Rarity Season Begins!

Derek Lovitch, author of How to Be a Better Birder and an avid birdwatcher, is at it again with his blog, Maine Birding Field Notes, posting about another exciting day of bird-watching as ‘Rarity Season’ starts up. Keep your eyes peeled for some more rare sightings coming your way!


AUDUBON’S WARBLER at Fort Foster!

Yesterday, I had the pleasure of leading our annual “York County Rarity Roundup” Field Trip for York County Audubon today. With no rarities to “round up,” we set out to find our own, birding from Kittery through Wells.  We followed a very similar route to what Jeannette and I always do on our monthly south-coastal run.  The difference today was that with a group, and with so many birds at FortFoster, we never made it out of Kittery by lunchtime.  Too bad that meant we just HAD to have lunch at Loco Coco’s Taco (mmm, chili relleno burrito…)!

It was a very birdy day overall, even in the windy afternoon.  A preliminary total of 63 species of birds included 9 species of sparrows, 5 species of shorebirds, and 4 species of warblers.  Excellent-for-the-season bird diversity was augmented by 5 species of butterflies, 3 species of mammals, 2+ species of dragonfly, 1 reptile (Garter Snake), and 1 amphibian (Spring Peeper).

The bird of the day by far was “Audubon’s” Yellow-rumped Warbler that I found at FortFoster.  This western subspecies of Yellow-rump (it once was, and I believe will likely once again be considered a full species) has only occurred – or should I say, been detected – in Maine a few times.  I can only think of one recent record, an adult that nearly-overwintered at Dyer Point in Cape Elizabeth a few years ago.

If anyone wants to look for it, the bird was flycatching and occasionally eating Red Cedar berries along the west edge of the park. Follow the entrance road into the park, until the large gravel parking lot opens up on the left. The bird was loyal to the right (west) edge here, especially around the big cedars in the mowed lawn.

Noah Gibb and I photographed the bird extensively, and I was also able to borrow a phone to get a voice recording.  All aspects of the bird – from plumage to voice – fit perfectly with a pure “Audubon’s” Warbler.

I first glimpsed the bird sallying for insects in and out of shadows.  The overall extremely cool gray plumage tone – top to bottom – brought to mind a first fall female Pine Warbler. But something wasn’t right.  The bird began to call, and that was definitely not the call of a Pine Warbler…but what was it?  We saw the bird briefly a few times, the pieces began to come together, and then as it flew to another tree the bright yellow rump became evident.  “Audubon’s Warbler!!!!” I exclaimed.
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We studied the bird extensively for at least a half hour, occasionally in perfect light for prolonged periods.  I scribbled notes, and encouraged others to do the same before we discussed the bird any further.  Plenty of “Myrtle” Warblers (the Eastern subspecies of Yellow-rumped) were nearby for convenient comparison.

- Obvious “Yellow-rumped” Warbler with bright yellow rump, overall size and shape, bill size and shape, etc.
- Exceptionally cool gray overall plumage tone, not suggesting the brownish tones of even the palest Myrtles.
- Very diffuse streaking below.
- Very restricted and pale yellow “blobs” on sides of chest.
- Very subtle and restricted yellow on throat, not visible in all light conditions, but quite obvious in good sunlight.
- Lacked the extension of pale on the throat that “points” up around the back of the auriculars as on Myrtle.  Therefore, throat patch appeared rounded, or encircled by the cool gray of head.
- Auriculars only marginally darker than rest of head, often looking concolorous.
- Call note very different from surrounding Myrtles, much sharper and not as “blunt.”
- Exceptionally dull plumage highly suggestive of a first fall female, but the lack of a definite molt limit within the greater coverts prevents us from clinching the age. (reference: The Warbler Guide, Stephenson and Whittle, 2013)

Good bird!  And yes, Rarity Season is most definitely in full swing!  Good thing it appears that, after a prolonged drought, I have finally refound my rarity-finding mojo.  Phew.

Now, about that Saltmarsh Sparrow – which I admittedly called an “Interior” Nelson’s Sparrow in the field…  Expecting to see an “Interior” Nelson’s Sparrow based on the timing, micro-habitat, and behavior, I reached for my camera before I fully studied the bird. After firing off some photos, and making sure everyone got on the bird, it took off and we never saw it again. Although I mentioned that the malar looked “quite dark,” I didn’t second-guess the call until I looked at photos on the computer this afternoon.  Yeah, it’s a Saltie.  The malar is not only dark and distinct, but it frames a clear white throat.  The breast streaking is dark and extensive, the bill has a fleshy-pink cast, and it is simply too long-billed for an “Interior” (subspecies alterus or nelsoni; I don’t believe they are identifiable in the field).  As a final clincher, note the fine streaks towards the rear half of the supercilium.  Behavior and timing wise: odd for a Saltmarsh.  Plumage: essentially textbook for a Saltmarsh.  Therefore, “After further review, the call (in) the field is overturned.”
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This post is part of a series, explore additional posts here<< Migration Quiz Monday: The Swamp QuestionThe Warbler Guide to Aging and Sexing Sheet >>