Saturday, April 30, 2011

Swainson's and Krider's Hawks

After about 5 years of hawk-watching attempts in the dunes, we hit ideal winds with remarkable results. After a couple days of north winds shutting down migration during which the big low pressure tornado system in the southeast caused a lot of westerly winds. Last night it turned around out of the southeast pushing birds northward at last. SE winds push the raptors up against the lakeshore concentrating them.

We'd only been up in the dunes an hour when this bird appeared:
It's a first spring Swainson's Hawk.

The bird stuck out even with binoculars. We both were watching it in the scopes when Tim made sure I was on the bird. The long narrow wings with a darker trailing edge to the underwing made it a pretty good Swainson's candidate. If a person depended on plumage though, it likely could have been passed off as a young redtail as the upperparts were a plainish brown and it still has a mostly juvenile head and neck pattern lacking the contrasting face and breast band. An adult would also have even darker flight feathers (see the difference several photos farther down this post between adult and first spring Broadwing).

While Swainson's was very much on our radar, I never expected to see the next bird in Berrien. The first instant it appeared in the bins the all white head made me think Mississippi Kite. The next instant the buteo shape came out; Ferruginous was the next thought in my mind, but it clearly lacked the rufous thigh V. Tim put the name to what it had to be, a Krider's Hawk:

You'll have to take my word that the the un-photographed back was a grayish brown, the tail grayish with a whiter base. The entire head was white however. The upperparts of the flight feathers showed paler contrasting sections in some of the un-moulted sections. ID points are the white head, white tail, lack of a belly band, and in the underwing very pale pantagial bars (the dark feathers on the inner part of the leading edge of the wing) and pale commas. If I read the book correctly, Wheeler (2003) considers Krider's to be the light morph of the Eastern redtail. Sibley says that it's always outnumbered by "normal" light morph birds without attempting to define it with a trinomial. Ligouri and Sullivan (2010) propose that it once was a distinctive subspecies of Redtail that is getting swamped by coming back into contact by the other subspecies. As I read Wheeler, I see that his winter range map puts the bird into southern Illinois and eastern Kentucky, so perhaps this bird should not be as uncommon in Michigan as I would have expected. That being said, I see that the Krider's is a MBRC review bird, but I find no records in the searchable data-base. Maybe they're just not being submitted, or perhaps since they're just a subspecies/form they haven't been put into the database.

Next is a more typical red-tail, again a first-spring bird:

Broad-wings are the species most associated with high spring migration in many birders' minds. I only clicked off 26 though; I would have predicted a much higher count on the day with a Swainson's. They were all ones and twos however, 25mpg SE winds (with faster gusts) probably prevented thermals and kettles from forming.

The differences between the adult and first spring Broad-winged is similar to Swainson's, note that the young bird in the next pic has retained juvenile facial pattern and much more muted patterning to the wings and tail...

Sharp-shins were the dominant species. Tim clicked off over 150, though some certainly slipped past us. It looks like I managed to delete the best sharpie pic in the editing process...

And for those of you who would like to return to the more typical May fare, here's a Swamp Sparrow in decent light.

Works Cited:
Ligouri J and BL Sullivan. A study of Krider's Redtailed Hawk. Birding 42(2): 38-45. 2010.

Wheeler BK. Raptors of Eastern North America. Princeton University Press. 2003.

Friday, April 29, 2011


Tim picked out this Bittern at Lincoln Twp Beach Park this morning, easily the best bird I've had in the county this year. It's only the 2nd I've seen in the county (the previous one Andre's from April 30th a few years ago), and probably only about the 6th I've seen/heard in my life at all.
It was nice to have a bird that would sit still and let me play around with exposure settings.

The sun was a little high to be really ideal though.
This Tree Swallow at Three Oaks was showing off its iridescence, though it was pretty hard to really capture. I should have tried a little harder to get some more light on the face.

If I can get a few more shots of Common Terns I may have a medium-sized tern post in me, but Caspians at least are an easy ID...

Finally, after a Black-throated Green "sparrow" yesterday foraging on the ground, here's a White-throated "warbler" in the Forest Lawn canopy.

With Wilson's Phalaropes, a decent year bird yesterday, and American Bittern, a good year bird today, we'll see if we can keep the momentum going tomorrow with some actual migration winds forecasted.

Thursday, April 28, 2011

Black-throated Green Sparrow?

The weather is finally turning, yesterday's birding was essentially rained out so I did some of the office work I had hanging over my head. Today was overcast with a few sprinkles here and there and I could finally spend a full day outside.

This BT Green warbler was a first on a couple fronts. I think it's probably the first time I've seen one forage on the ground (though with the trees barely even budding perhaps the may-apples are the closest thing it could find to canopy). I know it's the first time I've ever had my first of the year BT Green as a seen-only bird; usually the zee-zee-zee-zoo-zee floats down from the treetops first.
White-throated sparrows, on the other hand, are abundantly seen in the undergrowth.

I've always had trouble with processing my ruby-crowned photos, they always seem oversharpened. Maybe I just need a better image to start with.

Off course it's spring, so more flower pics, I think my best ever of Wild Ginger:

Marsh Marigolds are peaking at Floral too.

I tried getting some reflection shots, this one would have been better had it not included the two blossoms in the entire swamp that are past their prime:

Monday, April 25, 2011

Easter finches

I had my first of the year Purple Finch on the feeder on Saturday while we were getting ready for Easter festivities. I took a little time-out to stand on the back porch and fire a few frames. Most years I see Purple Finch on the feeder in late March. Either they were late this year, missed my feeder with the first wave of birds, or I just haven't had time to notice them.
For some reason the white in front of the eye always stands out more to me in photos than it does in real life.

