This last week has been slow for migration as a high pressure system was parked over the southeast and was creating unfavorable winds region-wide. A weak front let some birds through on Friday Oct 30, and another ridge of high pressure has re-asserted itself over Florida since then, creating fair skies and unseasonably warm and humid temperatures (grrr!). Still, we have managed to break several records this week, including the second-most birds banded in one fall (2273 as of today; record is 2561 in 2006) and the highest species diversity ever with 64 species banded in 2015 (63 in 2008). Some species all-time highs are Wood thrush at 6 (5 in 2014), Ovenbird at 368 (364 in 2006) and Painted bunting at 50 (38 in 2013). These good numbers are a result of a larger netting effort rather than an increased volume of migrants through the site; weather and structural changes in the hammock have conspired to actually reduce our birds captured per net hour over the years.
One of the more interesting species captured this week was this Nashville warbler. We have only banded two others in the last 14 years as they are very rare on the East coast. They are often mis-identified by overeager birders since they closely resemble several other species.
The left bird above is the Nashville warbler, and the right bird is the far more common Magnolia warbler. Both are close to the same size: small active warblers often seen flitting around the midstory vegetation. Both have a grey head with a distinct eye-ring and yellow underparts. Look at the wings and tail to separate these easily; the Nashville has plain olive-green wings and tail while the Magnolia has wingbars and the distinctive white spots forming a band in the middle of the tail. Maggies also have a distinct yellow patch on the rump.
A diagnostic clue is the belly of the Nashville warbler (above). This is the only species that has a white belly patch surrounded by yellow. Magnolia, Parula and Tennessee warblers all have yellow bellies and white undertail coverts, while Orange-crowned and Prairie warblers have solid yellowish underparts. Common yellowthroat females have a yellow throat and undertail coverts with a buff belly in between. This belly patch can be hard to see if you are not looking straight up at the Nashville.
More views of the Nashville with lookalike warblers: above the Nashville is on the left with a Northern parula on the right. Parulas have strong white wingbars on a bluish back, but they do look similar from some views. Notice the broken eye ring and suggestion of an eye line on the parula, as well as the necklace across the throat (less distinct in this bird, probably a young female).
Nashville and Magnolia again, with the Magnolia on the left this time. Brighter fall Magnolia warblers will also have a bit of a gray necklace on the throat and black streaks on the sides.
Some non-warblers banded recently include this hatch-year female Baltimore oriole (above) and hatch-year male Scarlet tanager (below). The tanager is just starting to acquire the jet-black wing feathers that will contrast with the brilliant red body feathers come springtime.
