A Tale of Two Grebes

A staple of my fall birding activities is scoping area reservoirs for interesting waterfowl, waterbirds, and gulls. As I was waiting out a Parasitic Jaeger between bouts of chasing gulls the other day it occurred to me how different fall Podiceps grebes showing non-breeding plumage are in comparison to their showy breeding plumages. When they are colorful, there's no mistaking Colorado's two abundant fall Podiceps, Eared and Horned Grebes. But when they are wearing their winter grays, they are amazingly similar in appearance and all to often just glanced over. Some of the best advice I've ever received about finding rare birds is to identify every bird, even the common ones. When you are competent and confident with the common ones, unusual birds (in this case, say, a basic Red-necked Grebe) will jump out at you instead of staying lost in the crowd.
Breeding Eared Grebes (above, Colorado, April) have all black necks and wispy yellow plumes that radiate out from the eye area. Note how dark feathers can be seen through the plumes, and the sharp crest atop the head. Breeding Horned Grebes (below, North Dakota, June) have a solid yellow swipe of feathers going back from the eye, a flatter head, a rufous neck, and a little white tip to the bill. No problemo, you say?

The problemo is that these birds now show a very similar pallate of white, gray, and black in about all the same places when in non-breeding (basic) plumage. Structure can still be helpful, as Eared Grebes (below, Colorado, November) typically show a more domed head than Horned. Note also the blurry-looking border between the dark cap and the light neck. Also note that darkness extends behind and below the eye (feathers known as auriculars.) Eared Grebes are often willing to forage near the edge of lakes, particularly along rocky shores. They can also be seen far from shore, though.
In contrast, winter Horned Grebes (below, Colorado, November) have a more sharply defined dark cap and the eye is right at the edge of the darkness, with white below and behind in the auriculars. Their heads almost always look flatter than Eared Grebes', and most of the time there is a white spot on the lores (feathers in front of the eyes.) If you get a good enough look, you will see that the white bill tip is retained in the winter. To me they look somewhat like dwarf Western Grebes in their basic plumage. It occurs to me like seeing Horned Grebes near shore is much rarer than with Eared Grebes.


Ready for your quiz? Which is which below?
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The left bird is a Horned Grebe while the right bird is an Eared Grebe- how'd you do??

Happy Halloween!

Owl Banding

I’ve been to several bird banding stations over the years, but over the last few weeks I’ve finally seen owl banding in action. Master bander Scott Rashid traps migrating Northern Saw-whet Owls every fall near Estes Park, Colorado, and invited me to visit. The trick used by Saw-whet banders is to play a recording of their toots in the middle of a mist net array. Even though it isn’t breeding season and you wouldn’t expect migrants to be territorial, the little ‘Swets fly in to check out the noise and bop into the nets. Interestingly, the owls usually are caught very near the ground, so apparently they are flying in just above the tops of the grasses as they investigate the sound. Once, Scott caught a Long-eared Owl- perhaps it was hoping to poach a wee Saw-whet? He also once caught a Northern Pygmy-Owl, and indeed we heard an annoyed Pygmy vocalizing nearby at dusk although it didn’t come in to the nets.

Saw-whets are really small- it is hard to imagine by seeing pictures of the owls alone, but in hand you really get a perspective of their diminutive nature. They are cavity nesters and so have to fit in woodpecker holes, after all. Little is known about their migration and wintering habits since they are generally silent and very secretive when they aren’t on breeding territories. The only wintering Saw-whets I’ve seen have been in dense junipers during the day, seemingly oblivious to the world around them.

Another bander I know once climbed a ladder and hand-captured a migrating Saw-whet Owl by just picking it up off of its branch. After measuring and banding it he returned it to the same branch where it spent the rest of the day before resuming its migration that night.

Scott does frequent net checks to avoid having the owls stay netted for too long and to discourage foxes or other predators who would grab an entangled owl. If foxes are seen around, Scott shuts down banding for the night. Once extracted they are banded and quickly measured prior to release. Scott aims to have them inside for only about 5 minutes so they won’t get too hot or stressed (banding is done at a generous homeowner’s property and Scott sets up his tools on a ping-pong table in the basement.) Note the orange juice can on the scale- birds are weighed in tubes to keep them secure and still and it turns out that OJ cans are perfectly sized for ‘Swets (another funny example is the use of Pringles cans for small accipiters- scroll down in this blog post to see the technique in action.)

