the Medium terns in Late Summer

I walked Tiscornia to Jean Klock yesterday without shorebirds of interest, but there were some quite tame terns in with the gulls.  In the spring the terns are fairly flighty, these ones have clearly become accustomed to people.  Which was good since I was having trouble telling them apart from a distance.

The problem is that you don't really think of them as having different plumage in the fall as the spring, but they change enough to be troublesome.  The Common is on the left above and the Forster's on the right.  When I'm up close, the shorter legs and trimmer build of Common stands out.  At the right angle the darker mantle of Common is helpful, but at a lot of sun angles there's not a ton of difference even with direct comparison.  With direct comparison the redder bill and legs of Common is frequently a shade darker in the field than the orange of Forster's

Here's a Forster's showing another problem with fall ID:

 It's either moulting or has broken off its outer tail feathers meaning that the tail falls short of the end of the wings as Common generally does.  In spring Forster's tail will extend an inch past the primaries.

This bird, a little farther along in moulting (as evidenced by the cap) has the tail at the proper length.

The primaries are also noticeably darker in the fall.  Tern primaries have a fine bloom on the feathers which gives fresh feathers a much whiter look.  With that worn off Forster's primaries become medium cold gray at some angles rather than the brighter white of spring.

It varies though, upon both individuals and the angle.

Moving to Common, they also have darker wings than they exhibit in spring, quite blackish when folded.

 The above group are 3 Commons in front (with the front most bird still having grayish underparts and a full cap with the Common on the right being 1 year old) and a longer-legged rangier Forster's in the back.

The primaries aren't as dark in the spread wing than as when folded, which doesn't make it easier to tell them apart.

 

Finally the one-year old Common's that are present.

 

The dark carpal bar (which juvies will also show when they arrive) is a dead giveaway that it's a Common.

 

The (quite faded) one-year-olds are quite pale in flight.

 

The other ID difference you may have noticed is that a portion of the Common Terns are banded, I didn't see any banded Forster's.

 

Speaking of which, I added a comment from one of the plover researchers, one of the Piping Plover juvies is from Ludington and one from Sleeping Bear.



 



One of these does not belong

I've tracked down some vireo articles but still need to go through and crop in all the pics to go over it carefully so I'm just going to go for the fallback plan, Tiscornia pics.

May is when Laughing Gulls start showing up.  I don't think I've ever seen one in a big group of Caspian Terns though.  Caspian numbers have been way down this year.  I don't know if that's because of the long period of N winds in the last third of April or if it relates to decreased salmon fingerling stocking this year.

If the bird had flown 2 inches higher I'd have had a great shot of it with the red lighthouse in the background, instead it was buried in the shadow as it went by and I went with this shot a few frames later. Note how there's no white between the gray of the upperwing and the black of the primaries like a Franklin's would have:

There's been a ton more Common Terns on the other hand than usually there are in the spring.  We had 60-70 of them on the beach the other day.  Here's one with a Forster's.

The Common obviously is on the left with darker gray underparts (at least in this pretty close to full breeding bird), a slightly shorter redder bill,  noticeably shorter legs, and a tail that falls short of the primary tips instead of extending past.  The Forster's also shows lighter primaries, though sometimes this can be affected by the angle of the lighting.

The two can be harder in flight though. Common (above) has darker wings and Forster's much whiter primaries, but Forster's still does have some dark in the trailing edge of the underwing and again lighting can affect the whiteness of the upperwing primaries. I sometimes think that Forster's has longer wings, but this may be optical illusion caused by the whiter primaries showing up better:

Finally a sub-adult Lesser Black-backed Gull who's just the bill short of being full adult; this bird still has some winter head streaking left on the nape.

warm Arctic air

South winds bring Arctic Terns, who knew? I spent the morning at Tiscornia; I'd been home about 20 minutes when Tim called that he had an Arctic Tern. It was nice to have the bird at Tiscornia, it never really felt right to only have the bird at Three Oaks.

Unlike the Sabine's I whiffed on chasing earlier in the fall, Tim had the bird at water's edge when I arrived.

The white secondaries showed nicely in the sun.

At rest, the key points to separate it from Commons are the shorter bill, shorter legs, and more extensive dark cap. That being said, it would take a good look to call an Arctic at rest by itself.