Goldfinches continued the Easter egg-colored bird theme.

My schedule will finally relent some later this week, hopefully enough to allow somewhat more regular posts...

Saturday, April 16, 2011

it must be spring ...

I write as it was practically snowing on the way home from work this evening. I did finally get over for the wagtail a day ago, a really lousy digi-scoped video grab is at the end, until then it's the expected migrants and flora of mid-April... I caught this kinglet as it reached for a tiny insect presumably, though for all I know it's searching for tree plankton. This Fox Sparrow is from Tiscornia
There was a Hermit Thrush on the sidewalk as I walked into the house tonight. This one's from Floral though.
The requisite shots of some of my favorite spring wildflowers, bloodroot,
Trout lily,
and Dutchman's Breetches

Finally the Wagtail. Tim got a flight shot that I think is pretty supportive of it being an alba White Wagtail, rather than the lugens Black-backed subspecies, based on the flight drawings in Sibley, but I could be wrong. My pic, on the other hand, is only about half a step past the I-guess-that's-not-a-Gray-Jay level of identification.

Tuesday, April 12, 2011

Yellow Wagwings

I haven't had time in my schedule to chase the White Wagtail, but we did see a heck of a lot of flickers a few mornings ago. A good overnight SE wind with a lot of movement on the radar led to a lot of bird's reverse migrating along the lakeshore the following morning, headlined by close to 400 flickers. With that many birds surely one will be close enough for a pic right??? It was harder than I thought since woodpeckers' undulating flight leads to a lot of time with their wings folded as evidenced in this montage:
Flickers are easy to ID on the wing, other birds are harder, with different field marks in flight than perched. Shape and proportion plays a big role, but calls can help, like with these pipits,
or the bzzz of this Blue-gray Gnatcatcher,
or the seeee of these waxwings.
Other times you just have to look for the odd bird out of the flock, which frequently is a cowbird (see the leftmost bird in this group)
Sometimes, though the bird will take pity on us and land in the tree under which we're standing...

Saturday, April 2, 2011

How bluebirds invented email...

... during the Civil War no less. OK, so this one is going to be a bit of a stretch. I haven't had occasion to do a SORA search lately, but in my first walk into the river bottom this spring, I ran into a couple bluebirds. They were fairly cooperative, working the same opening that held a couple phoebes and assorted robins, creepers, and kinglets. I was a little surprised to see that they were both males foraging calmly without any territorial disputes. I tried to look up in the literature when bluebirds pair-bond. There were a couple of gems that came up in the search, one from the Wilson Journal (Alsop 1971) describing how a family of bluebirds got entirely too mingled with a feeding flock. One of the juvies tried begging from a Great-crested Flycatcher which promptly copulated with it. There was another one (Gower, 1936) that describes how an author in the 1860's had termed the structural blue layer of feathers "email" of all things.
There's actually a fair amount of bluebird research that's been published from Michigan. Benedict Pinkowski wrote a number of articles and short notes from a study area in Macomb in the 1970's. He found that the initial nesting period where eggs were laid was from April 6 to May 15. I guess these two aren't horribly behind, especially given that it's been cold enough that not a lot of stuff is singing. A Depression-era article from Illinois (Musselman, 1939), described how generally the bluebirds would time their breeding such that their eggs would be hatched prior to the return of House Wrens since the wrens apparently will pierce the eggs to try to free up a cavity for their own use. Years with cold snaps forcing the bluebirds to re-lay would lead to much less breeding success since more nests would then be able to be destroyed by wrens. Both eBird and Jon's recent 10 year review show essentially identical bargraphs for House Wren, numbers increase rapidly in the last half of April until they're pretty much back in force by the beginning of May. I hadn't realized that House Wrens had such a negative effect on Bluebirds, but a Wisconsin study of 2600 nests (Radunzel et al, 1997), found that House Wrens accounted for about 40% of the total nest failures in bluebirds, the same precent of the total failures attributable to cats and House Sparrows combined! Interestingly their study also found that bluebirds preferred to nest in standard bluebird boxes, but had higher fledging rates in open topped boxes since wrens avoided these.

The cardinals on the other hand are fully territorial. This one briefly popped up to some soft pishing.
as did this Fox Sparrow, though I only managed to improve my view from completely obstructed to mostly obstructed.

Works cited:

Alsop, FJ. Great Crested Flycatcher Observed Copulating with an Immature Eastern Bluebird. Wilson Bulletin: 83 (3) Jul-Sep, 1971.

Gower, C. The cause of blue color as found in the bluebird (Sialia sialis) and the Blue Jay (Cyanocitta cristata). Auk: 53(2) Apr-Jun 1936.

Pinkowski, BC. Annual productivity and its measurement in a multi-brooded passerine, the Eastern Bluebird. Auk 96(3) Jul-Sep, 1979.

Musselman, TE. The effect of cold snaps up ont the nesting of the Eastern Bluebird (Sialia sialis sialis). JFO 10(1) Jan, 1939.

Wuepper, JT. The Birds of Berrien County Michigan 10 year Summary 2000-2009. Berrien Birding Club. 2011.

Radunzel LA, DM Muschitz, VM Bauldry, and P Arcese. A long-term study of the breeding success of Eastern Bluebirds by year and cavity type. JFO 68 (1) winter 1997.