The next week I will spend all of Saturday at the Landfill as part of the Sault Ste. Marie CBC.

Adult Glaucous Gull

Third Winter Glaucous Gull

Adult Thayer's -Kumlien's Gull "Intergrade"

Juvenile Great Black-backed Gull

Thanks for checking out my blog and I am keenly waiting for your insightful comments.


1 comment:

  1. Ken McIlwrick just pointed me here. Awesome shots and a great resource. We've only a handful of (Herring) gulls here in Marathon right now. The town dump has been largely converted to a transfer station and the pulp mill is shuttered. 'Lots of other good birds around. Thanks for sharing your expertise, Kirk.