You can somewhat compare the leg length at least with the Common in the background.

This is a photo that probably hasn't been taken many times in Michigan, Arctic on the left, Common in the middle, and Forster's on the right.

The trailing edge of the underwing has only a minimal gray trailing edge. About twice as much of the feather is a darker gray in Common Tern.

Another view of those white secondaries and the generous hood...

Twice it gagged up some mucus, I'm not sure if this is a common behaviour in medium terns or not.Check out how the wind is blowing it back, not even touching the ground.

Assuming the MBRC searchable database is up-to-date, this is the 20th state record and the 6th county record. The most recent Michigan record was the Three Oaks bird.

oops

So, in the Hudsonian Godwit post, I mentioned a flock of about a dozen willets that flew by as I was with the family. I saw with the naked eye a flock of shorebirds with wing patterns and bright white rumps. Something about them made me run for the camera. They were flying away by the time I got on them with the viewfinder.

With 500 good pics of the Hudwit it took a few days to really examine this first series of pics. As I got them cropped though, the trail bird here stood out to me. It really doesn't have a strong wing pattern and has the tail of a Hudsonian.

I sent the pic to Tim to see if the time stamp matched a time stamp of the featured bird on the beach to see if this was a second Hudsonian. We-ell, he quickly pointed out that "dude, they're all hudwits."

What are you going to do. Here's another comparison of the original Hudwit with the willets. Yes, the godwit does have a bit of a wing pattern, but it also has the white rump stand out a lot stronger with the black, rather than gray, tail.

Furthermore, while in some lighting and angles the flying away Hudwits have fairly strong wingstripes, the white doesn't extend onto the secondaries.

Here's what a Common Tern thinks of my ID skills...

right and wrong terns

I don't think I have any group of pics that I've labeled and re-labeled than medium sized terns. I went back to the beach with the family again yesterday. There were 2 avocets and a turnstone in addition to the more usual stuff, but terns are starting to accumulate.

This Common Tern allowed a close approach and is still in pretty full breeding plumage though the bare parts colors are starting to fade.

This next one is well into the moult, with a white forehead and some darker gray in the carpal bar area. It obviously has lost a lot of color from the bill.

Finally a juvenile Forster's Tern; they're easy with the big black cheek patch. He's kind of overexposed, the Commons are easier to photograph with their grayer breasts.

There is still some dark in the wings of the juvie Forster's at least.

Finally, a Black-bellied Plover that did a fly-by as well.

boucoup (?) common terns

I checked Tiscornia this evening after work so I wouldn't completely miss a N winds day (and the first clear day after the dregs of a hurricane no less). By the time I arrived at about 4pm there was no waterfowl movement, but there were as many birds on the beach as I'd ever seen including 400+ common terns spread along the beach in 3 large groups. I counted 421 but there's surely at least some error in that number. There were at least another 100 over the brown river water flowing out into the lake. I looked as best I could for a little gull (or any tern that stood out) without finding anything of great interest though I could easily have spent another 2 hours or so to watch the birds turn over more. The juvie common terns had lost most of their brown edging and were distinguishable mainly based on the black carpal bar, though their 2 month old or so primaries were clearly a shade paler than the adults'. Most of the adult birds were developing white foreheads though probably 10% of the birds still sported bright bills and black foreheads. I didn't see any Forster's or Caspians. This pic is fairly representative:

Bonaparte's gulls were also on the beach in greater numbers than they have been. The adults have mostly completed the moult to winter plumage though this bird is missing/re-growing primaries 8 and 9. When that last primary falls out it will have a quite short-winged look and could give an initial impression of a little gull.
This bird however had completed the primary moult as had most of the other adults:

There were good numbers of savannah sparrows in the dune grass. They were obviously freshly moulted as well, given how dark, crisp, and contrasting their plumage was. I wondered in the field if they were maybe a different subspecies than the somewhat paler more washed out birds I'm accustomed to seeing in spring and summer, but per Sibley range maps there's not a different subspecies to the north. I know warblers only moult their body plumage once a year (in fall), with the spring plumage becoming slowly revealed with feather wear, that's probably the case in these guys then as well.