These are some examples of young Glaucous-winged Gulls illustrating some issues on difficulty of ageing birds as well as variation. All birds were photographed by myself in Half Moon Bay, California. Alvaro Jaramillo.
GO TO: SECOND CYCLE; THIRD CYCLE.
Known Age Western Gulls for comparison.
Dec. 11, 2006 - Quite a classic look for early winter, this bird just starting some molt out of juvenile in the mantle.
Dec 11, 06 - A darker, more uniform juvenile. Same date as above bird. Note that hybrids with Western tend to have molted more juvenile upperparts out by this time of year.
Dec 25, 2006 - A pale and advanced bird. Now is this a second cycle? Maybe, but primaries look nicely pointed, suggesting a first cycle bird. The well marked coverts also suggest first cycle. The greater coverts look second cycle though. It is a toss up, seeing the bird fly would help (white rump or barred rump). Fully dark bill is also a better trait for the first cycle. It does get tricky to age these Glaucous-wings, much more so than Western Gulls.
Dec 30, 2006 - A nice speckly bird, molting mantle out of juvenile.
Feb. 10, 2006- The primaries and often outer secondaries and outer greater coverts can have a gray color in first cycle Glaucous-winged which suggests an older age than first cycle. However, these are the juvenile flight feathers of this bird, it is just the way that some Glaucous-wings are. The well barred rump is a good first cycle feature in flight.
Feb. 15, 2006 - Similar bird to the one above, a few days later.
Feb. 15, 2006 - Another bird in flight with well barred rump. The white-headed look is a bit strange, but not unheard of.
June 27, 2006 - A bird molting into the second cycle, worn out first cycle feathers remain. But then again, it may be molting into the third cycle?
Dec. 13, 2005 - This one is troublesome, it likelyis in its third cycle, but then again most third cycle birds I see are more adult like than this one. So is it an "advanced" second cycle, maybe? You decide! Part of the issue that confounds the ageing of Glaucous-wings is the tendency for some to become gray on the primaries and secondaries early in life, even in first cycle (see above). If this bird had a browner tone to the primaries and secondaries, we would likely call it a second cycle bird. The more you think about it, the more confusing it becomes.
Dec 31, 06 - A rather white-headed bird, with contrastingly darker primaries. Third or second cycle? The very adult like secondaries suggest it is actually a third...but maybe not.
January 7, 2006 - This one is like the bird above, but it is not showing the secondaries (which may or may not be grayish on this bird) so it looks more passable for a second cycle (the wing look pretty brownish).
Jan 7, 2006 - A good brown winged second cycle, with restricted gray on mantle. Phew, an easy one to age.
Feb. 10, 2006- Another straight forward second cycle. Note that this one overlaps with some first cycle birds, but lacks the well barred rump of that age, and has pale bill base.
Feb. 15, 2006 - A real brown bodied bird, luckily we can't see the upperparts so less information to argue about.
Feb. 17, 2006 - Brown coverts with contrasting gray mantle is the classic second cycle look.
Dec. 11, 2006 - The primaries and secondaries are nearly adult like on this bird, with a tad more extensive dark on the outer primaries than an adult. There is extensive gray on the coverts and the rump is clean white. This is clearly a third cycle bird. .
Feb. 10, 2006 - Very adult like, with restricted white on tail. One could suggest that this is in fact in the fourth cycle. However, color banded (known age) Western Gulls here which we know are in their third cycle often show this look. They are adult like, show more extensive dark on primaries, some brown wash on wings somewhere, and some dark on tail. So unless Western Gulls mature much faster than Glaucous-winged Gulls, it is perfectly reasonable to say this is just a third cycle bird. NOTE - the very dark primary tips suggest that this bird has some Western genes.
Feb. 13, 2006 - Similar to the above bird but more dark on tail, noticeable brown on median and marginal coverts.
Feb. 13, 2006 - Very adult like with dark on tail.