Even a really plump female just approaches 100 grams- about 3.5 ounces for you fans of the imperial system of measurement. Most are only about as heavy as an American Robin. My favorite thing about the banding is that Saw-whets will often perch on a branch for quite a while after they are released- of the 4 birds we caught two flew away immediately but the other two loitered for quite a while (one for over an hour), allowing for some neat photography. All of my other Saw-whet pics are of uncaptured birds that I had to work pretty hard for but you’ve got to take the easy photo opps like these when they present themselves!

Digiscoping Workshop this Weekend!

I'm excited to be instructing a digiscoping class this coming Saturday (10 October) and hope to see many of you faithful readers there! The class is being offered through the South Suburban Parks and Recreation district in Littleton at the Carson Nature Center and South Platte Park- class info and registration links can be found here. Thanks much to Tom Bush at Front Range Birding for arranging the class and for lining up the sponsors (S &S Optika, Front Range Birding Company, and Mike's Camera) and talent. I'm really looking forward to working with my co-instructors and buddies Jeff Bouton of Leica Sport Optics and Clay Taylor of Swarovski Optik. The forecast is currently calling for a high in the low 40's with a chance of snow- if you are coming, bundle up (we'll be in the field about half the time.)

I've updated my Digiscoping Tips and Tricks File in preparation for the class, but you can also click the link to get a PDF copy of it.

While we're at it, I also have the 2009 Nikon digiscoping system brochure available as a PDF.

I just got a loan of some great gear from Nikon- their FSB-U1 universal digiscoping adapter and a Coolpix P6000 camera along with the 20/25X Long Eye Relief eyepiece to put on my 65mm EDG Fieldscope. I'll blog about the rig soon and welcome any questions folks have about it. I'll also have the rig set up at the workshop for folks to check out in person.

Another really exciting piece of gear that I can't wait to try out in the field is Nikon's FSA-L2 Digital SLR Adapter. It lets you connect a Nikon DSLR to an EDG scope, turning it into a super-telephoto zoom (750 - 2,625mm or 600 - 2,100mm on the 85mm and 65mm models, respectively, for most DSLRs. Full-frame DSLRs (like the D3X) yeild 500mm - 1,750mm or 400mm - 1,400mm on the 85mm and 65mm models, respectively.) I don't think it is quite on the US market yet but when it drops it is going to make some big ripples!! I have it ready to go and will be happy to show anyone how it works at the workshop and in a future blog post.

Kingbird Confirmation

I had the pleasure of birding at of my favorite places on Colorado's Eastern Plains yesterday, The Nature Conservancy's Fox Ranch. While this working ranch is closed to the public, Ted Floyd arranged for a small group of us to conduct a bird survey on the property yesterday. Click here for Ted's summary of our trip (including 6+ Le Conte's Sparrows, a staggering number for Colorado).

One of the many interesting birds we found was this kingbird. We are presuming it to be a Western Kingbird but given the late date (the bulk of Westerns clear out of CO by mid-September or so according to Colorado Birds by Robert Andrews and Robert Righter) and the similarity of a few other more southerly kingbird species, I thought I'd post a couple of pics of the bird so folks can have a gander and chime in on the ID if they feel so inclined.

Unfortunately, this is the only angle of the bird that I have- no shots of the back or from the side which would be very informative.

Nikon Digiscoping!

The theme of the month at Nikon's Birding Optics page is digiscoping- check out the digiscoped bird pics slide show that plays when you open the page! There's also a link to a nice little digiscoping video on the bottom of the page. And some guy you may have heard of is the featured ProStaffer of the month, too!

Washed-out Wilson's Warbler

I took a nice little birding trip to the Chico Basin Ranch after work on Friday, spending the night and then birding a cool Saturday at this well-known Colorado hot spot. Besides birding, I enjoyed catching up with friend and fellow Nikon Birding ProStaff member Brian Gibbons, who is running the banding station there for the Rocky Mountain Bird Observatory this fall.

It was a busy day at the nets, with nearly 100 birds banded. Wilson's Warblers led the tall, and among them was a very unusual one that was mostly lacking melanin pigmentation. In birding circles, individuals like this are usually known as leucistic, although the condition may also be called dilute plumage. On a normal Wilson's Warbler melanin pigments darken the cap, wingtips, tail, bill, and legs. Yellow coloration is from caroteniod pigmentation, derived from plants instead of synthesized by the bird. The olive-greenish back of a normal Wilson's Warbler is from a mix of melanin and caroteniod pigments.
So when most of the melanin isn't present, you get a bright yellow bird like this one, with very pale wingtips and tail, a yellow back and cap, a pink bill, and pink legs. When compared to normal Wilson's Warblers (hatch-year female, left, & male, right), you can see the effects of having normal melanin vs. greatly reduced melanin. Below are a few more comparisons vs. a normal hatch-year female.